* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 1 BYTE-SIZE 10 CREATION-DATE 23073453367 AUTHOR "rms")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

(locality a-mem)

a-10-pc (0)
a-10-flags (0)

;Address of Q containing the left half of memory location 0.
;The memory lives in an array.
;Each pdp-10 word occupies two consecutive Qs,
;the left half in the first and the right in the second.
a-10-mem-0-addr (0)

(modulo 20)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Load the simulated memory location whose number is in M-A
;into the internal accumulator.
load-10-mem
	(jump-less-than m-a (a-constant 20) load-10-ac)	;Check for ACs referenced as memory.
	((vma-start-read) add m-a a-10-mem-0-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) m+a+1 m-a a-10-mem-0-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Store the internal accumulator into the simulated memory location
;whose address is in M-A.
store-10-mem
	(jump-less-than m-a (a-constant 20) store-10-ac) ;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-a a-10-mem-0-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) m+a+1 m-a a-10-mem-0-addr)
	(check-page-write)
	(popj)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 2 BYTE-SIZE 10 CREATION-DATE 23073453374 AUTHOR "rms")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.
;The pdp-10 PC lives in M-B.

(locality a-mem)

a-10-flags (0)

;Address of Q containing the left half of memory location 0.
;The memory lives in an array.
;Each pdp-10 word occupies two consecutive Qs,
;the left half in the first and the right in the second.
a-10-mem-0-addr (0)

(modulo 20)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) m+a+1 m-e a-10-mem-0-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) m+a+1 m-e a-10-mem-0-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) m+a+1 m-e a-10-mem-0-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) m+a+1 m-e a-10-mem-0-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b (a-constant 20) xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read) add m-b a-10-mem-0-addr)
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) m+a+1 m-b a-10-mem-0-addr)
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-addr-comp)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	((oa-reg-high) dpb m-b oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-b oah-a-src a-zero)
	(jump-xct-next xct-10-insn)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-addr-comp
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-what)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-op)
	((m-c) m-1)
	((m-d) m-

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 3 BYTE-SIZE 10 CREATION-DATE 23073453374 AUTHOR "rms")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

(locality a-mem)

a-10-flags (0)

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

(modulo 20)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-addr-comp)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-addr-comp
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-what)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Jump instructions

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 4 BYTE-SIZE 10 CREATION-DATE 23073453375 AUTHOR "rms")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

(locality a-mem)

a-10-flags (0)

;Address of Q containing the left half of simulated memory m." u(.o 0.Í{Ui$ m$gu i mw$2 .g  mm QEQmq0 ,$,.s8 6.se2 m(w$ (o ".o2$"4u(w$ 2.Í mq0m,$,m0mm$gum ees (0iÍÍ{ees$22 .g  ".ou (o(o& ui$ s(&iu i mg .g 2(,4m u$e ,$,.s8 m." u(.o 0.Í{Ui$ s(&iu i mw$2 .g  mm QEQmq0 ,$,.s8 6.se2 m(w$ (o ".o2$"4u(w$ 2,Í{(,,$e( u$m8 g.mm.6(o& ui$ m$gu i mw$2.Í{Ui42, ui(2  ees$22 (2  m6 82 q000000 ,.s$ ui o ui u (o  mq0m,$,m0mm$gum ees.Í mq0m,$,m0ms(&ium ees (0iÍÍ{ees$22 .g m$gu i mg .g ,$,.s8 m." u(.o 20,Í{42$e g.s u$2u(o& ui$ Q u. 2$$ 6i$ui$s q.(ou2  u  o .Í mq0m,$,m20mm$gum ees (0iÍÍ(,.e4m. 20iÍÍ{Ui$2$  s$ ui$ m$gu i mw$2 .g ui$ qeqmq0g2 2(,4m u$e  ""4,4m u.s2.Í mq0m "m0mm$gu (0iÍÍ(,.e4m. 20iÍÍ{Ui$2$  s$ ui$ s(&iu i mw$2.Í mq0m "m0ms(&iu (0iÍÍ(,.e4m. 20iÍÍ(m." m(u8 (m,$,iÍÍ{$u ui$ 2(,4m u$e q" gs.,   qeqmq0 g.s, u q" (o m2.Í2$umq0mq"ÍÉ(q.qkm gu$smo$yuÍÉ (,mci  ee ,m2 ( m".o2u ou mqiiÍ       ((,mci  ee ,mc  mq0m,$,m0mm$gum eesiÍÍ{$u ui$ q" (o qeqmq0 g.s, (o m2.Í&$umq0mq"ÍÉ(q.qkm gu$smo$yuÍÉ (,m2i 24c ,mc  mq0m,$,m0mm$gu eesiÍÉ((,m2i ,kq ,m2iÍÍ{M. e  oe 2u.s$ 2(,4m u$e  ""4,4m u.s2 ( o4,c$s (o miÍ{gs., ui$ (ou$so m  ""4,4m u.s  oe ui$ U s$&(2u$s.ÍÍ{u.s$ ui$ (ou$so m  ""4,4m u.s (ou. ui$ 2(,4m u$e  ""4,4m u.sÍ{6i.2$ o4,c$s (2 (o m.Í2u.s$mq0m "ÍÉ((. ms$&mm.6i eqc ,m  . mm me$2u  m{$s.iÍÉ(( mq0m "m0mm$gui ,mqiÍÉ(q.qgm gu$smo$yuÍÉ (. ms$&mm.6i eqc ,m  . mm me$2u  m{$s.iÍ       (( mq0m "m0ms(&iui ,m2iÍÍ{M. e ui$ 2(,4m u$e  ""4,4m u.s 6i.2$ o4,c$s (2 (o mÍ{(ou. ui$ (ou$so m  ""4,4m u.s.Ím. emq0m "ÍÉ((. ms$&mi(&ii eqc ,m  . im m2s"  m{$s.iÍÉ((,mqi  mq0m "m0mm$guiÍÉ(q.qkm gu$smo$yuÍÉ (. ms$&mi(&ii eqc ,m  . im m2s"  m{$s.iÍ       ((,m2i  mq0m "m0ms(&iuiÍÍ{u.s$ ui$ U s$&(2u$s (ou. ui$ 2(,4m u$e  ""4,4m u.sÍ{6i.2$ o4,c$s (2 (o m.Í2u.s$mq0m "muÍÉ((. ms$&mm.6i eqc ,m  . mm me$2u  m{$s.iÍÉ(( mq0m "m0mm$gui ,muiÍÉ(q.qgm gu$smo$yuÍÉ (. ms$&mm.6i eqc ,m  . mm me$2u  m{$s.iÍ       (( mq0m "m0ms(&iui ,msiÍÍ{M. e ui$ 2(,4m u$e  ""4,4m u.s 6i.2$ o4,c$s (2 (o mÍ{(ou. ui$ U s$&(2u$s.Ím. emq0m "muÍÉ((. ms$&mi(&ii eqc ,m  . im m2s"  m{$s.iÍÉ((,mui  mq0m "m0mm$guiÍÉ(q.qkm gu$smo$yuÍÉ (. ms$&mi(&ii eqc ,m  . im m2s"  m{$s.iÍ       ((,msi  mq0m "m0ms(&iuiÍÍ{M. e  oe 2u.s$ , (o ,$,.s8 ( ees$22 (o miÍ{gs., ui$ (ou$so m  ""4,4m u.s  oe ui$ U s$&(2u$s.ÍÍ{M. e ui$ 2(,4m u$e ,$,.s8 m." u(.o 6i.2$ o4,c$s (2 (o mÍ{(ou. ui$ (ou$so m  ""4,4m u.s.Ím. emq0m,$,ÍÉ(k4,qmm$22mui o ,m$ ( m".o2u ou 20iÍÉÉÉm. emq0m "m,m$iÉ{i$"* g.s 2 s$g$s$o"$e  2 ,$,.s8.ÍÉ((w, m2u sums$ ei  ee ,m$  mq0m,$,m0mm$gum eesiÍÉ("i$"*mq &$ms$ eiÍÉ((,mqi s$ em,$,.s8me u iÍÉ((w, m2u sums$ ei  ee ,m$  mq0m,$,m0ms(&ium eesiÍÉ("i$"*mq &$ms$ eiÍÉ(q.qk (,m2i s$ em,$,.s8me u iÍÍm. emq0m "m,m$ÍÉ((. ms$&mi(&ii eqc ,m$ . im m2s"  m{$s.iÍÉ((,mqi  mq0m "m0mm$guiÍÉ(q.qkm gu$smo$yuÍÉ (. ms$&mi(&ii eqc ,m$ . im m2s"  m{$s.iÍ       ((,m2i  mq0m "m0ms(&iuiÍÍ{u.s$ ui$ (ou$so m  ""4,4m u.s (ou. ui$ 2(,4m u$e ,$,.s8 m." u(.oÍ{6i.2$  ees$22 (2 (o m.Í2u.s$mq0m,$,ÍÉ(k4,qmm$22mui o ,m$ ( m".o2u ou 20iÍÉÉÉ2u.s$mq0m "m,m$iÉ{i$"* g.s 2 s$g$s$o"$e  2 ,$,.s8.ÍÉ((6s(u$m,$,.s8me u i ,mqiÍÉ((w, m2u sum6s(u$i  ee ,m$  mq0m,$,m0mm$gum eesiÍÉ("i$"*mq &$m6s(u$iÍÉ((6s(u$m,$,.s8me u i ,m2iÍÉ((w, m2u sum6s(u$i  ee ,m$  mq0m,$,m0ms(&ium eesiÍÉ("i$"*mq &$m6s(u$iÍÉ(q.qkiÍÍ2u.s$mq0m "m,m$ÍÉ((. ms$&mm.6i eqc ,-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions


xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)

;;;???These are in the wrong order
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-soj)
	(i-10-aos)
	(i-10-sos)
	(i-10-cai)
	(i-10-cam)
(locality i-mem)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-overflow-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.

;;;??? These are in the wrong order.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-equal)
	(cond-10-less)
	(cond-10-grtr)
	(cond-10-le)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-always)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 5 BYTE-SIZE 10 CREATION-DATE 23073453401 AUTHOR "rms")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

(locality a-mem)

a-10-flags (0)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions


xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)

;;;???These are in the wrong order
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-soj)
	(i-10-aos)
	(i-10-sos)
	(i-10-cai)
	(i-10-cam)
(locality i-mem)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-overflow-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.

;;;??? These are in the wrong order.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-equal)
	(cond-10-less)
	(cond-10-grtr)
	(cond-10-le)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-always)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-dest-halfword-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-src-halfword-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-dest-halfword-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-src-halfword-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-src-halfword-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
;;;??? correct sense?
	(jump-if-bit-clear pdp10-halfword-store-left-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
;;;??? These are in the wrong order.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-mem-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 6 BYTE-SIZE 10 CREATION-DATE 23075640617 AUTHOR "RMS")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

(locality a-mem)

a-10-flags (0)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions


xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)
;PDP10-JUMP-SUBCLASS should be bits 70 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.
;PDP10-JUMP-CONDITION should be bits 7 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;PDP10-HALFWORD-FETCH-RIGHT-BIT should be the 4 bit of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
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;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
inc-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;TRNN, etc.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-10-test-source
	(p-bit xct-10-test-immed)
	(p-bit load-10-mem-t)
(end-dispatch)
(locality i-mem)

xct-10-test-immed
	(popj-after-next
	 (m-r) m-e)
	((m-t) a-zero)

(locality d-mem)
(start-dispatch 2 0)
d-10-test-condition
	(xct-10-test-2)	;Do not skip.
	(xct-10-test-skip-if-0)
	(xct-10-test-skip-always)
	(xct-10-test-skip-not-0)
(end-dispatch)
(locality i-mem)

xct-10-test-skip-not-0
	(jump-xct-next xct-10-test-skip-always)
	(popj-equal m-i a-zero)
;;;??? Will that work?

xct-10-test-skip-if-0
	(popj-not-equal m-i a-zero)
xct-10-test-skip-always
	(popj (m-b) add m-b (a-constant 1))

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 7 BYTE-SIZE 10 CREATION-DATE 23075640617 AUTHOR "RMS")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

(locality a-mem)

a-10-flags (0)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions


xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)
;PDP10-JUMP-SUBCLASS should be bits 70 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.
;PDP10-JUMP-CONDITION should be bits 7 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;PDP10-HALFWORD-FETCH-RIGHT-BIT should be the 4 bit of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

;PDP10-OPERATION-DIRECTION should be the low 2 bits of the opcode.
;PDP10-OTHER-HALFWORD-ACTION should be the 30 bits of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.
xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-ac-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
inc-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;TRNN, etc.

;PDP10-TEST-MODIFICATION should be the 60 bits of the opcode.
;PDP10-TEST-SOURCE-BIT should be bit 10 of the opcode.
;PDP10-TEST-SWAPPED-BIT should be bit 1 of the opcode.
;PDP10-TEST-CONDITION should be bits 6 of the opcode.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)
;Maybe store new contents in AC.
	(dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-10-test-source
	(p-bit xct-10-test-immed)
	(p-bit load-10-mem-t)
(end-dispatch)
(locality i-mem)

xct-10-test-immed
	(popj-after-next
	 (m-r) m-e)
	((m-t) a-zero)

;Decide whether to skip, and maybe do so.
;Called with (dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
;The thing to test is whether M-I is nonzero.

(locality d-mem)
(start-dispatch 2 0)
d-10-test-condition
	(xct-10-test-2)	;Do not skip.
	(p-bit xct-10-test-skip-if-0)
	(p-bit xct-10-test-skip-always)
	(p-bit xct-10-test-skip-not-0)
(end-dispatch)
(locality i-mem)

xct-10-test-skip-not-0
	(jump-xct-next xct-10-test-skip-always)
	(popj-equal m-i a-zero)
;;;??? Will that work?

xct-10-test-skip-if-0
	(popj-not-equal m-i a-zero)
xct-10-test-skip-always
	(popj (m-b) add m-b (a-constant 1))

;Compute and store the new contents of the accumulator.
;Called by (dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-10-test-modification
	(next-10-insn)
	(xct-10-test-set-zero)
	(xct-10-test-complement)
	(xct-10-test-set-one)
(end-dispatch)
(locality i-mem)

xct-10-test-set-zero
	((m-1) andca m-1 a-t)
	((m-2) andca m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-complement
	((m-1) xor m-1 a-t)
	((m-2) xor m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-set-one
	((m-1) ior m-1 a-t)
	((m-2) ior m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 10 BYTE-SIZE 10 CREATION-DATE 23075640622 AUTHOR "RMS")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

;The simulated PDP10 flags, except for CARRY 0, CARRY 1 and OVERFLOW,
;are kept in A-10-FLAGS.  The flags can be used to help decode
;the reason why the microcode simulator exited.
;For example, the pdl overflow flag may be set.

(locality a-mem)

a-10-flags (0)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Entry and exit.

;Call with (%pdp10-simulator <pc> <flags> <address of memory array>)
;It returns two values on the stack: the new pc and the new flags.
enter-10-simulator
	(misc-inst-entry %pdp10-simulator)
	((a-10-mem-0-left-addr) c-pdl-buffer-pointer-pop)
	((a-10-flags) c-pdl-buffer-pointer-pop)
	((m-e) c-pdl-buffer-pointer-pop)
	(jump jump-10-jump)	;Jump to the PC now in M-E.

exit-10-simulator
	(call get-10-pc-and-flags-t)	;Get flags in M-T, pc in M-R.
	((c-pdl-buffer-pointer-push) m-r)
	(popj)				;return flags to misc insn destination (push).

pdl-10-overflow
	((m-1) (a-constant pdp10-pdl-overflow-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump exit-10-simulator)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc and flags in internal accumulator (m-1 and m-2)
get-10-pc-and-flags
;;;???

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Get the pc and flags in other accumulator (m-t and m-r)
get-10-pc-and-flags
;;;???
	(popj-after-next
	 (m-r) sub m-b a-10-mem-0-leftaddr)
	((m-r) m+1 m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions


xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)
;PDP10-JUMP-SUBCLASS should be bits 70 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.
;PDP10-JUMP-CONDITION should be bits 7 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;PDP10-HALFWORD-FETCH-RIGHT-BIT should be the 4 bit of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

;PDP10-OPERATION-DIRECTION should be the low 2 bits of the opcode.
;PDP10-OTHER-HALFWORD-ACTION should be the 30 bits of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.
xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-ac-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
inc-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;TRNN, etc.

;PDP10-TEST-MODIFICATION should be the 60 bits of the opcode.
;PDP10-TEST-SOURCE-BIT should be bit 10 of the opcode.
;PDP10-TEST-SWAPPED-BIT should be bit 1 of the opcode.
;PDP10-TEST-CONDITION should be bits 6 of the opcode.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)
;Maybe store new contents in AC.
	(dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-10-test-source
	(p-bit xct-10-test-immed)
	(p-bit load-10-mem-t)
(end-dispatch)
(locality i-mem)

xct-10-test-immed
	(popj-after-next
	 (m-r) m-e)
	((m-t) a-zero)

;Decide whether to skip, and maybe do so.
;Called with (dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
;The thing to test is whether M-I is nonzero.

(locality d-mem)
(start-dispatch 2 0)
d-10-test-condition
	(xct-10-test-2)	;Do not skip.
	(p-bit xct-10-test-skip-if-0)
	(p-bit xct-10-test-skip-always)
	(p-bit xct-10-test-skip-not-0)
(end-dispatch)
(locality i-mem)

xct-10-test-skip-not-0
	(jump-xct-next xct-10-test-skip-always)
	(popj-equal m-i a-zero)
;;;??? Will that work?

xct-10-test-skip-if-0
	(popj-not-equal m-i a-zero)
xct-10-test-skip-always
	(popj (m-b) add m-b (a-constant 1))

;Compute and store the new contents of the accumulator.
;Called by (dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-10-test-modification
	(next-10-insn)
	(xct-10-test-set-zero)
	(xct-10-test-complement)
	(xct-10-test-set-one)
(end-dispatch)
(locality i-mem)

xct-10-test-set-zero
	((m-1) andca m-1 a-t)
	((m-2) andca m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-complement
	((m-1) xor m-1 a-t)
	((m-2) xor m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-set-one
	((m-1) ior m-1 a-t)
	((m-2) ior m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

;Stack instructions

i-10-push
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

i-10-pop
	(call-xct-next load-10-ac)
       ((c-pdl-buffer-pointer-push) m-e)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) c-pdl-buffer-pointer-pop)
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)


i-10-popj
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
;Set the PC.
	((m-b) add m-r a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Decrement the halves of the AC.
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)

i-10-pushj
	(call load-10-ac)
	(call-xct-next get-10-pc-and-flags-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

;Byte instructions.

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 11 BYTE-SIZE 10 CREATION-DATE 23075640622 AUTHOR "RMS")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

;The simulated PDP10 flags, except for CARRY 0, CARRY 1 and OVERFLOW,
;are kept in A-10-FLAGS.  The flags can be used to help decode
;the reason why the microcode simulator exited.
;For example, the pdl overflow flag may be set.

(locality a-mem)

a-10-flags (0)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Entry and exit.

;Call with (%pdp10-simulator <pc> <flags> <address of memory array>)
;It returns two values on the stack: the new pc and the new flags.
enter-10-simulator
	(misc-inst-entry %pdp10-simulator)
	((a-10-mem-0-left-addr) c-pdl-buffer-pointer-pop)
	((a-10-flags) c-pdl-buffer-pointer-pop)
	((m-e) c-pdl-buffer-pointer-pop)
	(jump jump-10-jump)	;Jump to the PC now in M-E.

exit-10-simulator
	(call get-10-pc-and-flags-t)	;Get flags in M-T, pc in M-R.
	((c-pdl-buffer-pointer-push) m-r)
	(popj)				;return flags to misc insn destination (push).

pdl-10-overflow
	((m-1) (a-constant pdp10-pdl-overflow-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump exit-10-simulator)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc and flags in internal accumulator (m-1 and m-2)
get-10-pc-and-flags
;;;???

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Get the pc and flags in other accumulator (m-t and m-r)
get-10-pc-and-flags
;;;???
	(popj-after-next
	 (m-r) sub m-b a-10-mem-0-leftaddr)
	((m-r) m+1 m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions


xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)
;PDP10-JUMP-SUBCLASS should be bits 70 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.
;PDP10-JUMP-CONDITION should be bits 7 of the opcode.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;PDP10-HALFWORD-FETCH-RIGHT-BIT should be the 4 bit of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

;PDP10-OPERATION-DIRECTION should be the low 2 bits of the opcode.
;PDP10-OTHER-HALFWORD-ACTION should be the 30 bits of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.
xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-ac-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
inc-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;TRNN, etc.

;PDP10-TEST-MODIFICATION should be the 60 bits of the opcode.
;PDP10-TEST-SOURCE-BIT should be bit 10 of the opcode.
;PDP10-TEST-SWAPPED-BIT should be bit 1 of the opcode.
;PDP10-TEST-CONDITION should be bits 6 of the opcode.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)
;Maybe store new contents in AC.
	(dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-10-test-source
	(p-bit xct-10-test-immed)
	(p-bit load-10-mem-t)
(end-dispatch)
(locality i-mem)

xct-10-test-immed
	(popj-after-next
	 (m-r) m-e)
	((m-t) a-zero)

;Decide whether to skip, and maybe do so.
;Called with (dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
;The thing to test is whether M-I is nonzero.

(locality d-mem)
(start-dispatch 2 0)
d-10-test-condition
	(xct-10-test-2)	;Do not skip.
	(p-bit xct-10-test-skip-if-0)
	(p-bit xct-10-test-skip-always)
	(p-bit xct-10-test-skip-not-0)
(end-dispatch)
(locality i-mem)

xct-10-test-skip-not-0
	(jump-xct-next xct-10-test-skip-always)
	(popj-equal m-i a-zero)
;;;??? Will that work?

xct-10-test-skip-if-0
	(popj-not-equal m-i a-zero)
xct-10-test-skip-always
	(popj (m-b) add m-b (a-constant 1))

;Compute and store the new contents of the accumulator.
;Called by (dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-10-test-modification
	(next-10-insn)
	(xct-10-test-set-zero)
	(xct-10-test-complement)
	(xct-10-test-set-one)
(end-dispatch)
(locality i-mem)

xct-10-test-set-zero
	((m-1) andca m-1 a-t)
	((m-2) andca m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-complement
	((m-1) xor m-1 a-t)
	((m-2) xor m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-set-one
	((m-1) ior m-1 a-t)
	((m-2) ior m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

;Stack instructions

i-10-push
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

i-10-pop
	(call-xct-next load-10-ac)
       ((c-pdl-buffer-pointer-push) m-e)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) c-pdl-buffer-pointer-pop)
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)


i-10-popj
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
;Set the PC.
	((m-b) add m-r a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Decrement the halves of the AC.
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)

i-10-pushj
	(call load-10-ac)
	(call-xct-next get-10-pc-and-flags-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

;Byte instructions.

;PDP10-BP-POSITION and PDP10-BP-SIZE are needed.

i-10-ldb
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
;compute bp effective address.
	(call load-10-mem)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 12 BYTE-SIZE 10 CREATION-DATE 23075640631 AUTHOR "RMS")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

;The simulated PDP10 flags, except for CARRY 0, CARRY 1 and OVERFLOW,
;are kept in A-10-FLAGS.  The flags can be used to help decode
;the reason why the microcode simulator exited.
;For example, the pdl overflow flag may be set.

(locality a-mem)

a-10-flags (0)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Entry and exit.

;Call with (%pdp10-simulator <pc> <flags> <address of memory array>)
;It returns two values on the stack: the new pc and the new flags.
enter-10-simulator
	(misc-inst-entry %pdp10-simulator)
	((a-10-mem-0-left-addr) c-pdl-buffer-pointer-pop)
	((a-10-flags) c-pdl-buffer-pointer-pop)
	((m-e) c-pdl-buffer-pointer-pop)
	(jump jump-10-jump)	;Jump to the PC now in M-E.

exit-10-simulator
	(call get-10-pc-and-flags-t)	;Get flags in M-T, pc in M-R.
	((c-pdl-buffer-pointer-push) m-r)
	(popj)				;return flags to misc insn destination (push).

pdl-10-overflow
	((m-1) (a-constant pdp10-pdl-overflow-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump exit-10-simulator)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc and flags in internal accumulator (m-1 and m-2)
get-10-pc-and-flags
;;;???

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Get the pc and flags in other accumulator (m-t and m-r)
get-10-pc-and-flags
;;;???
	(popj-after-next
	 (m-r) sub m-b a-10-mem-0-leftaddr)
	((m-r) m+1 m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions


xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)
;PDP10-JUMP-SUBCLASS should be bitp 40 lg thg lp`ldg/��(ll`clkt{ d/ogo+�(ptcst/dkppct`h 0 kohkckt/x`t/ogxt/ckt+�d/30/kwop/pwc`lcpp�‹(k/30/`ck+�‹(k/30/`co+�‹(k/30/kwop+�‹(k/30/phkp+�‹(k/30/clk+�‹(k/30/clp+�‹(k/30/plk+�‹(k/30/plp+�(ll`clkt{ k/ogo+��k/30/`co�‹(`cll llcd/30/ogo/t+�‹(`cll llcd/30/c`+�‹(`cll pwc/30/ol/glcdp+�‹(dkppct`h (k/csd `lod/30/phkp+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��k/30/`ck�‹(`cll llcd/30/c`+�‹((o/3+ pwc o/3 c/g+�‹(kwop/kg/ckt/`lgcs pdp30/`css{/0/ckt o/3 k/30/`ck/3+�‹((o/3+ pwc o/3 (c/`loptcot 3++�k/30/`ck/3�‹((o/3+ tswo`ctg/tl/hclgtlsd o/3+�‹((o/3+ tswo`ctg/tl/hclgtlsd o/3+�‹(dkppct`h (k/csd `lod/30/phkp+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��k/30/kwop�‹(`cll llcd/30/c`+�‹(dkppct`h (k/csd `lod/30/kwop+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��k/30/phkp�‹(`cll llcd/30/ogo+�‹(`cll/olt/gswcl o/c c/{gsl ptlsg/30/c`+�‹(dkppct`h (k/csd `lod/30/phkp+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��k/30/clk�‹(`cll llcd/30/c`+�‹(`cll ko`/30+�‹(`cll ptlsg/30/c`+�‹(dkppct`h (k/csd `lod/30/kwop+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��k/30/clp�‹(`cll llcd/30/ogo+�‹(`cll ko`/30+�‹(`cll ptlsg/30/ogo+�‹(`cll/olt/gswcl o/c c/{gsl ptlsg/30/c`+�‹(dkppct`h (k/csd `lod/30/phkp+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��k/30/plk�‹(`cll llcd/30/c`+�‹(`cll dg`/30+�‹(`cll ptlsg/30/c`+�‹(dkppct`h (k/csd `lod/30/kwop+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��k/30/plp�‹(`cll llcd/30/ogo+�‹(`cll dg`/30+�‹(`cll ptlsg/30/ogo+�‹(`cll/olt/gswcl o/c c/{gsl ptlsg/30/c`+�‹(dkppct`h (k/csd `lod/30/phkp+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+��8Kwop ls Phkp lo Pkdo lg Kotgsocl C``wowlctls/��8Dl kt tkth co koptsw`tklo�8‹(dkppct`h (k/csd `lod/30/phkp+ pdp30/kwop/`lodktklo o/0 d/30/kwop/`lodktklo+�8Thg K/CSD phlwld cg @LOD/30/KWOP tl kwop, @LOD/30/PHKP tl phkp/�8PDP30/KWOP/@LODKTKLO phlwld cg cktp 4 lg thg lp`ldg/��(ll`clkt{ d/ogo+�(ptcst/dkppct`h 0 kohkckt/x`t/ogxt/ckt+�d/30/kwop/`lodktklo�‹(ogxt/30/kopo+‹8Kwop ogwgs�‹(`lod/30/lgpp+�‹(`lod/30/gswcl+�‹(`lod/30/lg+�‹(`lod/30/cltc{p+�‹(`lod/30/dg+�‹(`lod/30/og+�‹(`lod/30/dsts+�(god/dkppct`h+�(ll`clkt{ k/ogo+��`lod/30/lg�‹(kwop/kg/ckt/pgt pdp30/pkdo/ckt o/3 `lod/30/cltc{p+�`lod/30/gswcl�‹(kwop/olt/gswcl o/3 ogxt/30/kopo+�‹(kwop/olt/gswcl o/3 ogxt/30/kopo+�‹(kwop cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;PDP10-HALFWORD-FETCH-RIGHT-BIT should be the 4 bit of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

;PDP10-OPERATION-DIRECTION should be the low 2 bits of the opcode.
;PDP10-OTHER-HALFWORD-ACTION should be the 30 bits of the opcode.
;PDP10-HALFWORD-STORE-RIGHT-BIT should be the 40 bit of the opcode.
xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p$b`t ftimr$90$iimffrd$kmmir „€)p$b`t ftimr$90$iimffrd${mt „€)p$b`t ftimr$90$iimffrd$mytmod „)mod$d`{pitki „)mfkim`tp `$dmd „„ftimr$90$iimffrd$mytmod„€)k}dp$`f$b`t${mt pdp90${`oo$b`t d$2 ftimr$90$iimffrd${mt „ftimr$90$iimffrd$kmmir„€)pfpk )d$9  i${mrf „„ftimr$90$iimffrd${mt„€)pfpk )d$9  )i$kfo{tiot ??????  „„ykt$90$iimffrd$prm{mrvm$ftimr$iimf„€)d`{pitki pdp90$fpmrit`fo$d`rmkt`fo d$; d$90${tfrm$`o$f}t$fr${mmf$iimf „€)k}dp omyt$90$`o{o „„2Df tim {tfrm ffr io `o{tr}kt`fo m`bm IRM„2i`ki fomp iot{ tf {tfrm fom iimffrd„2iod kio df `t `o tim IK- `o dmdfrp fr `o {mmf/„)mfkim`tp d$dmd „){tirt$d`{pitki ; `oi`b`t$ykt$omyt$b`t „d$90${tfrm$`o$f}t$fr${mmf$iimffrd„€)p$b`t {tfrm$90$ik$iimf „€)p$b`t {tfrm$90$ik$iimf „€)p$b`t {tfrm$90$dmd$iimf „€)p$b`t {tfrm$90${mmf$iimf „)mod$d`{pitki „)mfkim`tp `$dmd „„{tfrm$90${mmf$iimf„€)kimm {tfrm$90$dmd$iimf „€)pfpk$my}im d$i „€)k}dp {tfrm$90$ik$iimf „
„2[`dpmm ir`tidmt`k {}brf}t`om{/„„{}b$90$of$fmio{„€))d$9  {}b d$9 d$t „€))d$2  {}b d$2 d$r „€)k}dp$`f$b`t$kmmir pdp90$kirrp$0$b`t d$2 {}b$90$i „€))d$9  {}b d$9 )i$kfo{tiot 9  „{}b$90$i„€)pfpk$iftmr$omyt„€ )d$9  tr}okitm$tf$iimffrd d$9 „€))d$2  tr}okitm$tf$iimffrd d$2 „„`ok$90„€))d$2  idd d$2 )i$kfo{tiot 9  „€)k}dp$`f$b`t${mt pdp90$kirrp$0$b`t d$2 `ok$90$i „€))d$9  idd d$9 )i$kfo{tiot 9  „`ok$90$i„222666 Ommd{ tf kfdp}tm iod {ivm kirrp 0- kirrp 9 iod fvmrfmf fmio{/„€)pfpk$iftmr$omyt„€ )d$9  tr}okitm$tf$iimffrd d$9 „€))d$2  tr}okitm$tf$iimffrd d$2 „„dmk$90„€))d$2  {}b d$2 )i$kfo{tiot 9  „€)k}dp$`f$b`t$kmmir pdp90$kirrp$0$b`t d$2 `ok$90$i „€))d$9  idd d$9 )i$kfo{tiot 9  „dmk$90$i„222666 Ommd{ tf kfdp}tm iod {ivm kirrp 0- kirrp 9 iod fvmrfmf fmio{/„€)pfpk$iftmr$omyt„€ )d$9  tr}okitm$tf$iimffrd d$9 „€))d$2  tr}okitm$tf$iimffrd d$2 „
„2TROO- mtk/„„2PDP90$TM[T$DFD@F@KIT@FO {if}md bm tim 60 b`t{ ff tim fpkfdm/„2PDP90$TM[T$[F]RKM$B@T {if}md bm b`t 90 ff tim fpkfdm/„2PDP90$TM[T$[_IPPMD$B@T {if}md bm b`t 9 ff tim fpkfdm/„2PDP90$TM[T$KFOD@T@FO {if}md bm b`t{ 6 ff tim fpkfdm/„„ykt$90$tm{t„2Fmtki tim tm{t di{b frfd mffmkt`vm iddrm{{ fr dmdfrp/„€)d`{pitki pdp90$tm{t${f}rkm$b`t d$; d$90$tm{t${f}rkm „2[ip tim tm{t di{b/{ iimvm{ `f ipprfpr`itm/„€)k}dp$`f$b`t$kmmir$ykt$omyt pdp90$tm{t${ippmd$b`t d$; ykt$90$tm{t$9 „       ))d$9  d$t „€))d$t  d$r „€))d$r  d$9 „ykt$90$tm{t$9„2Fmtki tim IK tf bm tm{tmd/„€)kimm mfid$90$ik „2Irm iop di{bmd k`tp dodpo{o?„€++d$`  kdd d$; k$t „€++d$`  kdd d$; k${ „€+d`ppkt`k${`t$do{t pdp;0$topt$`odd`t`od d$0 d$;0$topt$`odd`t`od „       ++d$`  `o{ d$` k$` „;Dkpko pto{o dot `odtodtp `d K@$„€+d`ppkt`k pdp;0$topt$dod`o``kt`od d$0 d$;0$topt$dod`o``kt`od „„+oo`ko`tp d$dod „+ptk{t$d`ppkt`k ; `dk`k`t${`t$do{t$k`t „d$;0$topt$po{`o„€+p$k`t {`t$;0$topt$`ddod „€+p$k`t ookd$;0$dod$t „+odd$d`ppkt`k „+oo`ko`tp `$dod „„{`t$;0$topt$`ddod„€+pop`$koto{$do{t„€ +d${  d$o „€++d$t  k$po{o „„;Do``do tkotko{ to pk`p/ kdd dkpko do po$„;@koood t`tk +d`ppkt`k${`t$do{t pdp;0$topt$`odd`t`od d$0 d$;0$topt$`odd`t`od „;Tko tk`dd to topt `p tkotko{ D$@ `p dodpo{o$„„+oo`ko`tp d$dod „+ptk{t$d`ppkt`k ; 0 „d$;0$topt$`odd`t`od„€+{`t$;0$topt$; €;Do dot pk`p$„€+p$k`t {`t$;0$topt$pk`p$`o$0 „€+p$k`t {`t$;0$topt$pk`p$kotkpp „€+p$k`t {`t$;0$topt$pk`p$dot$0 „+odd$d`ppkt`k „+oo`ko`tp `$dod „„{`t$;0$topt$pk`p$dot$0„€+`dp${`t$do{t {`t$;0$topt$pk`p$kotkpp „€+pop`$o{ko d$` k$po{o „;;;??? T`oo tkkt to{k?„„{`t$;0$topt$pk`p$`o$0„€+pop`$dot$o{ko d$` k$po{o „{`t$;0$topt$pk`p$kotkpp„€+pop` +d$k  kdd d$k +k$`odptkdt ;  „„;@odpto kdd pto{o tko dot `odtodtp oo tko k``dokto{$„;@koood kp +d`ppkt`k pdp;0$topt$dod`o``kt`od d$0 d$;0$topt$dod`o``kt`od „„+oo`ko`tp d$dod „+ptk{t$d`ppkt`k ; `dk`k`t${`t$do{t$k`t „d$;0$topt$dod`o``kt`od„€+do{t$;0$`dpd „€+{`t$;0$topt$pot$po{o „€+{`t$;0$topt$`odpoododt „€+{`t$;0$topt$pot$odo „+odd$d`ppkt`k „+oo`ko`tp `$dod „„{`t$;0$topt$pot$po{o„€++d$;  kdd`k d$; k$t „€++d$;  kddca m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-complement
	((m-1) xor m-1 a-t)
	((m-2) xor m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-set-one
	((m-1) ior m-1 a-t)
	((m-2) ior m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

;Stack instructions

i-10-push
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

i-10-pop
	(call-xct-next load-10-ac)
       ((c-pdl-buffer-pointer-push) m-e)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) c-pdl-buffer-pointer-pop)
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)


i-10-popj
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
;Set the PC.
	((m-b) add m-r a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Decrement the halves of the AC.
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)

i-10-pushj
	(call load-10-ac)
	(call-xct-next get-10-pc-and-flags-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

;Byte instructions.

;PDP10-BP-POSITION and PDP10-BP-SIZE are needed.

i-10-ldb
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem)
;Shift it right so desired byte is on the bottom.
	((m-t) pdp10-bp-position m-3)
	(call shift-10-right)
;Depending on whether byte size is more than 18,
;we must truncate M-1, or clear M-1 and truncate M-2.
;If it's exactly 0 or 18, we must clear one or both, but not truncate.
	((m-t) pdp10-bp-size m-3)
	(jump-greater-than m-t (a-constant 18.) i-10-ldb-1)
	(jump-equal-xct-next m-t (a-constant 18.) i-10-ldb-store)
       ((m-1) a-zero)
	(jump-equal-xct-next m-t a-zero i-10-ldb-store-0)
       ((m-t) sub m-t (a-constant 1))
	((oa-reg-low) dpb m-t oal-bytl-1 a-zero)
	((m-2) byte-inst m-2 a-zero)
i-10-ldb-store
	(jump-xct-next next-10-insn)
       (call store-10-ac)

i-10-ldb-store-0
	((m-2) a-zero)
	(jump-xct-next next-10-insn)
       (call store-10-ac)

i-10-ldb-1
	((m-t) sub m-t (a-constant 19.))
	((oa-reg-low) dpb m-t oal-bytl-1 a-zero)
	((m-1) byte-inst m-1 a-zero)
	(jump-xct-next next-10-insn)
       (call store-10-ac)

i-10-ibp
	(call load-10-mem)
	((m-t) pdp10-bp-position m-1)
	((m-r) pdp10-bp-size m-1)
	((m-t) sub m-t a-r)
	(call-less-than m-t a-zero i-10-ibp-next-word)
	((m-1) dpb m-t pdp10-bp-position a-1)
	(jump-xct-next next-10-insn)
       (call store-10-mem)

i-10-ibp-next-word
	((m-1) add m-1 (a-constant 1))
	(popj-after-next (m-t) (a-constant 36.))
       ((m-t) sub m-t a-r)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 13 BYTE-SIZE 10 CREATION-DATE 23075640633 AUTHOR "RMS")   

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

;The simulated PDP10 flags, except for CARRY 0, CARRY 1 and OVERFLOW,
;are kept in A-10-FLAGS.  The flags can be used to help decode
;the reason why the microcode simulator exited.
;For example, the pdl overflow flag may be set.

(def-data-field pdp10-sign-bit 1 17.)
(def-data-field pdp10-carry-0-bit 1 18.)

(def-data-field pdp10-index-field 4 0)
(def-data-field pdp10-indirect-bit 1 4)
(def-data-field pdp10-index-and-indirect 5 0) ;Indirect bit and index reg number.
(def-data-field pdp10-ac-field 4 5)
(def-data-field pdp10-opcode 9 9)

;These bits distinguish between test insns, logical insns, halfword insns, io insns, etc.
(def-data-field pdp10-insn-class 3 15.) ;Distinguish logical vs halfword vs test, etc.

;For instructions which can be direct, immediate, to memory or to self (or both),
;these are the bits which say which one it is.
(def-data-field pdp10-operation-direction 2 9.)

;These bits distinguish CAI vs CAM vs JUMP vs SKIP vs AOJ vs AOS vs SOJ vs SOS.
(def-data-field pdp10-jump-subclass 3 12.)
;These bits control the jump condition of a CAI, CAM, etc.
(def-data-field pdp10-jump-condition 3 9.)

;This bit, if set, means source of halfword insn is the right half.
(def-data-field pdp10-halfword-fetch-right-bit 1 11.)
;This bit means destination is the right half.
(def-data-field pdp10-halfword-store-right-bit 1 14.)
;These bits say what to do with the other halfword.
(def-data-field pdp10-other-halfword-action 2 12.)

;These bits control what operation a logical instruction does.
;They are like arg 1 of BOOLE.
(def-data-field pdp10-logical-operation 4 11.)

;In a test instruction, this bit, if one, says mask comes from memory.
(def-data-field pdp10-test-source-bit 1 12.)
;This bit, if one, says swap the mask (whether from memory or from 0,,E)
(def-data-field pdp10-test-swapped-bit 1 9)
;These bits say when to skip.
(def-data-field pdp10-test-condition 2 10.)
;These bits say what to do to the selected bits in the accumulator.
(def-data-field pdp10-test-modification 2 13.)

;Components of PDP10 byte pointers.
(def-data-field pdp10-bp-position 6 12.)
(def-data-field pdp10-bp-size 6 6)

(locality a-mem)

a-10-flags (0)

(assign pdp10-overflow-flag 400000)
(assign pdp10-carry-0-flag 200000)
(assign pdp10-carry-1-flag 100000)
(assign pdp10-floating-overflow-flag 040000)
(assign pdp10-fpd-flag 020000)
(assign pdp10-user-mode-flag 010000)
(assign pdp10-floating-underflow-flag 000100)
(assign pdp10-no-divide-flag 000040)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Entry and exit.

;Call with (%pdp10-simulator <pc> <flags> <address of memory array>)
;It returns two values on the stack: the new pc and the new flags.
enter-10-simulator
	(misc-inst-entry %pdp10-simulator)
	((a-10-mem-0-left-addr) c-pdl-buffer-pointer-pop)
	((a-10-flags) c-pdl-buffer-pointer-pop)
	((m-e) c-pdl-buffer-pointer-pop)
	(jump jump-10-jump)	;Jump to the PC now in M-E.

exit-10-simulator
	(call get-10-pc-and-flags-t)	;Get flags in M-T, pc in M-R.
	((c-pdl-buffer-pointer-push) m-r)
	(popj)				;return flags to misc insn destination (push).

pdl-10-overflow
	((m-1) (a-constant pdp10-pdl-overflow-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump exit-10-simulator)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc and flags in internal accumulator (m-1 and m-2)
get-10-pc-and-flags
;;;???

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Get the pc and flags in other accumulator (m-t and m-r)
get-10-pc-and-flags
;;;???
	(popj-after-next
	 (m-r) sub m-b a-10-mem-0-leftaddr)
	((m-r) m+1 m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn-1)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then go to begin again to execute the instruction.
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(jump-xct-next eff-addr-comp)
       ((m-3) mask-field pdp10-opcode m-3 a-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-lsh
	(call load-10-ac-t)
	((m-1) dpb m-t ?? a-zero)
	((m-1) dpb m-r ?? a-1)
	((m-2) dpb m-t ?? a-zero)
	((m-2) dpb m-r ?? a-2)
	(call store-10-ac-t)
	(jump next-10-insn)

;Arithmetic Jump and Skip Instructions

xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

;Depending on type of instruction,
;we get our argument from somewhere
;and then supply one of these as I-ARG when we test the condition.
(assign cond-10-jump 0)
(assign cond-10-skip 1)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-ac-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
inc-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;AND, etc.

xct-10-logical
	(call load-10-ac)
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both)
	((m-c) pdp10-logical-operation m-3)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-1) setz m-1 a-t)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-2) setz m-2 a-r)
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

;TRNN, etc.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)
;Maybe store new contents in AC.
	(dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-10-test-source
	(p-bit xct-10-test-immed)
	(p-bit load-10-mem-t)
(end-dispatch)
(locality i-mem)

xct-10-test-immed
	(popj-after-next
	 (m-r) m-e)
	((m-t) a-zero)

;Decide whether to skip, and maybe do so.
;Called with (dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
;The thing to test is whether M-I is nonzero.

(locality d-mem)
(start-dispatch 2 0)
d-10-test-condition
	(xct-10-test-2)	;Do not skip.
	(p-bit xct-10-test-skip-if-0)
	(p-bit xct-10-test-skip-always)
	(p-bit xct-10-test-skip-not-0)
(end-dispatch)
(locality i-mem)

xct-10-test-skip-not-0
	(jump-xct-next xct-10-test-skip-always)
	(popj-equal m-i a-zero)
;;;??? Will that work?

xct-10-test-skip-if-0
	(popj-not-equal m-i a-zero)
xct-10-test-skip-always
	(popj (m-b) add m-b (a-constant 1))

;Compute and store the new contents of the accumulator.
;Called by (dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-10-test-modification
	(next-10-insn)
	(xct-10-test-set-zero)
	(xct-10-test-complement)
	(xct-10-test-set-one)
(end-dispatch)
(locality i-mem)

xct-10-test-set-zero
	((m-1) andca m-1 a-t)
	((m-2) andca m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-complement
	((m-1) xor m-1 a-t)
	((m-2) xor m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-set-one
	((m-1) ior m-1 a-t)
	((m-2) ior m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

;Stack instructions

i-10-push
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

i-10-pop
	(call-xct-next load-10-ac)
       ((c-pdl-buffer-pointer-push) m-e)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) c-pdl-buffer-pointer-pop)
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)


i-10-popj
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
;Set the PC.
	((m-b) add m-r a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Decrement the halves of the AC.
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)

i-10-pushj
	(call load-10-ac)
	(call-xct-next get-10-pc-and-flags-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

;Byte instructions.

i-10-ibp
	(call inc-10-bp)
	(jump next-10-insn

;Increment the byte pointer in the PDP-10 memory location
;addressed by M-E.  Store it back in that memory location.
inc-10-bp
	(call load-10-mem)
	((m-t) pdp10-bp-position m-1)
	((m-r) pdp10-bp-size m-1)
	((m-t) sub m-t a-r)
	(call-less-than m-t a-zero i-10-ibp-next-word)
	((m-1) dpb m-t pdp10-bp-position a-1)
	(jump store-10-mem)

i-10-ibp-next-word
	((m-1) add m-1 (a-constant 1))
	(popj-after-next (m-t) (a-constant 36.))
       ((m-t) sub m-t a-r)


i-10-ildb
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-ldb-0)

i-10-ldb
	(call load-10-mem)
i-10-ldb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Shift it right so desired byte is on the bottom.
	((m-c) pdp10-bp-position m-3)
	(call shift-10-right)
;Depending on whether byte size is more than 18,
;we must truncate M-1, or clear M-1 and truncate M-2.
;If it's exactly 0 or 18, we must clear one or both, but not truncate.
	((m-c) pdp10-bp-size m-3)
	(call truncate-10-byte)
	(jump-xct-next next-10-insn)
       (call store-10-ac)

;Truncate the PDP-10 quantity in the A register
;to the length specified in M-C.
truncate-10-byte
	(jump-greater-than m-c (a-constant 18.) truncate-10-byte-1)
	(popj-equal-xct-next m-c (a-constant 18.))
       ((m-1) a-zero)
	(jump-equal-xct-next m-c a-zero truncate-10-byte-0-length)
       ((m-c) sub m-c (a-constant 1))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-2) byte-inst m-2 a-zero)

truncate-10-byte-0-length
	(popj (m-2) a-zero)

truncate-10-byte-1
	((m-c) sub m-c (a-constant 19.))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-1) byte-inst m-1 a-zero)


i-10-idpb
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-dpb-0)

i-10-dpb
	(call load-10-mem)
i-10-dpb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem-t)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Now zero out the byte we want to replace.
 ;Load -1 into the A-register, and shift/truncate it to the byte we want.
	((m-1) a-minus-one)
	((m-2) a-minus-one)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
 ;Now clear that byte in the T register.
	((m-t) andca m-t a-1)
	((m-r) andca m-r a-1)
;Get the byte into A register, truncate, and shift into position.
	(call load-10-ac)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
;Merge it into T register.
	((m-t) ior m-t a-1)
	((m-r) ior m-r a-2)
;Store the result.
	(jump-xct-next next-10-insn)
       (call store-10-mem-t)

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 14 BYTE-SIZE 10 CREATION-DATE 23075640637 AUTHOR "RMS")

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

;The simulated PDP10 flags are kept in A-10-FLAGS.
;However, the CARRY 0, CARRY 1 and OVERFLOW flags can also
;be considered set if ...???
;GET-10-PC-AND-FLAGS-T merges those things into A-10-FLAGS
;before returning the flags.

(def-data-field pdp10-sign-bit 1 17.)
(def-data-field pdp10-carry-0-bit 1 18.)

(def-data-field pdp10-index-field 4 0)
(def-data-field pdp10-indirect-bit 1 4)
(def-data-field pdp10-index-and-indirect 5 0) ;Indirect bit and index reg number.
(def-data-field pdp10-ac-field 4 5)
(def-data-field pdp10-opcode 9 9)

;These bits distinguish between test insns, logical insns, halfword insns, io insns, etc.
(def-data-field pdp10-insn-class 3 15.) ;Distinguish logical vs halfword vs test, etc.

;For instructions which can be direct, immediate, to memory or to self (or both),
;these are the bits which say which one it is.
(def-data-field pdp10-operation-direction 2 9.)

;These bits distinguish CAI vs CAM vs JUMP vs SKIP vs AOJ vs AOS vs SOJ vs SOS.
(def-data-field pdp10-jump-subclass 3 12.)
;These bits control the jump condition of a CAI, CAM, etc.
(def-data-field pdp10-jump-condition 3 9.)

;This bit, if set, means source of halfword insn is the right half.
(def-data-field pdp10-halfword-fetch-right-bit 1 11.)
;This bit means destination is the right half.
(def-data-field pdp10-halfword-store-right-bit 1 14.)
;These bits say what to do with the other halfword.
(def-data-field pdp10-other-halfword-action 2 12.)

;These bits control what operation a logical instruction does.
;They are like arg 1 of BOOLE.
(def-data-field pdp10-logical-operation 4 11.)

;In a test instruction, this bit, if one, says mask comes from memory.
(def-data-field pdp10-test-source-bit 1 12.)
;This bit, if one, says swap the mask (whether from memory or from 0,,E)
(def-data-field pdp10-test-swapped-bit 1 9)
;These bits say when to skip.
(def-data-field pdp10-test-condition 2 10.)
;These bits say what to do to the selected bits in the accumulator.
(def-data-field pdp10-test-modification 2 13.)

;This bit set in a JRST instruction makes it a JRSTF.
(def-data-field pdp10-jrstf-bit 1 6)

;Components of PDP10 byte pointers.
(def-data-field pdp10-bp-position 6 12.)
(def-data-field pdp10-bp-size 6 6)

(locality a-mem)

a-10-flags (0)

(assign pdp10-overflow-flag 400000)
(assign pdp10-carry-0-flag 200000)
(assign pdp10-carry-1-flag 100000)
(assign pdp10-floating-overflow-flag 040000)
(assign pdp10-fpd-flag 020000)
(assign pdp10-user-mode-flag 010000)
(assign pdp10-floating-underflow-flag 000100)
(assign pdp10-no-divide-flag 000040)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) m-r)

;Entry and exit.

;Call with (%pdp10-simulator <pc> <flags> <address of memory array>)
;It returns two values on the stack: the new pc and the new flags.
enter-10-simulator
	(misc-inst-entry %pdp10-simulator)
	((a-10-mem-0-left-addr) c-pdl-buffer-pointer-pop)
	((a-10-flags) c-pdl-buffer-pointer-pop)
	((m-e) c-pdl-buffer-pointer-pop)
	(jump jump-10-jump)	;Jump to the PC now in M-E.

exit-10-simulator
	(call get-10-pc-and-flags-t)	;Get flags in M-T, pc in M-R.
	((c-pdl-buffer-pointer-push) m-r)
	(popj)				;return flags to misc insn destination (push).

pdl-10-overflow
	((m-1) (a-constant pdp10-pdl-overflow-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump exit-10-simulator)

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc and flags in internal accumulator (m-1 and m-2)
get-10-pc-and-flags
;;;???

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Get the pc and flags in other accumulator (m-t and m-r)
get-10-pc-and-flags
;;;???
	(popj-after-next
	 (m-r) sub m-b a-10-mem-0-leftaddr)
	((m-r) m+1 m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(start-dispatch 5 0)
d-10-index-and-indirect-not-first-time
	(xct-10-insn)
(repeat 17 (do-10-indexing-after-indirect))
	(do-10-indirect)
(repeat 17 (do-10-indexing-after-indirect))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit m-3 xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indexing on address field in M-E after indirection
;index register number in M-A.
;The difference is where we test the indirect bit.
do-10-indexing-after-indirect
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit m-1 xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then decide whether
;additional indirection or indexing is needed.
;We do not clobber M-3.  This is for the sake of JRSTF!
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(dispatch-xct-next pdp10-index-and-indirect m-3
	   d-10-index-and-indirect-not-first-time)
       ((m-a) pdp10-index-field m-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;Arithmetic Jump and Skip Instructions

xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

;Depending on type of instruction,
;we get our argument from somewhere
;and then supply one of these as I-ARG when we test the condition.
(assign cond-10-jump 0)
(assign cond-10-skip 1)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-ac-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit d$2 `ok$90$i „€))d$9  idd d$9 )i$kfo{tiot 9  „`ok$90$i„222666 Ommd{ tf kfdp}tm iod {ivm kirrp 0- kirrp 9 iod fvmrfmf fmio{/„€)pfpk$iftmr-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;AND, etc.

xct-10-logical
	(call load-10-ac)
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both)
	((m-c) pdp10-logical-operation m-3)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-1) setz m-1 a-t)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-2) setz m-2 a-r)
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

;TRNN, etc.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)
;Maybe store new contents in AC.
	(dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d= 1=uubu=bdssu�™(q=byu ysu= 1=uubu=y}}ud9�™(q=byu lqd= 1=}u}=u9�(und=dybqqush9�(lsqlyuh y=}u}9��ysu= 1=uubu=y}}ud�™(qqj=qfuus=nuyu�™ (}=s9 }=u9�™((}=u9 q={us9��*Dusydu fhuuhus u b{yq, qnd }qhbu d b.�*Sqllud fyuh (dybqqush=ysu=nuyu qdq 1=uubu=sndyuyn }=" d= 1=uubu=sndyuyn9�*Uhu uhynw u uubu yb fhuuhus ]=Y yb nn{us.��(lsqlyuh d=}u}9�(buqsu=dybqqush 3 19�d= 1=uubu=sndyuyn�™(ysu= 1=uubu=39™*D nu b{yq.�™(q=byu ysu= 1=uubu=b{yq=yf=19�™(q=byu ysu= 1=uubu=b{yq=qlfqhb9�™(q=byu ysu= 1=uubu=b{yq=nu=19�(und=dybqqush9�(lsqlyuh y=}u}9��ysu= 1=uubu=b{yq=nu=1�™(jd}q=ysu=nuyu ysu= 1=uubu=b{yq=qlfqhb9�™(qqj=u`dql }=y q={us9�***... Fyll uhqu fs{.��ysu= 1=uubu=b{yq=yf=1�™(qqj=nu=u`dql }=y q={us9�ysu= 1=uubu=b{yq=qlfqhb�™(qqj (}=b9 qdd }=b (q=snbuqnu  99��*S}qduu qnd busu uhu nuf snuunub f uhu qssd}dlqus.�*Sqllud bh (dybqqush qdq 1=uubu=}dyfysquyn }=" d= 1=uubu=}dyfysquyn9��(lsqlyuh d=}u}9�(buqsu=dybqqush 3 ynhybyu=ysu=nuyu=byu9�d= 1=uubu=}dyfysquyn�™(nuyu= 1=ynbn9�™(ysu= 1=uubu=buu={us9�™(ysu= 1=uubu=s}qlu}unu9�™(ysu= 1=uubu=buu=nu9�(und=dybqqush9�(lsqlyuh y=}u}9��ysu= 1=uubu=buu={us�™((}= 9 qndsq }=  q=u9�™((}=39 qndsq }=3 q=s9�™(jd}q=ysu=nuyu nuyu= 1=ynbn9�™(sqll busu= 1=qs9��ysu= 1=uubu=s}qlu}unu�™((}= 9 ys }=  q=u9�™((}=39 ys }=3 q=s9�™(jd}q=ysu=nuyu nuyu= 1=ynbn9�™(sqll busu= 1=qs9��ysu= 1=uubu=buu=nu�™((}= 9 ys }=  q=u9�™((}=39 ys }=3 q=s9�™(jd}q=ysu=nuyu nuyu= 1=ynbn9�™(sqll busu= 1=qs9��*Buqs{ ynbusdsuynb��y= 1=qdbh�™(sqll lqd= 1=qs9�™(sqll=ysu=nuyu lqd= 1=}u}=u9�       ((}= 9 qdd }=  (q=snbuqnu  99�™((}=39 qdd }=3 (q=snbuqnu  99�™((}= 9 usdnsquu=u=hqlffsd }= 9�™(sqll=ysu=nuyu busu= 1=qs9�       ((}=39 usdnsquu=u=hqlffsd }=39�™(sqll=ysu=nuyu busu= 1=}u}=u9�       ((}=u9 }=39�™(jd}q=nu=u`dql }=  q={us nuyu= 1=ynbn9�™(jd}q qdl= 1=wusflf9��y= 1=qq�™(sqll=ysu=nuyu lqd= 1=qs9�       ((s=qdl=bdffus=qynuus=qdbh9 }=u9�™(sqll=ysu=nuyu lqd= 1=}u}=u9�       ((}=u9 }=39�™(sqll=ysu=nuyu busu= 1=}u}=u9�       ((}=u9 s=qdl=bdffus=qynuus=qq9�™((}= 9 bdb }=  (q=snbuqnu  99�™((}=39 bdb }=3 (q=snbuqnu  99�™((}= 9 usdnsquu=u=hqlffsd }= 9�™((}=39 usdnsquu=u=hqlffsd }=39�™(sqll busu= 1=qs9�™(jd}q=nu=u`dql™}=  (q=snbuqnu = 9 nuyu= 1=ynbn9�™(jd}q qdl= 1=wusflf9���y= 1=qqj�™(sqll lqd= 1=qs9�™(sqll=ysu=nuyu lqd= 1=}u}=u9�       ((}=u9 }=39�*Buu uhu QS.�™((}=b9 qdd }=s q= 1=}u}=1=lufu=qdds9�™((}=b9 bdb (q=snbuqnu  99�*Dussu}unu uhu hqlwub f uhu QS.�™((}= 9 bdb }=  (q=snbuqnu  99�™((}=39 bdb }=3 (q=snbuqnu  99�™((}= 9 usdnsquu=u=hqlffsd }= 9�™((}=39 usdnsquu=u=hqlffsd }=39�™(sqll busu= 1=qs9�™(jd}q=nu=u`dql™}=  (q=snbuqnu = 9 nuyu= 1=ynbn9�™(jd}q qdl= 1=wusflf9��y= 1=qdbhj�™(sall load-10-ac)
	(call-xct-next get-10-pc-and-flags-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

;Byte instructions.

i-10-ibp
	(call inc-10-bp)
	(jump next-10-insn)


;Truncate the PDP-10 quantity in the A register
;to the length specified in M-C.
truncate-10-byte
	(jump-greater-than m-c (a-constant 18.) truncate-10-byte-1)
	(popj-equal-xct-next m-c (a-constant 18.))
       ((m-1) a-zero)
	(jump-equal-xct-next m-c a-zero truncate-10-byte-0-length)
       ((m-c) sub m-c (a-constant 1))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-2) byte-inst m-2 a-zero)

truncate-10-byte-0-length
	(popj (m-2) a-zero)

truncate-10-byte-1
	((m-c) sub m-c (a-constant 19.))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-1) byte-inst m-1 a-zero)


;Increment the byte pointer in the PDP-10 memory location
;addressed by M-E.  Store it back in that memory location.
inc-10-bp
	(call load-10-mem)
	((m-t) pdp10-bp-position m-1)
	((m-r) pdp10-bp-size m-1)
	((m-t) sub m-t a-r)
	(call-less-than m-t a-zero inc-10-bp-next-word)
	((m-1) dpb m-t pdp10-bp-position a-1)
	(jump store-10-mem)

inc-10-bp-next-word
	((m-1) add m-1 (a-constant 1))
	(popj-after-next (m-t) (a-constant 36.))
       ((m-t) sub m-t a-r)

i-10-ildb
	(jump-if-bit-set pdp10-fpd-flag a-10-flags i-10-ldb)
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-ldb-0)

i-10-ldb
	(call load-10-mem)
i-10-ldb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Shift it right so desired byte is on the bottom.
	((m-c) pdp10-bp-position m-3)
	(call shift-10-right)
;Depending on whether byte size is more than 18,
;we must truncate M-1, or clear M-1 and truncate M-2.
;If it's exactly 0 or 18, we must clear one or both, but not truncate.
	((m-c) pdp10-bp-size m-3)
	(call truncate-10-byte)
	(jump-xct-next next-10-insn)
       (call store-10-ac)

i-10-idpb
	(jump-if-bit-set pdp10-fpd-flag a-10-flags i-10-dpb)
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-dpb-0)

i-10-dpb
	(call load-10-mem)
i-10-dpb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem-t)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Now zero out the byte we want to replace.
 ;Load -1 into the A-register, and shift/truncate it to the byte we want.
	((m-1) a-minus-one)
	((m-2) a-minus-one)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
 ;Now clear that byte in the T register.
	((m-t) andca m-t a-1)
	((m-r) andca m-r a-1)
;Get the byte into A register, truncate, and shift into position.
	(call load-10-ac)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
;Merge it into T register.
	((m-t) ior m-t a-1)
	((m-r) ior m-r a-2)
;Store the result.
	(jump-xct-next next-10-insn)
       (call store-10-mem-t)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-jrst
;If not JRSTF, just jump.
	(jump-if-bit-clear pdp10-jrstf-bit m-3 jump-10-jump)
;We must reconstruct the flags to restore!
;The result of any indirection is still in M-1,
;but any indexing which followed it was only done for the right half (M-E).
;So we must do it now for the left half.
;Also, if there was no indirection, we must initialize M-1 to zero.
	(jump-if-bit-set pdp10-indirect-bit m-3 i-10-jrstf-1)
	((m-1) a-zero)
i-10-jrstf-1
	((m-a) pdp10-index-field m-3)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) add m-1 a-10-ac-0-left)
	((a-10-flags) mask-field m-1 a-zero)
	(jump jump-10-jump)

i-10-jsr
	(call get-10-pc-and-flags-t)
	(call store-10-mem-t)
	(jump-xct-next jump-10-jump)
       ((m-e) add m-e (a-constant 1))

i-10-jsp
	(call get-10-pc-and-flags-t)
	(jump-xct-next jump-10-jump)
       (call store-10-ac-t)

i-10-jsa
	(call load-10-ac)
	(call store-10-mem)
	(call-xct-next get-10-pc)
       ((m-1) m-e)
	(call store-10-ac)
	(jump-xct-next jump-10-jump)
	((m-e) add m-e (a-constant 1))

i-10-jra
	((m-t) m-e)
	(call load-10-ac)
	((m-e) m-1)
	(call load-10-mem)
	(call store-10-ac)
	((m-e) m-t)
	(jump jump-10-jump)	
	
;Shift instructions.
i-10-lsh
	(call load-10-ac)
	(jump-greater-than-or-equal m-e a-zero i-10-lsh-left)
	((m-c) sub m-zero a-e)
	(call shift-10-right)
       ((m-c) pdp10-shift-count m-c)
	(call store-10-ac)
	(jump next-10-insn)

i-10-lsh-left
	(call shift-10-left)
       ((m-c) pdp10-shift-count m-e)
	(call store-10-ac)
	(jump next-10-insn)

i-10-ash
	(call load-10-ac)
	(jump-greater-than-or-equal m-e a-zero i-10-lsh-left)
	((m-c) sub m-zero a-e)
	(call arith-shift-10-right)
       ((m-c) pdp10-shift-count m-c)
	(call store-10-ac)
	(jump next-10-insn)

;;;??? No point in writing the rest until I can write
;SHIFT-10-LEFT, etc.

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 15 BYTE-SIZE 10 CREATION-DATE 23075640645 AUTHOR "RMS")    

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.

;The simulated PDP10 flags are kept in A-10-FLAGS.
;However, the CARRY 0, CARRY 1 and OVERFLOW flags can also
;be considered set if ...???
;GET-10-PC-AND-FLAGS-T merges those things into A-10-FLAGS
;before returning the flags.

(def-data-field pdp10-sign-bit 1 17.)
(def-data-field pdp10-carry-0-bit 1 18.)

(def-data-field pdp10-index-field 4 0)
(def-data-field pdp10-indirect-bit 1 4)
(def-data-field pdp10-index-and-indirect 5 0) ;Indirect bit and index reg number.
(def-data-field pdp10-ac-field 4 5)
(def-data-field pdp10-opcode 9 9)

;These bits distinguish between test insns, logical insns, halfword insns, io insns, etc.
(def-data-field pdp10-insn-class 3 15.) ;Distinguish logical vs halfword vs test, etc.

;For instructions which can be direct, immediate, to memory or to self (or both),
;these are the bits which say which one it is.
(def-data-field pdp10-operation-direction 2 9.)

;These bits distinguish CAI vs CAM vs JUMP vs SKIP vs AOJ vs AOS vs SOJ vs SOS.
(def-data-field pdp10-jump-subclass 3 12.)
;These bits control the jump condition of a CAI, CAM, etc.
(def-data-field pdp10-jump-condition 3 9.)

;This bit, if set, means source of halfword insn is the right half.
(def-data-field pdp10-halfword-fetch-right-bit 1 11.)
;This bit means destination is the right half.
(def-data-field pdp10-halfword-store-right-bit 1 14.)
;These bits say what to do with the other halfword.
(def-data-field pdp10-other-halfword-action 2 12.)

;These bits control what operation a logical instruction does.
;They are like arg 1 of BOOLE.
(def-data-field pdp10-logical-operation 4 11.)

;In a test instruction, this bit, if one, says mask comes from memory.
(def-data-field pdp10-test-source-bit 1 12.)
;This bit, if one, says swap the mask (whether from memory or from 0,,E)
(def-data-field pdp10-test-swapped-bit 1 9)
;These bits say when to skip.
(def-data-field pdp10-test-condition 2 10.)
;These bits say what to do to the selected bits in the accumulator.
(def-data-field pdp10-test-modification 2 13.)

;This bit set in a JRST instruction makes it a JRSTF.
(def-data-field pdp10-jrstf-bit 1 6)

;Components of PDP10 byte pointers.
(def-data-field pdp10-bp-position 6 12.)
(def-data-field pdp10-bp-size 6 6)

(locality a-mem)

a-10-flags (0)

(assign pdp10-overflow-flag 400000)
(assign pdp10-carry-0-flag 200000)
(assign pdp10-carry-1-flag 100000)
(assign pdp10-floating-overflow-flag 040000)
(assign pdp10-fpd-flag 020000)
(assign pdp10-user-mode-flag 010000)
(assign pdp10-floating-underflow-flag 000100)
(assign pdp10-no-divide-flag 000040)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store routines automatically zero out the unused bits of
;the Qs being stored.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Store routines automatically zero out the unused bits of
;the Qs being stored.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) truncate-to-halfword m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) truncate-to-halfword m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) truncate-to-halfword m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) truncate-to-halfword m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-r)

;Entry and exit.

;Call with (%pdp10-simulator data-array)
;It returns NIL, having made changes in the data-array.
enter-10-simulator
	(misc-inst-entry %pdp10-simulator)
	(call gahdra)			;Pop and decode array.
	(call-if-bit-set (lisp-byte %%array-displaced-bit) m-b trap)
		(error-table argtyp non-displaced-array m-a 0)
	((m-b) selective-deposit m-b (lisp-byte %%array-type-field) a-zero)
	(call-not-equal m-b (a-constant (eval art-q)) trap)
		(error-table argtyp art-q-array m-a 0)
	(call-not-equal m-d (a-constant 1) trap)
		(error-table array-number-dimensions m-d 1 m-a)
	;; now we have the array in M-A (origin in M-E, length in M-S)
	(call-less-than m-s (a-constant data-array-length) trap)
		(error-table argtyp reasonable-size-array m-a 0)
;Load the PDP-10 accumulators from the data array.
	((m-a) a-zero)
	((vma) m-e)
	((a-10-data-array-origin) m-e)
enter-10-simulator-1
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((m-1) truncate-to-halfword read-memory-data)
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((m-2) truncate-to-halfword read-memory-data)
	(call-xct-next store-10-ac)
       ((m-a) add m-a (a-constant 1))
	(jump-less-than m-a (a-constant 20) enter-10-simulator-1)

;Fetch the PC and flags.
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((m-e) truncate-to-halfword read-memory-data)
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((a-10-flags) truncate-to-halfword read-memory-data)
;Fetch the address of PDP-10 memory.
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((a-10-mem-0-left-addr) truncate-to-halfword read-memory-data)
	((m-1) truncate-to-halfword read-memory-data)
	((a-10-mem-0-right-addr) add m-1 (a-constant 1000000))
	(jump jump-10-jump)	;Jump to the PC now in M-E.

(assign exit-10-pdl-overflow 1)
pdl-10-overflow
	((m-c) (a-constant exit-10-pdl-overflow))

exit-10-simulator
;M-C has code indicating exit condition.
;Store the ACs back into the data array.	
	((vma) a-10-data-array-origin)
	((m-a) a-zero)
exit-10-simulator-1
	(call load-10-ac)
		
	((write-memory-data) dpb m-1 q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
	((write-memory-data) dpb m-2 q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
	((m-a) add m-a (a-constant 1))
	(jump-less-than m-a (a-constant 20) exit-10-simulator-1)

;Store pc and flags via T register.
	(call get-10-pc-and-flags-t)	;Get flags in M-T, pc in M-R.
	((write-memory-data) dpb m-t q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
	((write-memory-data) dpb m-r q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
;Return the exit condition code, as a fixnum.
	(popj (m-t) dpb m-c q-pointer (a-constant (byte-value q-data-type dtp-fix)))

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc and flags in internal accumulator (m-1 and m-2)
get-10-pc-and-flags
;;;???

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Get the pc and flags in other accumulator (m-t and m-r)
get-10-pc-and-flags
;;;???
	(popj-after-next
	 (m-r) sub m-b a-10-mem-0-leftaddr)
	((m-r) m+1 m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(start-dispatch 5 0)
d-10-index-and-indirect-not-first-time
	(xct-10-insn)
(repeat 17 (do-10-indexing-after-indirect))
	(do-10-indirect)
(repeat 17 (do-10-indexing-after-indirect))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit m-3 xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indexing on address field in M-E after indirection
;index register number in M-A.
;The difference is where we test the indirect bit.
do-10-indexing-after-indirect
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit m-1 xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then decide whether
;additional indirection or indexing is needed.
;We do not clobber M-3.  This is for the sake of JRSTF!
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(dispatch-xct-next pdp10-index-and-indirect m-3
	   d-10-index-and-indirect-not-first-time)
       ((m-a) pdp10-index-field m-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;Arithmetic Jump and Skip Instructions

xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

;Depending on type of instruction,
;we get our argument from somewhere
;and then supply one of these as I-ARG when we test the condition.
(assign cond-10-jump 0)
(assign cond-10-skip 1)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-ac-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
inc-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;AND, etc.

xct-10-logical
	(call load-10-ac)
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both)
	((m-c) pdp10-logical-operation m-3)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-1) setz m-1 a-t)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-2) setz m-2 a-r)
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

;TRNN, etc.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)
;Maybe store new contents in AC.
	(dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-10-test-source
	(p-bit xct-10-test-immed)
	(p-bit load-10-mem-t)
(end-dispatch)
(locality i-mem)

xct-10-test-immed
	(popj-after-next
	 (m-r) m-e)
	((m-t) a-zero)

;Decide whether to skip, and maybe do so.
;Called with (dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
;The thing to test is whether M-I is nonzero.

(locality d-mem)
(start-dispatch 2 0)
d-10-test-condition
	(xct-10-test-2)	;Do not skip.
	(p-bit xct-10-test-skip-if-0)
	(p-bit xct-10-test-skip-always)
	(p-bit xct-10-test-skip-not-0)
(end-dispatch)
(locality i-mem)

xct-10-test-skip-not-0
	(jump-xct-next xct-10-test-skip-always)
	(popj-equal m-i a-zero)
;;;??? Will that work?

xct-10-test-skip-if-0
	(popj-not-equal m-i a-zero)
xct-10-test-skip-always
	(popj (m-b) add m-b (a-constant 1))

;Compute and store the new contents of the accumulator.
;Called by (dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-10-test-modification
	(next-10-insn)
	(xct-10-test-set-zero)
	(xct-10-test-complement)
	(xct-10-test-set-one)
(end-dispatch)
(locality i-mem)

xct-10-test-set-zero
	((m-1) andca m-1 a-t)
	((m-2) andca m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-complement
	((m-1) xor m-1 a-t)
	((m-2) xor m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-set-one
	((m-1) ior m-1 a-t)
	((m-2) ior m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

;Stack instructions

i-10-push
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

i-10-pop
	(call-xct-next load-10-ac)
       ((c-pdl-buffer-pointer-push) m-e)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) c-pdl-buffer-pointer-pop)
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)


i-10-popj
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
;Set the PC.
	((m-b) add m-r a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Decrement the halves of the AC.
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)

i-10-pushj
	(call load-10-ac)
	(call-xct-next get-10-pc-and-flags-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

;Byte instructions.

i-10-ibp
	(call inc-10-bp)
	(jump next-10-insn)


;Truncate the PDP-10 quantity in the A register
;to the length specified in M-C.
truncate-10-byte
	(jump-greater-than m-c (a-constant 18.) truncate-10-byte-1)
	(popj-equal-xct-next m-c (a-constant 18.))
       ((m-1) a-zero)
	(jump-equal-xct-next m-c a-zero truncate-10-byte-0-length)
       ((m-c) sub m-c (a-constant 1))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-2) byte-inst m-2 a-zero)

truncate-10-byte-0-length
	(popj (m-2) a-zero)

truncate-10-byte-1
	((m-c) sub m-c (a-constant 19.))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-1) byte-inst m-1 a-zero)


;Increment the byte pointer in the PDP-10 memory location
;addressed by M-E.  Store it back in that memory location.
inc-10-bp
	(call load-10-mem)
	((m-t) pdp10-bp-position m-1)
	((m-r) pdp10-bp-size m-1)
	((m-t) sub m-t a-r)
	(call-less-than m-t a-zero inc-10-bp-next-word)
	((m-1) dpb m-t pdp10-bp-position a-1)
	(jump store-10-mem)

inc-10-bp-next-word
	((m-1) add m-1 (a-constant 1))
	(popj-after-next (m-t) (a-constant 36.))
       ((m-t) sub m-t a-r)

i-10-ildb
	(jump-if-bit-set pdp10-fpd-flag a-10-flags i-10-ldb)
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-ldb-0)

i-10-ldb
	(call load-10-mem)
i-10-ldb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Shift it right so desired byte is on the bottom.
	((m-c) pdp10-bp-position m-3)
	(call shift-10-right)
;Depending on whether byte size is more than 18,
;we must truncate M-1, or clear M-1 and truncate M-2.
;If it's exactly 0 or 18, we must clear one or both, but not truncate.
	((m-c) pdp10-bp-size m-3)
	(call truncate-10-byte)
	(jump-xct-next next-10-insn)
       (call store-10-ac)

i-10-idpb
	(jump-if-bit-set pdp10-fpd-flag a-10-flags i-10-dpb)
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-dpb-0)

i-10-dpb
	(call load-10-mem)
i-10-dpb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem-t)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Now zero out the byte we want to replace.
 ;Load -1 into the A-register, and shift/truncate it to the byte we want.
	((m-1) a-minus-one)
	((m-2) a-minus-one)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
 ;Now clear that byte in the T register.
	((m-t) andca m-t a-1)
	((m-r) andca m-r a-1)
;Get the byte into A register, truncate, and shift into position.
	(call load-10-ac)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
;Merge it into T register.
	((m-t) ior m-t a-1)
	((m-r) ior m-r a-2)
;Store the result.
	(jump-xct-next next-10-insn)
       (call store-10-mem-t)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-jrst
;If not JRSTF, just jump.
	(jump-if-bit-clear pdp10-jrstf-bit m-3 jump-10-jump)
;We must reconstruct the flags to restore!
;The result of any indirection is still in M-1,
;but any indexing which followed it was only done for the right half (M-E).
;So we must do it now for the left half.
;Also, if there was no indirection, we must initialize M-1 to zero.
	(jump-if-bit-set pdp10-indirect-bit m-3 i-10-jrstf-1)
	((m-1) a-zero)
i-10-jrstf-1
	((m-a) pdp10-index-field m-3)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) add m-1 a-10-ac-0-left)
	((a-10-flags) mask-field m-1 a-zero)
	(jump jump-10-jump)

i-10-jsr
	(call get-10-pc-and-flags-t)
	(call store-10-mem-t)
	(jump-xct-next jump-10-jump)
       ((m-e) add m-e (a-constant 1))

i-10-jsp
	(call get-10-pc-and-flags-t)
	(jump-xct-next jump-10-jump)
       (call store-10-ac-t)

i-10-jsa
	(call load-10-ac)
	(call store-10-mem)
	(call-xct-next get-10-pc)
       ((m-1) m-e)
	(call store-10-ac)
	(jump-xct-next jump-10-jump)
	((m-e) add m-e (a-constant 1))

i-10-jra
	((m-t) m-e)
	(call load-10-ac)
	((m-e) m-1)
	(call load-10-mem)
	(call store-10-ac)
	((m-e) m-t)
	(jump jump-10-jump)	
	
;Shift instructions.
i-10-lsh
	(call load-10-ac)
	(jump-greater-than-or-equal m-e a-zero i-10-lsh-left)
	((m-c) sub m-zero a-e)
	(call shift-10-right)
       ((m-c) pdp10-shift-count m-c)
	(call store-10-ac)
	(jump next-10-insn)

i-10-lsh-left
	(call shift-10-left)
       ((m-c) pdp10-shift-count m-e)
	(call store-10-ac)
	(jump next-10-insn)

i-10-ash
	(call load-10-ac)
	(jump-greater-than-or-equal m-e a-zero i-10-lsh-left)
	((m-c) sub m-zero a-e)
	(call arith-shift-10-right)
       ((m-c) pdp10-shift-count m-c)
	(call store-10-ac)
	(jump next-10-insn)

;;;??? No point in writing the rest until I can write
;SHIFT-10-LEFT, etc.

* LMFL(DIRECTORY "RMS" NAME "PDP10" TYPE "LISP" VERSION 16 BYTE-SIZE 10 CREATION-DATE 23075640653 AUTHOR "RMS")    

;PDP-10 simulator microcode

;The simulator uses an internal accumulator for its arithmetic
;and most of its data transfers.
;This internal accumulator consists of M-1 and M-2.
;M-1 holds the left half of the 36-bit quantity and M-2 the right half.

;The other argument of arithmetic operations goes in
;the T register, composed of M-T and M-R.

;Instructions are executed out of the instruction register,
;which occupies M-3 and M-E.

;The AC field of the instruction is standardly placed in M-A,
;and the effective address is computed in M-E.

;The simulated PC lives in M-B; actually, that contains
;one less than the Q address of the left halfword of the next instruction.
;Jump instructions and PC saving instructions convert
;between this form of quantity and a pdp-10 address.
;M-Q contains the count of instructions to execute before it is time to return.

;The simulated PDP10 flags are kept in A-10-FLAGS.
;However, the CARRY 0, CARRY 1 and OVERFLOW flags can also
;be considered set if ...???
;GET-10-PC-AND-FLAGS-T merges those things into A-10-FLAGS
;before returning the flags.

(def-data-field pdp10-sign-bit 1 17.)
(def-data-field pdp10-carry-0-bit 1 18.)

(def-data-field pdp10-index-field 4 0)
(def-data-field pdp10-indirect-bit 1 4)
(def-data-field pdp10-index-and-indirect 5 0) ;Indirect bit and index reg number.
(def-data-field pdp10-ac-field 4 5)
(def-data-field pdp10-opcode 9 9)

;These bits distinguish between test insns, logical insns, halfword insns, io insns, etc.
(def-data-field pdp10-insn-class 3 15.) ;Distinguish logical vs halfword vs test, etc.

;For instructions which can be direct, immediate, to memory or to self (or both),
;these are the bits which say which one it is.
(def-data-field pdp10-operation-direction 2 9.)

;These bits distinguish CAI vs CAM vs JUMP vs SKIP vs AOJ vs AOS vs SOJ vs SOS.
(def-data-field pdp10-jump-subclass 3 12.)
;These bits control the jump condition of a CAI, CAM, etc.
(def-data-field pdp10-jump-condition 3 9.)

;This bit, if set, means source of halfword insn is the right half.
(def-data-field pdp10-halfword-fetch-right-bit 1 11.)
;This bit means destination is the right half.
(def-data-field pdp10-halfword-store-right-bit 1 14.)
;These bits say what to do with the other halfword.
(def-data-field pdp10-other-halfword-action 2 12.)

;These bits control what operation a logical instruction does.
;They are like arg 1 of BOOLE.
(def-data-field pdp10-logical-operation 4 11.)

;In a test instruction, this bit, if one, says mask comes from memory.
(def-data-field pdp10-test-source-bit 1 12.)
;This bit, if one, says swap the mask (whether from memory or from 0,,E)
(def-data-field pdp10-test-swapped-bit 1 9)
;These bits say when to skip.
(def-data-field pdp10-test-condition 2 10.)
;These bits say what to do to the selected bits in the accumulator.
(def-data-field pdp10-test-modification 2 13.)

;This bit set in a JRST instruction makes it a JRSTF.
(def-data-field pdp10-jrstf-bit 1 6)

;Components of PDP10 byte pointers.
(def-data-field pdp10-bp-position 6 12.)
(def-data-field pdp10-bp-size 6 6)

(locality a-mem)

;Address of first data word of the array in which
;the AC contents, PC and flags were passed,
;so we can store them back when we exit.
a-10-data-array-origin (0)

a-10-flags (0)

(assign pdp10-overflow-flag 400000)
(assign pdp10-carry-0-flag 200000)
(assign pdp10-carry-1-flag 100000)
(assign pdp10-floating-overflow-flag 040000)
(assign pdp10-fpd-flag 020000)
(assign pdp10-user-mode-flag 010000)
(assign pdp10-floating-underflow-flag 000100)
(assign pdp10-no-divide-flag 000040)

(modulo 2)	;So halfword instructions can choose which half!

;Address of Q containing the left half of simulated memory location 0.
;The left halves of all PDP-10 memory words live in consecutive Qs.
a-10-mem-0-left-addr (0)

;Address of Q containing the right half of simulated memory location 0.
;The right halves of all PDP-10 memory words live in consecutive Qs,
;immediately following the left halves.
;Thus, this address is always 1000000 more than that in a-10-mem-0-left-addr.
a-10-mem-0-right-addr (0)

;Address of left half of memory location 20,
;used for testing the PC to see whether points at an AC.
a-10-mem-20-left-addr (0)

;40 here so halfword instructions can choose which half!
(modulo 40)

;These are the left halves of the pdp-10's simulated accumulators.
a-10-ac-0-left (0)

(modulo 20)

;These are the right halves.
a-10-ac-0-right (0)

(modulo 20)

(locality i-mem)

;Load and store simulated accumulators (AC number in M-A)
;from the internal accumulator and the T register.

;Store routines automatically zero out the unused bits of
;the Qs being stored.

;Store the internal accumulator into the simulated accumulator
;whose number is in M-A.
store-10-ac
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-2)

;Load the simulated accumulator whose number is in M-A
;into the internal accumulator.
load-10-ac
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the T register into the simulated accumulator
;whose number is in M-A.
store-10-ac-t
	((oa-reg-low) dpb m-a oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-a oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-r)

;Load the simulated accumulator whose number is in M-A
;into the T register.
load-10-ac-t
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-a oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Load and store main memory (address in M-E)
;from the internal accumulator and the T register.

;Store routines automatically zero out the unused bits of
;the Qs being stored.

;Load the simulated memory location whose number is in M-E
;into the internal accumulator.
load-10-mem
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-1) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-ac-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-1) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-2) a-10-ac-0-right)

;Store the internal accumulator into the simulated memory location
;whose address is in M-E.
store-10-mem
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) truncate-to-halfword m-1)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) truncate-to-halfword m-2)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-1)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-2)

;Load the simulated memory location whose number is in M-E
;into the T register.
load-10-mem-t
	(jump-less-than m-e (a-constant 20)
			load-10-ac-m-e)	;Check for ACs referenced as memory.
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	((m-t) read-memory-data)
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-r) read-memory-data)

load-10-ac-t-m-e
	((oa-reg-high) dpb m-e oah-a-src a-zero)
	((m-t) a-10-ac-0-left)
	(popj-after-next
	 (oa-reg-high) dpb m-e oah-a-src a-zero)
       ((m-r) a-10-ac-0-right)

;Store the T register into the simulated memory location
;whose address is in M-E.
store-10-mem-t
	(jump-less-than m-e (a-constant 20)
			store-10-ac-m-e)	;Check for ACs referenced as memory.
	((write-memory-data) truncate-to-halfword m-t)
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	((write-memory-data) truncate-to-halfword m-r)
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

store-10-ac-t-m-e
	((oa-reg-low) dpb m-e oal-a-dest a-zero)
	((a-10-ac-0-left) truncate-to-halfword m-t)
	(popf-after-next
	 (oa-reg-low) dpb m-e oal-a-dest a-zero)
       ((a-10-ac-0-right) truncate-to-halfword m-r)

;Entry and exit.

;Call with (%pdp10-simulator data-array)
;It returns NIL, having made changes in the data-array.
enter-10-simulator
	(misc-inst-entry %pdp10-simulator)
	(call gahdra)			;Pop and decode array.
	(call-if-bit-set (lisp-byte %%array-displaced-bit) m-b trap)
		(error-table argtyp non-displaced-array m-a 0)
	((m-b) selective-deposit m-b (lisp-byte %%array-type-field) a-zero)
	(call-not-equal m-b (a-constant (eval art-q)) trap)
		(error-table argtyp art-q-array m-a 0)
	(call-not-equal m-d (a-constant 1) trap)
		(error-table array-number-dimensions m-d 1 m-a)
	;; now we have the array in M-A (origin in M-E, length in M-S)
	(call-less-than m-s (a-constant data-array-length) trap)
		(error-table argtyp reasonable-size-array m-a 0)
;Load the PDP-10 accumulators from the data array.
	((m-a) a-zero)
	((vma) m-e)
	((a-10-data-array-origin) m-e)
enter-10-simulator-1
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((m-1) truncate-to-halfword read-memory-data)
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((m-2) truncate-to-halfword read-memory-data)
	(call-xct-next store-10-ac)
       ((m-a) add m-a (a-constant 1))
	(jump-less-than m-a (a-constant 20) enter-10-simulator-1)

;Fetch the PC and flags and instruction count.
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((c-pdl-buffer-pointer-push) truncate-to-halfword read-memory-data)
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((a-10-flags) truncate-to-halfword read-memory-data)
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((m-q) q-pointer read-memory-data)
;Fetch the address of PDP-10 memory.
	((vma-start-read) add vma (a-constant 1))
	(check-page-read)
	((m-a) read-memory-data)
	(call gahdr)
	((a-10-mem-0-left-addr) m-e)
	((a-10-mem-0-right-addr) add m-e (a-constant 1000000))
	((a-10-mem-20-left-addr) add m-e (a-constant 20))
	((m-e) c-pdl-buffer-pointer-pop)
	(jump jump-10-jump)	;Jump to the PC now in M-E.

;Exit codes returned as value from call to %PDP10-SIMULATOR.

(assign exit-10-sequence-break 0)
; With that code, the caller should loop around and start it up again.

(assign exit-10-pdl-overflow 1)
(assign exit-10-system-call 2)
(assign exit-10-instruction-count 3)

pdl-10-overflow
	((m-c) (a-constant exit-10-pdl-overflow))
	(jump exit-10-simulator)

enough-10-insns-done
	((m-c) (a-constant exit-10-instruction-count))
	(jump exit-10-simulator)

exit-10-simulator
;M-C has code indicating exit condition.
;Store the ACs back into the data array.	
	((vma) a-10-data-array-origin)
	((m-a) a-zero)
exit-10-simulator-1
	(call load-10-ac)
		
	((write-memory-data) dpb m-1 q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
	((write-memory-data) dpb m-2 q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
	((m-a) add m-a (a-constant 1))
	(jump-less-than m-a (a-constant 20) exit-10-simulator-1)

;Store pc and flags via T register.
	(call get-10-pc-and-flags-t)	;Get flags in M-T, pc in M-R.
	((write-memory-data) dpb m-t q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
	((write-memory-data) dpb m-r q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
;Store remaining instruction count
	((write-memory-data) dpb m-q q-pointer (a-constant (byte-value q-data-type dtp-fix)))
	((vma-start-write) add vma (a-constant 1))
	(check-page-write)
;Return the exit condition code, as a fixnum.
	(popj (m-t) dpb m-c q-pointer (a-constant (byte-value q-data-type dtp-fix)))

;Set the simulated pc from a pdp-10 format pc in M-2.
set-10-pc
	(popj-after-next
	 (m-b) add m-2 (a-constant -1))
       ((m-b) add m-b a-10-mem-0-left-addr)

;Get the pc and flags in internal accumulator (m-1 and m-2)
get-10-pc-and-flags
;;;???

;Get the pc in pdp-10 form in M-2.
get-10-pc
	(popj-after-next
	 (m-2) sub m-b a-10-mem-0-leftaddr)
	((m-2) m+1 m-2)

;Get the pc and flags in other accumulator (m-t and m-r)
get-10-pc-and-flags
;;;???
	(popj-after-next
	 (m-r) sub m-b a-10-mem-0-leftaddr)
	((m-r) m+1 m-r)

;Come here to jump to effective address and execute next instruction.
jump-10-jump
	((m-b) add m-e a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Loop point for executing the next pdp-10 instruction.
next-10-insn
	(jump-less-than-or-equal-xct-next m-q (a-constant 0) enough-10-insns-done)
       ((m-q) sub m-q (a-constant 1))
	(jump-less-than m-b a-10-mem-20-addr xct-10-ac) ;Check for ACs referenced as memory.
	((vma-start-read m-b) m+1 m-b)	;Increment pc and fetch lh of insn.
	(check-page-read)
	((m-3) read-memory-data)
	((vma-start-read) add m-b (a-constant 1000000))
	(check-page-read)
	((m-e) read-memory-data)
;Compute the effective address in M-E
;for the instruction in the instruction register (M-3, M-E).
eff-addr-comp
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)

;Fetch the next instruction from an accumulator.
xct-10-ac
	(call get-10-pc)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-3) a-10-ac-0-left)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	(jump-xct-next eff-addr-comp)
       ((m-e) a-10-ac-0-right)

(locality d-mem)

(start-dispatch 5 0)
d-10-index-and-indirect
	(xct-10-insn)
(repeat 17 (do-10-indexing))
	(do-10-indirect)
(repeat 17 (do-10-indexing))
(end-dispatch)

(start-dispatch 5 0)
d-10-index-and-indirect-not-first-time
	(xct-10-insn)
(repeat 17 (do-10-indexing-after-indirect))
	(do-10-indirect)
(repeat 17 (do-10-indexing-after-indirect))
(end-dispatch)

(locality i-mem)

;Perform indexing on address field in M-E
;with index register number in M-A.
do-10-indexing
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit m-3 xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indexing on address field in M-E after indirection
;index register number in M-A.
;The difference is where we test the indirect bit.
do-10-indexing-after-indirect
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-e) add m-e a-10-ac-0-right)
	(jump-if-bit-clear-xct-next pdp10-indirect-bit m-1 xct-10-insn)
       ((m-e) truncate-to-halfword m-e)

;Perform indirection, and merge the indirect pointer
;into the instruction register.  Then decide whether
;additional indirection or indexing is needed.
;We do not clobber M-3.  This is for the sake of JRSTF!
do-10-indirect
	(call load-10-mem)
	((m-e) m-2)
	(dispatch-xct-next pdp10-index-and-indirect m-3
	   d-10-index-and-indirect-not-first-time)
       ((m-a) pdp10-index-field m-1)

;Execute the instruction in M-3 with effective address in M-E
;The execution routine finds the accumulator in M-A.
xct-10-insn
	(dispatch-xct-next pdp10-insn-class m-3 d-10-insn-class)
       ((m-a) pdp10-ac-field m-3)

;Dispatch on major classes of pdp-10 instructions.
(locality d-mem)
(start-dispatch 3 0)
d-10-insn-class
	(xct-10-uuo)
	(xct-10-random)
	(xct-10-move)
	(xct-10-jump)
	(xct-10-logical)
	(xct-10-halfword)
	(xct-10-test)
	(xct-10-uuo)
(end-dispatch)
(locality i-mem)

;Do the store for an instruction like ADD
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-both
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-both)
(end-dispatch)
(locality i-mem)

store-10-both
	(call store-10-mem)
	(jump store-10-ac)

;Do the store for an instruction like MOVE
;which is from memory, to memory, immediate or to both.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self
	(p-bit store-10-ac)
	(p-bit store-10-ac)
	(p-bit store-10-mem)
	(p-bit store-10-self)
(end-dispatch)
(locality i-mem)

store-10-self
	(call store-10-mem)
	(popj-equal m-a)
	(jump store-10-ac)

;Arithmetic Jump and Skip Instructions

xct-10-jump
;Dispatch on jump vs skip, whether to increment, etc.
	(dispatch pdp10-jump-subclass m-3 d-10-jump-subclass)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-subclass
	(i-10-cai)
	(i-10-cam)
	(i-10-jump)
	(i-10-skip)
	(i-10-aoj)
	(i-10-aos)
	(i-10-soj)
	(i-10-sos)
(locality i-mem)

;Depending on type of instruction,
;we get our argument from somewhere
;and then supply one of these as I-ARG when we test the condition.
(assign cond-10-jump 0)
(assign cond-10-skip 1)

i-10-cam
	(call load-10-mem-t)
	(call load-10-ac)
	(call sub-10-no-flags)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-cai
	(call load-10-ac)
	((m-2) sub m-2 a-e)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 i-10-cai-1)
	((m-1) sub m-1 (a-constant 1))
i-10-cai-1
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-jump
	(call load-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-skip
	(call load-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aoj
	(call load-10-ac)
	(call inc-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-aos
	(call load-10-mem)
	(call inc-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-soj
	(call load-10-ac)
	(call dec-10)
	(call store-10-ac)
	(dispatch (i-arg cond-10-jump) pdp10-jump-condition m-3 d-10-jump-condition)

i-10-sos
	(call load-10-mem)
	(call dec-10)
	(call store-10-mem)
	(call-not-equal m-a a-zero store-10-ac)
	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)

;Jump or Skip on Sign of Internal Accumulator.

;Do it with an instruction
;	(dispatch (i-arg cond-10-skip) pdp10-jump-condition m-3 d-10-jump-condition)
;The I-ARG should be COND-10-JUMP to jump, COND-10-SKIP to skip.

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-jump-condition
	(next-10-insn)	;Jump never
	(cond-10-less)
	(cond-10-equal)
	(cond-10-le)
	(cond-10-always)
	(cond-10-ge)
	(cond-10-ne)
	(cond-10-grtr)
(end-dispatch)
(locality i-mem)

cond-10-le
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
cond-10-equal
	(jump-not-equal m-1 next-10-insn)
	(jump-not-equal m-2 next-10-insn)
	(jump cond-10-always)

cond-10-grtr
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-ne
	(jump-not-equal m-1 cond-10-always)
	(jump-not-equal m-2 cond-10-always)
	(jump next-10-insn)

cond-10-less
	(jump-if-bit-set pdp10-sign-bit m-1 cond-10-always)
	(jump next-10-insn)

cond-10-ge
	(jump-if-bit-set pdp10-sign-bit m-1 next-10-insn)
cond-10-always
	(dispatch-xct-next read-i-arg d-10-jump-action)
       ((m-b) add m-b (a-constant 1))
;The last instruction does a skip.
;If we are really jumping, it makes no difference.
;If we want to skip, we can go straight to the instruction loop.

(locality d-mem)
(start-dispatch 1 0)
d-10-jump-action
	(jump-10-jump)
	(next-10-insn)
(end-dispatch)
(locality i-mem)

;Halfword Instructions

;Subroutines

;Store M-2 in half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
store-10-ac-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-ac-half)
       (popj-after-next (oa-reg-low) dpb m-a oal-a-dest a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-ac-half
	(store-10-ac-left)
	(store-10-ac-right)
(end-dispatch)

store-10-ac-left
	((a-10-ac-0-left) m-2)

store-10-ac-right
	((a-10-ac-0-right) m-2)

;Load M-2 from half of the simulated AC whose number is in M-A.
;Which half is controlled by the instruction register.
load-10-ac-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-ac-half)
       (popj-after-next (oa-reg-high) dpb m-a oah-a-src a-zero)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-ac-half
	(load-10-ac-left)
	(load-10-ac-right)
(end-dispatch)

load-10-ac-left
	((m-2) a-10-ac-0-left)

load-10-ac-right
	((m-2) a-10-ac-0-right)

;Store M-2 in half of the simulated memory location with address in M-E.
;Which half is controlled by the instruction register.
store-10-mem-half
	(dispatch-xct-next pdp10-halfword-store-right-bit m-3 d-store-10-mem-half)
       ((write-memory-data) m-2)

(locality d-mem)
(start-dispatch 1 0)
d-store-10-mem-half
	(store-10-mem-left)
	(store-10-mem-right)
(end-dispatch)

store-10-mem-left
	((vma-start-write) add m-e a-10-mem-0-left-addr)
	(check-page-write)
	(popj)

store-10-mem-right
	((vma-start-write) add m-e a-10-mem-0-right-addr)
	(check-page-write)
	(popj)

;Load M-2 from half of the simulated memory location whose address is in M-E.
;Which half is controlled by the instruction register.
load-10-mem-half
	(dispatch-xct-next pdp10-halfword-fetch-right-bit m-3 d-load-10-mem-half)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-load-10-mem-half
	(load-10-mem-left)
	(load-10-mem-right)
(end-dispatch)

load-10-mem-left
	((vma-start-read) add m-e a-10-mem-0-left-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

load-10-mem-right
	((vma-start-read) add m-e a-10-mem-0-right-addr)
	(check-page-read)
	(popj (m-2) read-memory-data)

;Load M-2 from half of the immediate arg.
;Which half is controlled by the instruction register.
load-10-immed-half
	(dispatch pdp10-halfword-fetch-right-bit m-3 d-load-10-immed-half)

(locality d-mem)
(start-dispatch 1 0)
d-load-10-immed-half
	(load-10-immed-left)
	(load-10-immed-right)
(end-dispatch)

load-10-immed-left
	(popj (m-2) a-zero)

load-10-immed-right
	(popj (m-2) m-e)

xct-10-halfword
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both-half)
	(dispatch pdp10-other-halfword-action m-3 d-other-10-halfword)
	(jump-if-bit-set pdp10-halfword-store-right-bit m-3 xct-10-halfword-1)
	((m-c) m-1)
	((m-1) m-2)
	((m-2) m-c)
xct-10-halfword-1
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-load-in-out-or-both-half
	(p-bit load-10-mem-half)
	(p-bit load-immed-arg-half)
	(p-bit load-10-ac-half)
	(p-bit load-10-mem-half)
(end-dispatch)
(locality i-mem)

;Clear, set or sign-extend the "other" half,
;which right now is always in M-1.
(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-other-10-halfword
	(xct-10-halfword-preserve-other-half)
	(p-bit other-10-halfword-clear)
	(p-bit other-10-halfword-set)
	(p-bit other-10-halfword-extend)
(end-dispatch)
(locality i-mem)

other-10-halfword-extend
	(jump-if-bit-set pdp10-sign-bit m-2 other-10-halfword-set)
other-10-halfword-clear
	(popj (m-1) a-zero)

other-10-halfword-set
	(popj (m-1) (a-constant 777777))

xct-10-halfword-preserve-other-half
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self-half)
	(jump next-10-insn)

;Do the store for an instruction like HRL
;which only wants to store one halfword
;and can do it in the AC, in memory or in self.
(locality d-mem)
(start-dispatch 3 inhibit-xct-next-bit)
d-10-store-in-out-or-self-halfword
	(p-bit store-10-ac-half)
	(p-bit store-10-ac-half)
	(p-bit store-10-mem-half)
	(p-bit store-10-self-half)
(end-dispatch)
(locality i-mem)

store-10-self-half
	(call store-10-mem-half)
	(popj-equal m-a)
	(jump store-10-ac-half)

;Simple arithmetic subroutines.

sub-10-no-flags
	((m-1) sub m-1 m-t)
	((m-2) sub m-2 m-r)
	(jump-if-bit-clear pdp10-carry-0-bit m-2 sub-10-a)
	((m-1) sub m-1 (a-constant 1))
sub-10-a
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

inc-10
	((m-2) add m-2 (a-constant 1))
	(jump-if-bit-set pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
inc-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

dec-10
	((m-2) sub m-2 (a-constant 1))
	(jump-if-bit-clear pdp10-carry-0-bit m-2 inc-10-a)
	((m-1) add m-1 (a-constant 1))
dec-10-a
;;;??? Needs to compute and save carry 0, carry 1 and overflow flags.
	(popj-after-next
	 (m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)

;AND, etc.

xct-10-logical
	(call load-10-ac)
	(dispatch pdp10-operation-direction m-3 d-10-load-in-out-or-both)
	((m-c) pdp10-logical-operation m-3)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-1) setz m-1 a-t)
	((oa-reg-low) dpb m-c oal-aluf a-zero)
	((m-2) setz m-2 a-r)
	(dispatch pdp10-operation-direction m-3 d-10-store-in-out-or-self)
	(jump next-10-insn)

;TRNN, etc.

xct-10-test
;Fetch the test mask from effective address or memory.
	(dispatch pdp10-test-source-bit m-3 d-10-test-source)
;Swap the test mask's halves if appropriate.
	(jump-if-bit-clear-xct-next pdp10-test-swapped-bit m-3 xct-10-test-1)
       ((m-1) m-t)
	((m-t) m-r)
	((m-r) m-1)
xct-10-test-1
;Fetch the AC to be tested.
	(call load-10-ac)
;Are any masked bits nonzero?
	((m-i) and m-1 a-t)
	((m-j) and m-2 a-r)
	(dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
       ((m-i) ior m-i a-j)
;Maybe store new contents in AC.
	(dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 1 inhibit-xct-next-bit)
d-10-test-source
	(p-bit xct-10-test-immed)
	(p-bit load-10-mem-t)
(end-dispatch)
(locality i-mem)

xct-10-test-immed
	(popj-after-next
	 (m-r) m-e)
	((m-t) a-zero)

;Decide whether to skip, and maybe do so.
;Called with (dispatch-xct-next pdp10-test-condition m-3 d-10-test-condition)
;The thing to test is whether M-I is nonzero.

(locality d-mem)
(start-dispatch 2 0)
d-10-test-condition
	(xct-10-test-2)	;Do not skip.
	(p-bit xct-10-test-skip-if-0)
	(p-bit xct-10-test-skip-always)
	(p-bit xct-10-test-skip-not-0)
(end-dispatch)
(locality i-mem)

xct-10-test-skip-not-0
	(jump-xct-next xct-10-test-skip-always)
	(popj-equal m-i a-zero)
;;;??? Will that work?

xct-10-test-skip-if-0
	(popj-not-equal m-i a-zero)
xct-10-test-skip-always
	(popj (m-b) add m-b (a-constant 1))

;Compute and store the new contents of the accumulator.
;Called by (dispatch pdp10-test-modification m-3 d-10-test-modification)

(locality d-mem)
(start-dispatch 2 inhibit-xct-next-bit)
d-10-test-modification
	(next-10-insn)
	(xct-10-test-set-zero)
	(xct-10-test-complement)
	(xct-10-test-set-one)
(end-dispatch)
(locality i-mem)

xct-10-test-set-zero
	((m-1) andca m-1 a-t)
	((m-2) andca m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-complement
	((m-1) xor m-1 a-t)
	((m-2) xor m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

xct-10-test-set-one
	((m-1) ior m-1 a-t)
	((m-2) ior m-2 a-r)
	(jump-xct-next next-10-insn)
	(call store-10-ac)

;Stack instructions

i-10-push
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

i-10-pop
	(call-xct-next load-10-ac)
       ((c-pdl-buffer-pointer-push) m-e)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) c-pdl-buffer-pointer-pop)
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)


i-10-popj
	(call load-10-ac)
	(call-xct-next load-10-mem-t)
       ((m-e) m-2)
;Set the PC.
	((m-b) add m-r a-10-mem-0-left-addr)
	((m-b) sub (a-constant 1))
;Decrement the halves of the AC.
	((m-1) sub m-1 (a-constant 1))
	((m-2) sub m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	((m-2) truncate-to-halfword m-2)
	(call store-10-ac)
	(jump-not-equal	m-1 (a-constant -1) next-10-insn)
	(jump pdl-10-overflow)

i-10-pushj
	(call load-10-ac)
	(call-xct-next get-10-pc-and-flags-t)
       ((m-1) add m-1 (a-constant 1))
	((m-2) add m-2 (a-constant 1))
	((m-1) truncate-to-halfword m-1)
	(call-xct-next store-10-ac)
       ((m-2) truncate-to-halfword m-2)
	(call-xct-next store-10-mem-t)
       ((m-e) m-2)
	(jump-not-equal m-1 a-zero next-10-insn)
	(jump pdl-10-overflow)

;Byte instructions.

i-10-ibp
	(call inc-10-bp)
	(jump next-10-insn)


;Truncate the PDP-10 quantity in the A register
;to the length specified in M-C.
truncate-10-byte
	(jump-greater-than m-c (a-constant 18.) truncate-10-byte-1)
	(popj-equal-xct-next m-c (a-constant 18.))
       ((m-1) a-zero)
	(jump-equal-xct-next m-c a-zero truncate-10-byte-0-length)
       ((m-c) sub m-c (a-constant 1))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-2) byte-inst m-2 a-zero)

truncate-10-byte-0-length
	(popj (m-2) a-zero)

truncate-10-byte-1
	((m-c) sub m-c (a-constant 19.))
	(popj-after-next
	 (oa-reg-low) dpb m-c oal-bytl-1 a-zero)
	((m-1) byte-inst m-1 a-zero)


;Increment the byte pointer in the PDP-10 memory location
;addressed by M-E.  Store it back in that memory location.
inc-10-bp
	(call load-10-mem)
	((m-t) pdp10-bp-position m-1)
	((m-r) pdp10-bp-size m-1)
	((m-t) sub m-t a-r)
	(call-less-than m-t a-zero inc-10-bp-next-word)
	((m-1) dpb m-t pdp10-bp-position a-1)
	(jump store-10-mem)

inc-10-bp-next-word
	((m-1) add m-1 (a-constant 1))
	(popj-after-next (m-t) (a-constant 36.))
       ((m-t) sub m-t a-r)

i-10-ildb
	(jump-if-bit-set pdp10-fpd-flag a-10-flags i-10-ldb)
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-ldb-0)

i-10-ldb
	(call load-10-mem)
i-10-ldb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Shift it right so desired byte is on the bottom.
	((m-c) pdp10-bp-position m-3)
	(call shift-10-right)
;Depending on whether byte size is more than 18,
;we must truncate M-1, or clear M-1 and truncate M-2.
;If it's exactly 0 or 18, we must clear one or both, but not truncate.
	((m-c) pdp10-bp-size m-3)
	(call truncate-10-byte)
	(jump-xct-next next-10-insn)
       (call store-10-ac)

i-10-idpb
	(jump-if-bit-set pdp10-fpd-flag a-10-flags i-10-dpb)
	(call inc-10-bp)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) ior m-1 a-10-flags)
	(jump i-10-dpb-0)

i-10-dpb
	(call load-10-mem)
i-10-dpb-0
	((m-3) m-1)
	((m-e) m-2)
;Compute effective address of byte pointer,
;preserving M-A over it.
	((c-pdl-buffer-pointer-push) m-a)
	(dispatch-xct-next pdp10-index-and-indirect m-3 d-10-index-and-indirect)
       ((m-a) pdp10-index-field m-3)
	((m-a) c-pdl-buffer-pointer-pop)
;Fetch the word addressed by the byte pointer.
	(call load-10-mem-t)
	((m-1) (a-constant pdp10-fpd-flag))
	((a-10-flags) andcm m-1 a-10-flags)
;Now zero out the byte we want to replace.
 ;Load -1 into the A-register, and shift/truncate it to the byte we want.
	((m-1) a-minus-one)
	((m-2) a-minus-one)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
 ;Now clear that byte in the T register.
	((m-t) andca m-t a-1)
	((m-r) andca m-r a-1)
;Get the byte into A register, truncate, and shift into position.
	(call load-10-ac)
	(call-xct-next shift-10-left)
       ((m-c) pdp10-bp-position m-3)
	(call-xct-next truncate-10-byte)
       ((m-c) pdp10-bp-size m-3)
;Merge it into T register.
	((m-t) ior m-t a-1)
	((m-r) ior m-r a-2)
;Store the result.
	(jump-xct-next next-10-insn)
       (call store-10-mem-t)

;The XCT instruction.
i-10-xct
	(call load-10-mem)
	((m-3) m-1)
	((m-e) m-2)
	(jump eff-addr-comp)

i-10-jrst
;If not JRSTF, just jump.
	(jump-if-bit-clear pdp10-jrstf-bit m-3 jump-10-jump)
;We must reconstruct the flags to restore!
;The result of any indirection is still in M-1,
;but any indexing which followed it was only done for the right half (M-E).
;So we must do it now for the left half.
;Also, if there was no indirection, we must initialize M-1 to zero.
	(jump-if-bit-set pdp10-indirect-bit m-3 i-10-jrstf-1)
	((m-1) a-zero)
i-10-jrstf-1
	((m-a) pdp10-index-field m-3)
	((oa-reg-high) dpb m-a oah-a-src a-zero)
	((m-1) add m-1 a-10-ac-0-left)
	((a-10-flags) mask-field m-1 a-zero)
	(jump jump-10-jump)

i-10-jsr
	(call get-10-pc-and-flags-t)
	(call store-10-mem-t)
	(jump-xct-next jump-10-jump)
       ((m-e) add m-e (a-constant 1))

i-10-jsp
	(call get-10-pc-and-flags-t)
	(jump-xct-next jump-10-jump)
       (call store-10-ac-t)

i-10-jsa
	(call load-10-ac)
	(call store-10-mem)
	(call-xct-next get-10-pc)
       ((m-1) m-e)
	(call store-10-ac)
	(jump-xct-next jump-10-jump)
	((m-e) add m-e (a-constant 1))

i-10-jra
	((m-t) m-e)
	(call load-10-ac)
	((m-e) m-1)
	(call load-10-mem)
	(call store-10-ac)
	((m-e) m-t)
	(jump jump-10-jump)	
	
;Shift instructions.
i-10-lsh
	(call load-10-ac)
	(jump-greater-than-or-equal m-e a-zero i-10-lsh-left)
	((m-c) sub m-zero a-e)
	(call shift-10-right)
       ((m-c) pdp10-shift-count m-c)
	(call store-10-ac)
	(jump next-10-insn)

i-10-lsh-left
	(call shift-10-left)
       ((m-c) pdp10-shift-count m-e)
	(call store-10-ac)
	(jump next-10-insn)

i-10-ash
	(call load-10-ac)
	(jump-greater-than-or-equal m-e a-zero i-10-lsh-left)
	((m-c) sub m-zero a-e)
	(call arith-shift-10-right)
       ((m-c) pdp10-shift-count m-c)
	(call store-10-ac)
	(jump next-10-insn)

;;;??? No point in writing the rest until I can write
;SHIFT-10-LEFT, etc.