Source Code
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These source-code files are part of a reconstructed copy of Comanche 45, the
second release, though not the final mission release, of the Apollo 10
Command Module (CM) Apollo Guidance Computer (AGC) software. Comanche 45 was
preceded by Comanche 44 and followed by Comanche 45/2 (the flown release). The reconstruction
is believed to be exactly accurate, but in the absence of an actual Apollo-era
listing of Comanche 45, some explanation of the reconstruction process is needed
to insure confidence in that accuracy.
The starting point was the source code of Comanche 44 (itself previously accurately
reconstructed). Comanche 44 source code was then modified
by incorporating changes known from contemporary documentation to have been
made between revisions 44 and 45. The now-reconstructed Comanche 45 source code was
verified by assembling it and checking that the assembled code had
the expected known-correct memory-bank checksums.
Note that page numbers in the reconstructed code tend to match those in the Comanche 55, the
most-similar revision of Comanche for which we have access to an actual non-reconstructed hardcopy;
the source code would likely have different page numbers in a contemporary
Comanche 45 listing.
Annotations that were not present in the contemporary source code have been added to the reconstructed
code to justify each change relative to Comanche 44. Here's a guide to the Apollo documentation referenced
in those annotations:
There is also
a detailed commentary about the reconstruction process.
Comments expected to have been present in the original source code are prefixed with a single '#' symbol,
whereas comments added later are prefixed by "##" or "###". Report any errors
noted by creating an
issue report at the Virtual AGC
Project's GitHub repository.
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047884,000002: ## Copyright: Public domain.
047885,000003: ## Filename: INTER-BANK_COMMUNICATION.agc
047886,000004: ## Purpose: A section of Comanche revision 045.
047887,000005: ## It is part of the reconstructed source code for the
047888,000006: ## second release of the flight software for the Command
047889,000007: ## Module's (CM) Apollo Guidance Computer (AGC) for Apollo 10.
047890,000008: ## The code has been recreated from a copy of Comanche 055. It
047891,000009: ## has been adapted such that the resulting bugger words
047892,000010: ## exactly match those specified for Comanche 45 in NASA drawing
047893,000011: ## 2021153D, which gives relatively high confidence that the
047894,000012: ## reconstruction is correct.
047895,000013: ## Assembler: yaYUL
047896,000014: ## Contact: Ron Burkey <info@sandroid.org>.
047897,000015: ## Website: www.ibiblio.org/apollo/index.html
047898,000016: ## Mod history: 2020-12-06 MAS Created from Comanche 44.
047899,000017:
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Page 1103
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047901,000019: # THE FOLLOWING ROUTINE CAN BE USED TO CALL A SUBROUTINE IN ANOTHER BANK. IN THE BANKCALL VERSION, THE
047902,000020: # CADR OF THE SUBROUTINE IMMEDIATELY FOLLOWS THE TC BANKCALL INSTRUCTION, WITH C(A) AND C(L) PRESERVED.
047903,000021:
047904,000022: 4662 BLOCK 02
047905,000023: 4662 COUNT 02/BANK
047906,000024:
047907,000025: 4662 52134 BANKCALL DXCH BUF2 # SAVE INCOMING A,L.
047908,000026: 4663 50002 INDEX Q # PICK UP CADR.
047909,000027: 4664 30000 CA 0
047910,000028: 4665 24002 INCR Q # SO WE RETURN TO THE LOC. AFTER THE CADR.
047911,000029:
047912,000030: # SWCALL IS IDENTICAL TO BANKCALL, EXCEPT THAT THE CADR ARRIVES IN A.
047913,000031:
047914,000032: 4666 54001 SWCALL TS L
047915,000033: 4667 22004 LXCH FBANK # SWITCH BANKS, SAVING RETURN.
047916,000034: 4670 75054 MASK LOW10 # GET SUB-ADDRESS OF CADR.
047917,000035: 4671 56002 XCH Q # A,L NOW CONTAINS DP RETURN.
047918,000036: 4672 52134 DXCH BUF2 # RESTORING INPUTS IF THIS IS A BANKCALL.
047919,000037: 4673 50002 INDEX Q
047920,000038: 4674 02000 TC 10000 # SETTING Q TO SWRETURN.
047921,000039:
047922,000040: 4675 56134 SWRETURN XCH BUF2 +1 # COMES HERE TO RETURN TO CALLER. C(A,L)
047923,000041: 4676 56004 XCH FBANK # ARE PRESERVED FOR RETURN.
047924,000042: 4677 56134 XCH BUF2 +1
047925,000043: 4700 00133 TC BUF2
047926,000044:
047927,000045: # THE FOLLOWING ROUTINE CAN BE USED AS A UNILATERAL JUMP WITH C(A,L) PRESERVED AND THE CADR IMMEDIATELY
047928,000046: # FOLLOWING THE TC POSTJUMP INSTRUCTION.
047929,000047:
047930,000048: 4701 56002 POSTJUMP XCH Q # SAVE INCOMING C(A).
047931,000049: 4702 50000 INDEX A # GET CADR.
047932,000050: 4703 30000 CA 0
047933,000051:
047934,000052: # BANKJUMP IS THE SAME AS POSTJUMP, EXCEPT THAT THE CADR ARRIVES IN A.
047935,000053:
047936,000054: 4704 54004 BANKJUMP TS FBANK
047937,000055: 4705 75054 MASK LOW10
047938,000056: 4706 56002 XCH Q # RESTORING INPUT C(A) IF THIS WAS A
047939,000057: 4707 50002 Q+10000 INDEX Q # POSTJUMP.
047940,000058: 4710 12000 PRIO12 TCF 10000 # PRIO12 = TCF 10000 = 12000
047941,000059:
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Page 1104
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047943,000061: # THE FOLLOWING ROUTINE GETS THE RETURN CADR SAVED BY SWCALL OR BANKCALL AND LEAVES IT IN A.
047944,000062:
047945,000063: 4711 35054 MAKECADR CAF LOW10
047946,000064: 4712 70133 MASK BUF2
047947,000065: 4713 60134 AD BUF2 +1
047948,000066: 4714 00002 TC Q
047949,000067:
047950,000068: 4715 54135 SUPDACAL TS MPTEMP
047951,000069: 4716 56004 XCH FBANK # SET FBANK FOR DATA.
047952,000070: 4717 00006 EXTEND
047953,000071: 4720 04007 ROR SUPERBNK # SAVE FBANK IN BITS 15-11, AND
047954,000072: 4721 56135 XCH MPTEMP # SUPERBANK IN BITS 7-5.
047955,000073: 4722 75054 MASK LOW10
047956,000074: 4723 56001 XCH L # SAVE REL. ADR. IN BANK, FETCH SUPERBITS.
047957,000075: 4724 00004 INHINT # BECAUSE RUPT DOES NOT SAVE SUPERBANK.
047958,000076: 4725 00006 EXTEND
047959,000077: 4726 01007 WRITE SUPERBNK # SET SUPERBANK FOR DATA.
047960,000078: 4727 50001 INDEX L
047961,000079: 4730 32000 CA 10000 # PINBALL (FIX MEM DISP) PREVENTS DCA HERE
047962,000080: 4731 56135 XCH MPTEMP # SAVE 1ST WD, FETCH OLD FBANK AND SBANK.
047963,000081: 4732 00006 EXTEND
047964,000082: 4733 01007 WRITE SUPERBNK # RESTORE SUPERBANK.
047965,000083: 4734 00003 RELINT
047966,000084: 4735 54004 TS FBANK # RESTORE FBANK.
047967,000085: 4736 30135 CA MPTEMP # RECOVER FIRST WORD OF DATA.
047968,000086: 4737 00002 RETURN # 24 WDS. DATACALL 516 MU, SUPDACAL 432 MU
047969,000087:
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Page 1105
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047971,000089: # THE FOLLOWING ROUTINES ARE IDENTICAL TO BANKCALL AND SWCALL EXCEPT THAT THEY ARE USED IN INTERRUPT.
047972,000090:
047973,000091: 4740 52073 IBNKCALL DXCH RUPTREG3 # USES RUPTREG3,4 FOR DP RETURN ADDRESS.
047974,000092: 4741 50002 INDEX Q
047975,000093: 4742 30000 CAF 0
047976,000094: 4743 24002 INCR Q
047977,000095:
047978,000096: 4744 54001 ISWCALL TS L
047979,000097: 4745 22004 LXCH FBANK
047980,000098: 4746 75054 MASK LOW10
047981,000099: 4747 56002 XCH Q
047982,000100: 4750 52073 DXCH RUPTREG3
047983,000101: 4751 50002 INDEX Q
047984,000102: 4752 02000 TC 10000
047985,000103:
047986,000104: 4753 56073 ISWRETRN XCH RUPTREG4
047987,000105: 4754 56004 XCH FBANK
047988,000106: 4755 56073 XCH RUPTREG4
047989,000107: 4756 00072 TC RUPTREG3
047990,000108:
047991,000109: # 2. USPRCADR ACCESSES INTERPRETIVE CODING IN OTHER THAN THE USER'S FBANK. THE CALLING SEQUENCE IS AS FOLLOWS:
047992,000110: # L TC USPRCADR
047993,000111: # L+1 CADR INTPRETX INTPRETX IS THE INTERPRETIVE CODING
047994,000112: # RETURN IS TO L+2
047995,000113:
047996,000114: 4757 54164 USPRCADR TS LOC # SAVE A
047997,000115: 4760 35010 CA BIT8
047998,000116: 4761 54023 TS EDOP # EXIT INSTRUCTION TO EDOP
047999,000117: 4762 30006 CA BBANK
048000,000118: 4763 54165 TS BANKSET # USER'S BBANK TO BANKSET
048001,000119: 4764 50002 INDEX Q
048002,000120: 4765 30000 CA 0
048003,000121: 4766 54004 TS FBANK # INTERPRETIVE BANK TO FBANK
048004,000122: 4767 75054 MASK LOW10 # YIELDS INTERPRETIVE RELATIVE ADDRESS
048005,000123: 4770 56002 XCH Q # INTERPRETIVE ADDRESS TO Q, FETCHING L+1
048006,000124: 4771 56164 XCH LOC # L+1 TO LOC, RETRIEVING ORIGINAL A
048007,000125: 4772 14707 TCF Q+10000
048008,000126:
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Page 1106
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048010,000128: # THERE ARE FOUR POSSIBLE SETTINGS FOR CHANNEL 07. (CHANNEL 07 CONTAINS THE SUPERBANK SETTING.)
048011,000129:
048012,000130: # PSEUDO-FIXED OCTAL PSEUDO
048013,000131: # SUPERBANK SETTING S-REG. VALUE BANK NUMBERS ADDRESSES
048014,000132: # ---------- ------- ------------ ------------ ------------
048015,000133: # SUPERBANK 3 0XX 2000 - 3777 30 - 37 70000 - 107777 (WHERE XX CAN BE ANYTHING AND
048016,000134: # WILL USUALLY BE SEEN AS 11)
048017,000135: # SUPERBANK 4 100 2000 - 3777 40 - 47 110000 - 127777 (AS FAR AS IT CAN BE SEEN,
048018,000136: # ONLY BANKS 40-43 WILL EVER BE
048019,000137: # AND ARE PRESENTLY AVAILABLE)
048020,000138: # SUPERBANK 5 101 2000 - 3777 50 - 57 130000 - 147777 (PRESENTLY NOT AVAILABLE TO
048021,000139: # THE USER)
048022,000140: # SUPERBANK 6 110 2000 - 3777 60 - 67 150000 - 167777 (PRESENTLY NOT AVAILABLE TO
048023,000141: # THE USER)
048024,000142: # *** THIS ROUTINE MAY BE CALLED BY ANY PROGRAM LOCATED IN BANKS 00 - 27. I.E., NO PROGRAM LIVING IN ANY
048025,000143: # SUPERBANK SHOULD USE SUPERSW. ***
048026,000144:
048027,000145: # SUPERSW MAY BE CALLED IN THIS FASHION:
048028,000146: # CAF ABBCON WHERE -- ABBCON BBCON SOMETHIN --
048029,000147: # TCR SUPERSW (THE SUPERBNK BITS ARE IN THE BBCON)
048030,000148: # ... ...
048031,000149: # . .
048032,000150: # . .
048033,000151: # OR IN THIS FASHION:
048034,000152: # CAF SUPERSET WHERE SUPERSET IS ONE OF THE FOUR AVAILABLE
048035,000153: # TCR SUPERSW SUPERBANK BIT CONSTANTS:
048036,000154: # ... ... SUPER011 OCTAL 60
048037,000155: # . . SUPER100 OCTAL 100
048038,000156: # . . SUPER101 OCTAL 120
048039,000157: # SUPER110 OCTAL 140
048040,000158:
048041,000159: 4773 00006 SUPERSW EXTEND
048042,000160: 4774 01007 WRITE SUPERBNK # WRITE BITS 7-6-5 OF THE ACCUMULATOR INTO
048043,000161: # CHANNEL 07
048044,000162: 4775 00002 TC Q # TC TO INSTRUCTION FOLLOWING
048045,000163: # TC SUPERSW
048046,000164:
048047,000165:
048048,000166:
End of include-file INTER-BANK_COMMUNICATION.agc. Parent file is MAIN.agc