Source Code
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These source-code files are part of a reconstructed copy of Comanche 51, the
initial release (though not the final mission release) of the Apollo 11
Command Module (CM) Apollo Guidance Computer (AGC) software. The flown, final
release was Comanche 55. The reconstruction is believed to be exactly accurate,
but in the absence of an actual Apollo-era listing of Comanche 51, some
explanation of the reconstruction process is needed to insure confidence in
that accuracy.
The starting point was the source code of Comanche 55, whose original source code
is available. Comanche 55 source code was then modified by undoing changes known
to have been made between revisions 51 and 55. The most-significant steps involved
reverting changes related to the R-2 lunar potential model, the details of which
were known from the previous, separate, independent reconstruction of the Apollo 10
Lunar Module software Luminary 69/2. The now-reconstructed
Comanche 51 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 match those on the Comanche 55 or Luminary 69 printouts, although
the source code would likely have different page numbers in a contemporary Comanche 51 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 55. Here's a guide
to some of the Apollo documentation relevant to those annotations:
Among documentation not actually referenced in the annotations, there is
a short writeup about the reconstruction process in our software repository
that may be helpful in understanding it from a different perspective. There's also
a handy table
that lists what the number of memory-words should be for each routine in Comanche 51,
which could make a nice double-check; however, we've not performed that double-check ourselves.
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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063128,000002: ## Copyright: Public domain.
063129,000003: ## Filename: SERVICE_ROUTINES.agc
063130,000004: ## Purpose: A section of Comanche revision 051.
063131,000005: ## It is part of the reconstructed source code for the
063132,000006: ## original release of the flight software for the Command
063133,000007: ## Module's (CM) Apollo Guidance Computer (AGC) for Apollo 11.
063134,000008: ## The code has been recreated from a copy of Comanche 055. It
063135,000009: ## has been adapted such that the resulting bugger words
063136,000010: ## exactly match those specified for Comanche 51 in NASA drawing
063137,000011: ## 2021153D, which gives relatively high confidence that the
063138,000012: ## reconstruction is correct.
063139,000013: ## Reference: pp. 1485-1492
063140,000014: ## Assembler: yaYUL
063141,000015: ## Contact: Ron Burkey <info@sandroid.org>.
063142,000016: ## Website: www.ibiblio.org/apollo/index.html
063143,000017: ## Mod history: 2019-07-30 MAS Created from Comanche 55.
063144,000018:
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Page 1485
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063146,000020: 7722 BLOCK 3
063147,000021: 6000 SETLOC FFTAG6
063148,000022: 6000 BANK
063149,000023: 7722 COUNT 03/FLAG
063150,000024:
063151,000025: 7722 54001 UPENT2 TS L # WHICH FLAGWORD IS IT
063152,000026: 7723 75023 MASK OCT7
063153,000027: 7724 56001 XCH L # SAVE IN L FOR INDEXING
063154,000028:
063155,000029: 7725 75731 MASK OCT77770 # OBTAIN THE BIT INFORMATION
063156,000030: 7726 00004 INHINT # PREVENT INTERUPTS
063157,000031: 7727 54061 TS ITEMP1 # STORE THE BIT INFORMATION TEMPORARIALY
063158,000032:
063159,000033: 7730 50001 NDX L
063160,000034: 7731 40074 CS FLAGWRD0
063161,000035: 7732 70061 MASK ITEMP1
063162,000036: 7733 50001 NDX L
063163,000037: 7734 26074 ADS FLAGWRD0
063164,000038: 7735 00003 RELINT # RELEASE INTERUPT INHIBIT
063165,000039:
063166,000040: 7736 24002 INCR Q # OBTAIN THE CORRECT RETURN ADDRESS
063167,000041: 7737 00002 TC Q # RETURN
063168,000042:
063169,000043: 7740 54001 DOWNENT2 TS L # WHICH FLAGWORD IS IT
063170,000044: 7741 75023 MASK OCT7
063171,000045: 7742 56001 XCH L # SAVE IN L FOR INDEXING
063172,000046:
063173,000047: 7743 75731 MASK OCT77770 # OBTAIN THE BIT INFORMATION
063174,000048: 7744 40000 COM # START TO PROCESS THE INFORMATION
063175,000049:
063176,000050: 7745 00004 INHINT # PREVENT INTERUPTS
063177,000051: 7746 50001 NDX L
063178,000052: 7747 70074 MASK FLAGWRD0
063179,000053: 7750 50001 NDX L
063180,000054: 7751 54074 TS FLAGWRD0
063181,000055: 7752 00003 RELINT # RELEASE INTERUPT INHIBIT
063182,000056:
063183,000057: 7753 24002 INCR Q # OBTAIN THE CORRECT RETURN ADDRESS
063184,000058: 7754 00002 TC Q # RETURN
063185,000059:
063186,000060: 7755 5023 OCT7 EQUALS SEVEN
063187,000061: 10,3766 BANK 10
063188,000062:
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Page 1486
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063190,000064: # UPFLAG AND DOWNFLAG ARE ENTIRELY GENERAL FLAG SETTING AND CLEARING SUBROUTINES. USING THEM, WHETHER OR
063191,000065: # NOT IN INTERRUPT, ONE MAY SET OR CLEAR ANY SINGLE, NAMED BIT IN ANY ERASABLE REGISTER, SUBJECT OF COURSE TO
063192,000066: # EBANK SETTING. A "NAMED" BIT, AS THE WORD IS USED HERE, IS ANY BIT WITH A NAME FORMALLY ASSIGNED BY THE YUL
063193,000067: # ASSEMBLER.
063194,000068:
063195,000069: # AT PRESENT THE ONLY NAMED BITS ARE THOSE IN THE FLAGWORDS. ASSEMBLER CHANGES WILL MAKE IT POSSIBLE TO
063196,000070: # NAME ANY BIT IN ERASABLE MEMORY.
063197,000071:
063198,000072: # CALLING SEQUENCES ARE AS FOLLOWS:-
063199,000073: # TC UPFLAG TC DOWNFLAG
063200,000074: # ADRES NAME OF FLAG ADRES NAME OF FLAG
063201,000075:
063202,000076: # RETURN IS TO THE LOCATION FOLLOWING THE "ADRES" ABOUT .58 MS AFTER THE "TC".
063203,000077: # UPON RETURN A CONTAINS THE CURRENT FLAGWRD SETTING.
063204,000078:
063205,000079: 5546 BLOCK 02
063206,000080: 4000 SETLOC FFTAG1
063207,000081: 4000 BANK
063208,000082: 5546 COUNT* $$/FLAG
063209,000083:
063210,000084: 5546 30002 UPFLAG CA Q
063211,000085: 5547 05564 TC DEBIT
063212,000086: 5550 40000 COM # +(15 - BIT)
063213,000087: 5551 00006 EXTEND
063214,000088: 5552 04001 ROR LCHAN # SET BIT
063215,000089: 5553 50061 COMFLAG INDEX ITEMP1
063216,000090: 5554 54074 TS FLAGWRD0
063217,000091: 5555 22063 LXCH ITEMP3
063218,000092: 5556 00003 RELINT
063219,000093: 5557 00001 TC L
063220,000094:
063221,000095: 5560 30002 DOWNFLAG CA Q
063222,000096: 5561 05564 TC DEBIT
063223,000097: 5562 70001 MASK L # RESET BIT
063224,000098: 5563 15553 TCF COMFLAG
063225,000099:
063226,000100: 5564 65017 DEBIT AD ONE # GET DE BITS
063227,000101: 5565 00004 INHINT
063228,000102: 5566 54063 TS ITEMP3
063229,000103: 5567 35026 CA LOW4 # DEC15
063230,000104: 5570 54061 TS ITEMP1
063231,000105: 5571 50063 INDEX ITEMP3
063232,000106: 5572 27777 CA 0 -1 # ADRES
063233,000107: 5573 54001 TS L
063234,000108: 5574 35021 CA ZERO
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Page 1487
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063236,000110: 5575 00006 EXTEND
063237,000111: 5576 10061 DV ITEMP1 # A = FLAGWRD, L = (15 - BIT)
063238,000112: 5577 52062 DXCH ITEMP1
063239,000113: 5600 50061 INDEX ITEMP1
063240,000114: 5601 30074 CA FLAGWRD0
063241,000115: 5602 54001 TS L # CURRENT STATE
063242,000116: 5603 50062 INDEX ITEMP2
063243,000117: 5604 45001 CS BIT15 # -(15 - BIT)
063244,000118: 5605 00002 TC Q
063245,000119:
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Page 1488
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063247,000121: # DELAYJOB- A GENERAL ROUTINE TO DELAY A JOB A SPECIFIC AMOUNT OF TIME BEFORE PICKING UP AGAIN.
063248,000122:
063249,000123: # ENTRANCE REQUIREMENTS...
063250,000124: # CAF DT DELAY JOB FOR DT CENTISECS
063251,000125: # TC BANKCALL
063252,000126: # CADR DELAYJOB
063253,000127:
063254,000128: 06,3770 BANK 06
063255,000129: 00,2000 SETLOC DLAYJOB
063256,000130: 00,2000 BANK
063257,000131:
063258,000132: # THIS MUST REMAIN IN BANK 0 *****************************************
063259,000133:
063260,000134: 00,3732 COUNT 00/DELAY
063261,000135:
063262,000136: 00,3732 00004 DELAYJOB INHINT
063263,000137: 00,3733 54002 TS Q # STORE DELAY DT IN Q FOR DLY -1 IN
063264,000138: 00,3734 36214 CAF DELAYNUM # WAITLIST
063265,000139: 00,3735 54070 DELLOOP TS RUPTREG1
063266,000140: 00,3736 50000 INDEX A
063267,000141: 00,3737 31141 CA DELAYLOC # IS THIS DELAYLOC AVAILABLE
063268,000142: 00,3740 00006 EXTEND
063269,000143: 00,3741 13746 BZF OK2DELAY # YES
063270,000144:
063271,000145: 00,3742 10070 CCS RUPTREG1 # NO, TRY NEXT DELAYLOC
063272,000146: 00,3743 13735 TCF DELLOOP
063273,000147:
063274,000148: 00,3744 07755 TC BAILOUT # NO AVAILABLE LOCS AVAILABLE.
063275,000149: 00,3745 01104 OCT 1104
063276,000150:
063277,000151: 00,3746 33766 OK2DELAY CA TCSLEEP # SET WAITLIST IMMEDIATE RETURN
063278,000152: 00,3747 54061 TS WAITEXIT
063279,000153:
063280,000154: 00,3750 30004 CA FBANK
063281,000155: 00,3751 60070 AD RUPTREG1 # STORE BBANK FOR TASK CALL
063282,000156: 00,3752 54001 TS L
063283,000157:
063284,000158: 00,3753 33767 CAF WAKECAD # STORE CADR FOR TASK CALL
063285,000159: 00,3754 15255 TCF DLY2 -1 # DLY IS IN WAITLIST ROUTINE
063286,000160:
063287,000161: 00,3755 04711 TCGETCAD TC MAKECADR # GET CALLERS FCADR
063288,000162:
063289,000163: 00,3756 50070 INDEX RUPTREG1
063290,000164: 00,3757 55141 TS DELAYLOC # SAVE DELAY CADRS
063291,000165:
063292,000166: 00,3760 05175 TC JOBSLEEP
063293,000167:
063294,000168: 00,3761 35021 WAKER CAF ZERO
063295,000169: 00,3762 50006 INDEX BBANK
063296,000170: 00,3763 57141 XCH DELAYLOC # MAKE DELAYLOC AVAILABLE
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Page 1489
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063298,000172: 00,3764 05201 TC JOBWAKE
063299,000173:
063300,000174: 00,3765 05324 TC TASKOVER
063301,000175:
063302,000176: 00,3766 03753 TCSLEEP GENADR TCGETCAD -2
063303,000177: 00,3767 03761 WAKECAD GENADR WAKER
063304,000178:
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Page 1490
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063306,000180: # GENTRAN, A BLOCK TRANSFER ROUTINE.
063307,000181: # WRITTEN BY D. EYLES
063308,000182: # MOD 1 BY KERNAN UTILITYM REV 17 11/18/67
063309,000183: # MOD 2 BY SCHULENBERG (REMOVE RELINT) SKIPPER REV 4 2/28/68
063310,000184:
063311,000185: # THIS ROUTINE IS USEFULL FOR TRANSFERING N CONSECUTIVE ERASABLE OR FIXED QUANTITIES TO SOME OTHER N
063312,000186: # CONSECUTIVE ERASABLE LOCATIONS. IF BOTH BLOCKS OF DATA ARE IN SWITCHABLE EBANKS, THEY MUST BE IN THE SAME ONE.
063313,000187:
063314,000188: # GENTRAN IS CALLABLE IN A JOB AS WELL AS A RUPT. THE CALLING SEQUENCE IS:
063315,000189: # I CA N-1 # OF QUANTITIES MINUS ONE.
063316,000190: # I +1 TC GENTRAN IN FIXED-FIXED.
063317,000191: # I +2 ADRES L STARTING ADRES OF DATA TO BE MOVED.
063318,000192: # I +3 ADRES M STARTING ADRES OF DUPLICATION BLOCK.
063319,000193: # I +4 RETURNS HERE.
063320,000194:
063321,000195: # GENTRAN TAKES 25 MCT'S (300 MICROSECONDS) PER ITEM + 5 MCT'S (60 MICS) FOR ENTERING AND EXITING.
063322,000196: # A, L AND ITEMP1 ARE NOT PRESERVED.
063323,000197:
063324,000198: 5606 BLOCK 02
063325,000199: 4000 SETLOC FFTAG4
063326,000200: 4000 BANK
063327,000201:
063328,000202: 5606 0061 EBANK= ITEMP1
063329,000203:
063330,000204: 5606 COUNT* $$/TRAN
063331,000205:
063332,000206: 5606 00004 GENTRAN INHINT
063333,000207: 5607 54061 TS ITEMP1 # SAVE N-1.
063334,000208: 5610 50002 INDEX Q # C(Q) = ADRES L.
063335,000209: 5611 60000 AD 0 # ADRES (L + N - 1).
063336,000210: 5612 50000 INDEX A
063337,000211: 5613 30000 CA 0 # C(ABOVE).
063338,000212: 5614 54001 TS L # SAVE DATA.
063339,000213: 5615 30061 CA ITEMP1
063340,000214: 5616 50002 INDEX Q
063341,000215: 5617 60001 AD 1 # ADRES (M + N - 1).
063342,000216: 5620 50000 INDEX A
063343,000217: 5621 22000 LXCH 0 # STUFF IT.
063344,000218: 5622 10061 CCS ITEMP1 # LOOP UNTIL N-1 = 0.
063345,000219: 5623 15607 TCF GENTRAN +1
063346,000220: 5624 16710 TCF Q+2 # RETURN TO CALLER.
063347,000221:
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Page 1491
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063349,000223: # B5OFF ZERO BIT 5 OF EXTVBACT, WHICH IS SET BY TESTXACT.
063350,000224: # MAY BE USED AS NEEDED BY ANY EXTENDED VERB WHICH HAS DONE TESTXACT
063351,000225:
063352,000226: 5625 COUNT* $$/EXTVB
063353,000227:
063354,000228: 5625 45013 B5OFF CS BIT5
063355,000229: 5626 71044 MASK EXTVBACT
063356,000230: 5627 55044 TS EXTVBACT
063357,000231: 5630 05217 TC ENDOFJOB
063358,000232:
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Page 1492
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063360,000234: # SUBROUTINES TO TURN OFF AND TURN ON TRACKER FAIL LIGHT.
063361,000235:
063362,000236: 5631 00004 TRFAILOF INHINT
063363,000237: 5632 47704 CS OCT40200 # TURN OFF TRACKER LIGHT
063364,000238: 5633 71036 MASK DSPTAB +11D
063365,000239: 5634 65001 AD BIT15
063366,000240: 5635 55036 TS DSPTAB +11D
063367,000241: 5636 41331 CS OPTMODES # TO INSURE THAT OCDU FAIL WILL GO ON
063368,000242: 5637 75011 MASK BIT7 # AGAIN IF IT WAS ON IN ADDITION TO
063369,000243: 5640 27331 ADS OPTMODES # TRACKER FAIL.
063370,000244:
063371,000245: 5641 00003 REQ RELINT
063372,000246: 5642 00002 TC Q
063373,000247:
063374,000248: 5643 00004 TRFAILON INHINT
063375,000249: 5644 41036 CS DSPTAB +11D # TURN ON
063376,000250: 5645 77704 MASK OCT40200
063377,000251: 5646 27036 ADS DSPTAB +11D
063378,000252: 5647 15641 TCF REQ
063379,000253:
063380,000254:
063381,000255:
063382,000256:
End of include-file SERVICE_ROUTINES.agc. Parent file is MAIN.agc