Source Code
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These source-code files are part of a reconstructed copy of Luminary 69/2,
the flown, final release of the Apollo 10 Lunar Module (LM) Apollo Guidance Computer (AGC) software.
The reconstruction is based on the source code of Luminary 69 — i.e., the
initial, unflown version, "revision 0" — of which
a contemporary listing was available. The code was then updated by incorporating the
differences between Luminary 69 and Luminary 69/2, known from other contemporary
documentation. The only such difference is the implementation in
Luminary 69/2 of the "R-2 Lunar Potential Model", the source code for which was taken
from program Luminary 99/1 (Apollo 11 LM), of which a contemporary listing was also available.
Finally, the now-reconstructed Luminary 69/2 was then validated by assembling it to
executable form and verifying that its memory banks had the correct checksums,
known from still other contemporary documentation.
Note that page numbers in the reconstructed code match those in the original Luminary 69
program listing, or in the ORBITAL INTEGRATION log section, in Luminary 99/1. Page numbers
would certainly differ somewhat in a contemporary Luminary 69/2 listing.
Moreover, annotations that were not present in the contemporary source code have been added
to the reconstructed code to justify each change in Luminary 69/2 relative to
Luminary 69. Here's a guide to the Apollo documentation referenced in those annotations:
Comments from 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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060369,000002: ## Copyright: Public domain.
060370,000003: ## Filename: T6-RUPT_PROGRAMS.agc
060371,000004: ## Purpose: A section of LUM69 revision 2.
060372,000005: ## It is part of the reconstructed source code for the flown
060373,000006: ## version of the flight software for the Lunar Module's (LM)
060374,000007: ## Apollo Guidance Computer (AGC) for Apollo 10. The code has
060375,000008: ## been recreated from a copy of Luminary revsion 069, using
060376,000009: ## changes present in Luminary 099 which were described in
060377,000010: ## Luminary memos 75 and 78. The code has been adapted such
060378,000011: ## that the resulting bugger words exactly match those specified
060379,000012: ## for LUM69 revision 2 in NASA drawing 2021152B, which gives
060380,000013: ## relatively high confidence that the reconstruction is correct.
060381,000014: ## Reference: pp. 1398-1400
060382,000015: ## Assembler: yaYUL
060383,000016: ## Contact: Ron Burkey <info@sandroid.org>.
060384,000017: ## Website: www.ibiblio.org/apollo/index.html
060385,000018: ## Mod history: 2019-07-27 MAS Created from Luminary 69.
060386,000019:
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Page 1398
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060388,000021: # PROGRAM NAMES: (1) T6JOBCHK MOD. NO. 5 OCTOBER 2, 1967
060389,000022: # (2) DOT6RUPT
060390,000023: # MODIFICATION BY: LOWELL G HULL (A.C.ELECTRONICS)
060391,000024:
060392,000025: # THESE PROGRAMS ENABLE THE LM DAP TO CONTROL THE THRUST TIMES OF THE REACTION CONTROL SYSTEM JETS BY USING TIME6.
060393,000026: # SINCE THE LM DAP MAINTAINS EXCLUSIVE CONTROL OVER TIME6 AND ITS INTERRUPTS, THE FOLLOWING CONVENTIONS HAVE BEEN
060394,000027: # ESTABLISHED AND MUST NOT BE TAMPERED WITH:
060395,000028: # 1. NO NUMBER IS EVER PLACED INTO TIME6 EXCEPT BY LM DAP.
060396,000029: # 2. NO PROGRAM OTHER THAN LM DAP ENABLES THE TIME6 COUNTER.
060397,000030: # 3. TO USE TIME6, THE FOLLOWING SEQUENCE IS ALWAYS EMPLOYED:
060398,000031: # A. A POSITIVE (NON-ZERO) NUMBER IS STORED IN TIME6.
060399,000032: # B. THE TIME6 CLOCK IS ENABLED.
060400,000033: # C. TIME6 IS INTERROGATED AND IS:
060401,000034: # I. NEVER FOUND NEGATIVE (NON-ZERO) OR +0.
060402,000035: # II. SOMETIMES FOUND POSITIVE (BETWEEN 1 AND 240D) INDICATING THAT IT IS ACTIVE.
060403,000036: # III. SOMETIMES FOUND POSMAX INDICATING THAT IT IS INACTIVE AND NOT ENABLED.
060404,000037: # IV. SOMETIMES FOUND NEGATIVE ZERO INDICATING THAT:
060405,000038: # A. A T6RUPT IS ABOUT TO OCCUR AT THE NEXT DINC, OR
060406,000039: # B. A T6RUPT IS WAITING IN THE PRIORITY CHAIN, OR
060407,000040: # C. A T6RUPT IS IN PROCESS NOW.
060408,000041: # 4) ALL PROGRAMS WHICH OPERATE IN EITHER INTERRUPT MODE OR WITH INTERRUPT INHIBITED MUST CALL T6JOBCHK
060409,000042: # EVERY 5 MILLISECONDS TO PROCESS A POSSIBLE WAITING T6RUPT BEFORE IT CAN BE HONORED BY THE HARDWARE.
060410,000043: # (5. PROGRAM JTLST, IN Q,R-AXES, HANDLES THE INPUT LIST.)
060411,000044:
060412,000045: # T6JOBCHK CALLING SEQUENCE:
060413,000046: # L TC T6JOBCHK
060414,000047: # L+1 (RETURN)
060415,000048:
060416,000049: # DOT6RUPT CALLING SEQUENCE:
060417,000050: # DXCH ARUPT T6RUPT LEAD IN AT LOCATION 4004.
060418,000051: # EXTEND
060419,000052: # DCA T6ADR
060420,000053: # DTCB
060421,000054:
060422,000055: # SUBROUTINES CALLED: DOT6RUPT CALLS T6JOBCHK.
060423,000056:
060424,000057: # NORMAL EXIT MODES: T6JOBCHK RETURNS TO L +1.
060425,000058: # DOT6RUPT TRANSFERS CONTROL TO RESUME.
060426,000059:
060427,000060: # ALARM/ABORT MODES: NONE.
060428,000061:
060429,000062: # INPUT: TIME6 NXT6ADR OUTPUT: TIME6 NXT6ADR CHANNEL 5
060430,000063: # T6NEXT T6NEXT +1 T6NEXT T6NEXT +1 CHANNEL 6
060431,000064: # T6FURTHA T6FURTHA +1 T6FURTHA T6FURTHA +1 BIT15/CH13
060432,000065:
060433,000066: # DEBRIS: T6JOBCHK CLOBBERS A. DOT6RUPT CLOBBERS NOTHING.
060434,000067:
060435,000068: 5744 BLOCK 02
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Page 1399
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060437,000070: 17,2000 BANK 17
060438,000071: 17,2000 SETLOC DAPS2
060439,000072: 17,2000 BANK
060440,000073: 17,2000 E6,1464 EBANK= T6NEXT
060441,000074: 17,2000 COUNT* $$/DAPT6
060442,000075:
060443,000076: 17,2000 10031 T6JOBCHK CCS TIME6 # CHECK TIME6 FOR WAITING T6RUPT:
060444,000077: 17,2001 00002 TC Q # NONE: CLOCK COUTING DOWN.
060445,000078: 17,2002 05677 TC CCSHOLE
060446,000079: 17,2003 02003 TC T6JOBCHK +3
060447,000080:
060448,000081: # CONTROL PASSES TO T6JOB ONLY WHEN C(TIME6) = -0 (I.E. WHEN A T6RUPT MUST BE PROCESSED).
060449,000082:
060450,000083: 17,2004 34733 T6JOB CAF POSMAX # DISABLE CLOCK: NEEDED SINCE RUPT OCCURS
060451,000084: 17,2005 00006 EXTEND # 1 DINC AFTER T6 = 77777. FOR 625 MUSECS
060452,000085: 17,2006 03013 WAND CHAN13 # MUST NOT HAVE T6 = +0 WITH ENABLE SET
060453,000086:
060454,000087: 17,2007 34733 CA POSMAX
060455,000088: 17,2010 22007 ZL
060456,000089: 17,2011 53467 DXCH T6FURTHA
060457,000090: 17,2012 53465 DXCH T6NEXT
060458,000091: 17,2013 23463 LXCH NXT6ADR
060459,000092: 17,2014 54031 TS TIME6
060460,000093:
060461,000094: 17,2015 67724 AD PRIO37
060462,000095: 17,2016 54000 TS A
060463,000096: 17,2017 12023 TCF ENABLET6
060464,000097: 17,2020 34733 CA POSMAX
060465,000098: 17,2021 54031 TS TIME6
060466,000099: 17,2022 12034 TCF GOCH56
060467,000100: 17,2023 34735 ENABLET6 CA BIT15
060468,000101: 17,2024 00006 EXTEND
060469,000102: 17,2025 05013 WOR CHAN13
060470,000103: 17,2026 31464 CA T6NEXT
060471,000104: 17,2027 67724 AD PRIO37
060472,000105: 17,2030 54000 TS A
060473,000106: 17,2031 12034 TCF GOCH56
060474,000107: 17,2032 34733 CA POSMAX
060475,000108: 17,2033 55464 TS T6NEXT
060476,000109: 17,2034 50001 GOCH56 INDEX L
060477,000110: 17,2035 15744 TCF WRITEP -1
060478,000111:
060479,000112: 5744 BLOCK 02
060480,000113: 4000 SETLOC FFTAG9
060481,000114: 4000 BANK
060482,000115: 5744 E6,1633 EBANK= CDUXD
060483,000116: 5744 COUNT* $$/DAPT6
060484,000117:
060485,000118: 5744 31470 CA NEXTP
060486,000119: 5745 00006 WRITEP EXTEND
060487,000120: 5746 01006 WRITE CHAN6
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Page 1400
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060489,000122: 5747 00002 TC Q
060490,000123:
060491,000124: 5750 31471 CA NEXTU
060492,000125: 5751 54001 WRITEU TS L
060493,000126: 5752 45765 CS 00314OCT
060494,000127: 5753 00006 EXTEND
060495,000128: 5754 02005 RAND CHAN5
060496,000129: 5755 60001 AD L
060497,000130: 5756 00006 EXTEND
060498,000131: 5757 01005 WRITE CHAN5
060499,000132: 5760 00002 TC Q
060500,000133:
060501,000134: 5761 31472 CA NEXTV
060502,000135: 5762 54001 WRITEV TS L
060503,000136: 5763 35765 CA 00314OCT
060504,000137: 5764 15753 TCF -9D
060505,000138: 5765 00314 00314OCT OCT 00314
060506,000139:
060507,000140: 17,2036 BANK 17
060508,000141: 17,2000 SETLOC DAPS2
060509,000142: 17,2000 BANK
060510,000143:
060511,000144: 17,2036 E6,1464 EBANK= T6NEXT
060512,000145: 17,2036 COUNT* $$/DAPT6
060513,000146:
060514,000147: 17,2036 22016 DOT6RUPT LXCH BANKRUPT # (INTERRUPT LEAD INS CONTINUED)
060515,000148: 17,2037 00006 EXTEND
060516,000149: 17,2040 22012 QXCH QRUPT
060517,000150:
060518,000151: 17,2041 02000 TC T6JOBCHK # CALL T6JOBCHK.
060519,000152:
060520,000153: 17,2042 15270 TCF RESUME # END TIME6 INTERRUPT PROCESSOR.
060521,000154:
End of include-file T6-RUPT_PROGRAMS.agc. Parent file is MAIN.agc