Source Code
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This is a reconstruction of the AGC program Luminary 99 Rev 0. It was the third release
of the Lunar Module flight software targeted for use in Apollo 11, after Luminary 96 and 97.
A bug (which had been around since at least Apollo 10, Luminary 69) was
discovered in Rev 0 shortly before the Apollo 11 flight, resulting in a last minute
revision into Rev 1,
which is what actually flew rather than
the Rev 0 presented here. A hardcopy of Rev 0 is known to
exist — it belonged to AGC developer Allan Klumpp for many years — but
unfortunately the Virtual AGC Project has not had access to that hardcopy. Thus
the code you see here had been reconstructed (we believe accurately) rather than
transcribed. The first step of the reconstruction of the Rev 0 source code was
the transcription of the Rev 1 source code from a hardcopy in the MIT Museum collection.
The process of reverting the active portion of the source code (i.e., other than
program comments) from Rev 1 to Rev 0 was very minor, consisting
only of moving the position of the STARTSB1 label in
FRESH START AND RESTART. Allan had previously given
us the checksums of the memory banks of Rev 0, and we have verified the program presented here has checksums
identical to all banks of Allan's listing of Rev 0. The notations on Allan's Rev 0 program listing read,
in part:GAP: ASSEMBLE REVISION 099 OF AGC PROGRAM LUMINARY BY NASA 2021112-051 A single program comment is known to differ between Rev 0 and Rev 1, but these are harder to reconstruct and verify than changes to the active portion of the code. Thus it is possible that there are additional differences between the program comments in Rev 0 and Rev 1 that are unknown to us, and therefore are not reflected in the code presented here. |
066661,000002: ## Copyright: Public domain.
066662,000003: ## Filename: SPS_BACK-UP_RCS_CONTROL.agc
066663,000004: ## Purpose: Part of the reconstructed source code for LMY99 Rev 0,
066664,000005: ## otherwise known as Luminary Rev 99, the third release
066665,000006: ## of the Apollo Guidance Computer (AGC) software for Apollo 11.
066666,000007: ## It differs from LMY99 Rev 1 (the flown version) only in the
066667,000008: ## placement of a single label. The corrections shown here have
066668,000009: ## been verified to have the same bank checksums as AGC developer
066669,000010: ## Allan Klumpp's copy of Luminary Rev 99, and so are believed
066670,000011: ## to be accurate. This file is intended to be a faithful
066671,000012: ## recreation, except that the code format has been changed to
066672,000013: ## conform to the requirements of the yaYUL assembler rather than
066673,000014: ## the original YUL assembler.
066674,000015: ##
066675,000016: ## Assembler: yaYUL
066676,000017: ## Contact: Ron Burkey <info@sandroid.org>.
066677,000018: ## Website: www.ibiblio.org/apollo.
066678,000019: ## Pages: 1507-1510
066679,000020: ## Mod history: 2009-05-27 RSB Adapted from the corresponding
066680,000021: ## Luminary131 file, using page
066681,000022: ## images from Luminary 1A.
066682,000023: ## 2011-01-06 JL Fixed pseudo-label indentation.
066683,000024: ## 2016-12-18 RSB Proofed text comments with octopus/ProoferComments
066684,000025: ## and corrected the errors found.
066685,000026: ## 2017-08-01 MAS Created from LMY99 Rev 1.
066686,000027:
066687,000028: ## This source code has been transcribed or otherwise adapted from
066688,000029: ## digitized images of a hardcopy from the MIT Museum. The digitization
066689,000030: ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
066690,000031: ## the Museum. Many thanks to both. The images (with suitable reduction
066691,000032: ## in storage size and consequent reduction in image quality as well) are
066692,000033: ## available online at www.ibiblio.org/apollo. If for some reason you
066693,000034: ## find that the images are illegible, contact me at info@sandroid.org
066694,000035: ## about getting access to the (much) higher-quality images which Paul
066695,000036: ## actually created.
066696,000037: ##
066697,000038: ## The code has been modified to match LMY99 Revision 0, otherwise
066698,000039: ## known as Luminary Revision 99, the Apollo 11 software release preceeding
066699,000040: ## the listing from which it was transcribed. It has been verified to
066700,000041: ## contain the same bank checksums as AGC developer Allan Klumpp's listing
066701,000042: ## of Luminary Revision 99 (for which we do not have scans).
066702,000043: ##
066703,000044: ## Notations on Allan Klumpp's listing read, in part:
066704,000045: ##
066705,000046: ## ASSEMBLE REVISION 099 OF AGC PROGRAM LUMINARY BY NASA 2021112-51
066706,000047:
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Page 1507 |
066708,000049: # PROGRAM NAME: SPSRCS
066709,000050: # AUTHOR: EDGAR M. OSHIKA (AC ELECTRONICS)
066710,000051: # MODIFIED: TO RETURN TO ALL AXES VIA Q BY P. S. WEISSMAN, OCT 7, 1968
066711,000052: # MODIFIED TO IMPROVE BENDING STABILITY BY G. KALAN, FEB. 14, 1969
066712,000053:
066713,000054: # FUNCTIONAL DESCRIPTION:
066714,000055: # THIS PROGRAM CONTROLS THE FIRING OF ALL RCS JETS IN THE DOCKED CONFIGURATION ACCORDING TO THE FOLLOWING PHASE
066715,000056: # PLANE LOGIC.
066716,000057:
066717,000058: # 1. JET SENSE TEST (SPSRCS)
066718,000059: # IF JETS ARE FIRING NEGATIVELY, SET OLDSENSE NEGATIVE AND CONTINUE
066719,000060: # IF JETS ARE FIRING POSITIVELY, SET OLDSENSE POSITIVE AND CONTINUE
066720,000061: # IF JETS ARE NOT FIRING, SET OLDSENSE TO ZERO AND GO TO OUTER RATE LIMIT TEST
066721,000062:
066722,000063: # 2. RATE DEAD BAND TEST
066723,000064: # IF JETS ARE FIRING NEGATIVELY AND RATE IS GREATER THAN TARGET RATE, LEAVE
066724,000065: # JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
066725,000066: # IF JETS ARE FIRING POSITIVELY AND RATE IS LESS THAN TARGET RATE, LEAVE
066726,000067: # JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
066727,000068:
066728,000069: # 3. OUTER RATE LIMIT TEST (SPSSTART)
066729,000070: # IF MAGNITUDE OF EDOT IS GREATER THAN 1.73 DEG/SEC SET JET FIRING TIME
066730,000071: # TO REDUCE RATE AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
066731,000072:
066732,000073: # 4. COAST ZONE TEST
066733,000074: # IF STATE (E,EDOT) IS BELOW LINE E + 4 X EDOT > -1.4 DEG AND EDOT IS LESS THAN 1.30 DEG/SEC SET JET TIME POSI-
066734,000075: # TIVE AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
066735,000076: # IF STATE IS ABOVE LINE E + 4 X EDOT > +1.4 DEG AND EDOT IS GREATER THAN -1.30 DEG/SEC, SET JET TIME NEGATIVE
066736,000077: # AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
066737,000078:
066738,000079: # 5. INHIBITION LOGIC
066739,000080: # IF OLDSENSE IS NON-ZERO:
066740,000081: # A) RETURN IF JET TIME HAS SAME SIGN AS OLDSENSE
066741,000082: # B) SET INHIBITION COUNTER* AND RETURN IF JET TIME IS ZERO
066742,000083: # C) SET INHIBITION COUNTER,* SET JET TIME TO ZERO AND RETURN IF SIGN
066743,000084: # OF JET TIME IS OPPOSITE TO THAT OF OLDSENSE
066744,000085: # IF OLDSENSE IS ZERO:
066745,000086: # A) RETURN IF INHIBITION COUNTER IS NOT POSITIVE
066746,000087: # B) SET JET TIME TO ZERO AND RETURN IF INHIBITION COUNTER IS POSITIVE
066747,000088: # *NOTE: INHIBITION COUNTERS CAN BE SET TO 4 OR 10 FOR THE P, AND UV AXES,
066748,000089: # RESPECTIVELY, IN SPSRCS. THEY ARE DECREMENTED BY ONE AT THE BEGINNING OF
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Page 1508 |
066750,000091: # EACH DAP PASS.
066751,000092:
066752,000093: # THE MINIMUM PULSE WIDTH OF THIS CONTROLLER IS DETERMINED BY THE REPETITION RATE AT WHICH THIS ROUTINE IS CALLED
066753,000094: # AND IS NOMINALLY 100 MS FOR ALL AXES IN DRIFTING FLIGHT. DURING POWERED FLIGHT THE MINIMUM IS 100 MS FOR THE
066754,000095: # P AXIS AND 200 MS FOR THE CONTROL OF THE U AND V AXES.
066755,000096:
066756,000097: # CALLING SEQUENCE:
066757,000098: # INHINT
066758,000099: # TC IBNKCALL
066759,000100: # CADR SPSRCS
066760,000101:
066761,000102: # EXIT:
066762,000103: # TC Q
066763,000104:
066764,000105: # ALARM/ABORT MODE: NONE
066765,000106:
066766,000107: # SUBROUTINES CALLED: NONE
066767,000108:
066768,000109: # INPUT: E, EDOT
066769,000110: # TJP, TJV, TJU TJ MUST NOT BE NEGATIVE ZERO
066770,000111:
066771,000112: # OUTPUT: TJP, TJV, TJU
066772,000113:
066773,000114: 21,3646 BANK 21
066774,000115: 21,2000 SETLOC DAPS4
066775,000116: 21,2000 BANK
066776,000117:
066777,000118: 21,3646 COUNT* $$/DAPBU
066778,000119:
066779,000120: 21,3646 E6,1525 EBANK= TJU
066780,000121: 21,3646 00632 RATELIM2 OCT 00632 # 1.125 DEG/SEC
066781,000122: 21,3647 34736 POSTHRST CA HALF
066782,000123:
066783,000124: 21,3650 51505 NDX AXISCTR
066784,000125: 21,3651 55525 TS TJU
066785,000126: 21,3652 11745 CCS OLDSENSE
066786,000127: 21,3653 13673 TCF POSCHECK # JETS FIRING POSITIVELY
066787,000128: 21,3654 13676 TCF CTRCHECK # JETS OFF. CHECK INHIBITION CTR
066788,000129: 21,3655 51505 NEGCHECK INDEX AXISCTR # JETS FIRING NEGATIVELY
066789,000130: 21,3656 41525 CS TJU
066790,000131: 21,3657 10000 CCS A
066791,000132: 21,3660 00002 TC Q # RETURN
066792,000133: 21,3661 13663 TCF +2
066793,000134: 21,3662 13663 TCF +1 # JETS COMMANDED OFF. SET CTR AND RETURN
066794,000135: 21,3663 51505 SETCTR INDEX AXISCTR # JET FIRING REVERSAL COMMANDED. SET CTR,
066795,000136: 21,3664 33705 CA UTIME # SET JET TIME TO ZERO, AND RETURN
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Page 1509 |
066797,000138: 21,3665 51505 INDEX AXISCTR
066798,000139: 21,3666 55770 TS UJETCTR
066799,000140: 21,3667 34755 ZAPTJ CA ZERO
066800,000141: 21,3670 51505 INDEX AXISCTR
066801,000142: 21,3671 55525 TS TJU
066802,000143: 21,3672 00002 TC Q
066803,000144: 21,3673 51505 POSCHECK INDEX AXISCTR
066804,000145: 21,3674 31525 CA TJU
066805,000146: 21,3675 13657 TCF NEGCHECK +2
066806,000147: 21,3676 51505 CTRCHECK INDEX AXISCTR # CHECK JET INHIBITION COUNTER
066807,000148: 21,3677 11770 CCS UJETCTR
066808,000149: 21,3700 13702 TCF +2
066809,000150: 21,3701 00002 TC Q # CTR IS NOT POSITIVE. RETURN
066810,000151: 21,3702 13667 TCF ZAPTJ # CTR IS POSITIVE. INHIBIT FIRINGS
066811,000152: 21,3703 00002 TC Q # CTR IS NOT POSITIVE. RETURN
066812,000153: 21,3704 00004 OCT 00004
066813,000154: 21,3705 00012 UTIME OCT 00012
066814,000155: 21,3706 00012 OCT 00012
066815,000156: 21,3707 E6,1745 OLDSENSE EQUALS DAPTREG1
066816,000157: 21,3707 44753 NEGFIRE CS ONE # JETS FIRING NEGATIVELY
066817,000158: 21,3710 55745 TS OLDSENSE
066818,000159: 21,3711 31427 CA EDOT
066819,000160: 21,3712 13716 TCF +4
066820,000161: 21,3713 34753 PLUSFIRE CA ONE
066821,000162: 21,3714 55745 TS OLDSENSE
066822,000163: 21,3715 41427 CS EDOT # RATE DEAD BAND TEST
066823,000164: 21,3716 22000 LXCH A
066824,000165: 21,3717 40111 CS DAPBOOLS # IF DRIFTBIT = 1, USE ZERO TARGET RATE
066825,000166: 21,3720 74744 MASK DRIFTBIT # IF DRIFTBIT = 0, USE 0.10 RATE TARGET
066826,000167: 21,3721 10000 CCS A
066827,000168: 21,3722 34767 CA RATEDB1
066828,000169: 21,3723 60001 AD L
066829,000170: 21,3724 00006 EXTEND
066830,000171: 21,3725 63735 BZMF SPSSTART
066831,000172: 21,3726 13652 TCF POSTHRST +3
066832,000173:
066833,000174: 21,3727 51505 SPSRCS INDEX AXISCTR # JET SENSE TEST
066834,000175: 21,3730 11525 CCS TJU
066835,000176: 21,3731 13713 TCF PLUSFIRE # JETS FIRING POSITIVELY
066836,000177: 21,3732 13734 TCF +2
066837,000178: 21,3733 13707 TCF NEGFIRE # JETS FIRING NEGATIVELY
066838,000179: 21,3734 55745 TS OLDSENSE # JETS OFF
066839,000180: 21,3735 31427 SPSSTART CA EDOT # OUTER RATE LIMIT TEST
066840,000181: 21,3736 00006 EXTEND
066841,000182: 21,3737 74766 MP RATELIM1
066842,000183: 21,3740 10000 CCS A
066843,000184: 21,3741 13760 TCF NEGTHRST # OUTER RATE LIMIT EXCEEDED
066844,000185: 21,3742 13744 TCF +2
066845,000186: 21,3743 13647 TCF POSTHRST # OUTER RATE LIMIT EXCEEDED
066846,000187: 21,3744 31427 CA EDOT # COAST ZONE TEST
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Page 1510 |
066848,000189: 21,3745 61752 AD E
066849,000190: 21,3746 00006 EXTEND
066850,000191: 21,3747 71411 MP DKDB # PAD LOADED DEADBAND. FRESHSTART: 1.4 DEG
066851,000192: 21,3750 00006 EXTEND
066852,000193: 21,3751 13766 BZF TJZERO
066853,000194:
066854,000195: 21,3752 00006 EXTEND
066855,000196: 21,3753 63762 BZMF +7
066856,000197: 21,3754 31427 CA EDOT
066857,000198: 21,3755 63646 AD RATELIM2
066858,000199: 21,3756 00006 EXTEND
066859,000200: 21,3757 63766 BZMF TJZERO
066860,000201: 21,3760 44736 NEGTHRST CS HALF
066861,000202: 21,3761 13650 TCF POSTHRST +1
066862,000203: 21,3762 43646 +7 CS RATELIM2
066863,000204: 21,3763 61427 AD EDOT
066864,000205: 21,3764 00006 EXTEND
066865,000206: 21,3765 63647 BZMF POSTHRST
066866,000207: 21,3766 34755 TJZERO CA ZERO
066867,000208: 21,3767 13650 TCF POSTHRST +1
066868,000209:
066869,000210: 21,3770 4766 RATELIM1 = CALLCODE # = 00032, CORRESPONDING TO 1.73 DEG/SEC
066870,000211: 21,3770 4767 RATEDB1 = TBUILDFX # = 00045, CORRESPONDS TO 0.101 DEG/SEC
066871,000212:
End of include-file SPS_BACK-UP_RCS_CONTROL.agc. Parent file is MAIN.agc