Source Code
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These source-code files are part of a reconstructed copy of Luminary 96, the
original release of the Apollo 11 Lunar Module (LM) Apollo Guidance Computer
(AGC) software.
The reconstruction began with reconstructed source code for Luminary 97. Changes
between revisions 96 and 97 were backed out, as described by anomal report LNY-59.
transcribed from a digitized copy of that program. The reconstruction was
verified by matching memory-bank checksums to those listed in drawing 2021152D.
Note that page numbers in the reconstructed code match those on the Luminary 099
revision 001 printout, although the added code would likely have changed page
numbers for a real Luminary 96 listing.
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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063845,000002: ## Copyright: Public domain.
063846,000003: ## Filename: SPS_BACK-UP_RCS_CONTROL.agc
063847,000004: ## Purpose: A section of Luminary revision 96.
063848,000005: ## It is part of the reconstructed source code for the
063849,000006: ## original release of the flight software for the Lunar
063850,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
063851,000008: ## The code has been recreated from a previously reconstructed
063852,000009: ## copy of Luminary 97 by undoing changes described in anomaly
063853,000010: ## report LNY-59. The code has been adapted such that the
063854,000011: ## resulting bugger words exactly match those specified for
063855,000012: ## Luminary 96 in NASA drawing 2021152D, which gives relatively
063856,000013: ## high confidence that the reconstruction is correct.
063857,000014: ## Reference: pp. 1507-1510
063858,000015: ## Assembler: yaYUL
063859,000016: ## Contact: Ron Burkey <info@sandroid.org>.
063860,000017: ## Website: www.ibiblio.org/apollo/index.html
063861,000018: ## Mod history: 2019-08-04 MAS Created from Luminary 97.
063862,000019:
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Page 1507
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063864,000021: # PROGRAM NAME: SPSRCS
063865,000022: # AUTHOR: EDGAR M. OSHIKA (AC ELECTRONICS)
063866,000023: # MODIFIED: TO RETURN TO ALL AXES VIA Q BY P. S. WEISSMAN, OCT 7, 1968
063867,000024: # MODIFIED TO IMPROVE BENDING STABILITY BY G. KALAN, FEB. 14, 1969
063868,000025:
063869,000026: # FUNCTIONAL DESCRIPTION:
063870,000027: # THIS PROGRAM CONTROLS THE FIRING OF ALL RCS JETS IN THE DOCKED CONFIGURATION ACCORDING TO THE FOLLOWING PHASE
063871,000028: # PLANE LOGIC.
063872,000029:
063873,000030: # 1. JET SENSE TEST (SPSRCS)
063874,000031: # IF JETS ARE FIRING NEGATIVELY, SET OLDSENSE NEGATIVE AND CONTINUE
063875,000032: # IF JETS ARE FIRING POSITIVELY, SET OLDSENSE POSITIVE AND CONTINUE
063876,000033: # IF JETS ARE NOT FIRING, SET OLDSENSE TO ZERO AND GO TO OUTER RATE LIMIT TEST
063877,000034:
063878,000035: # 2. RATE DEAD BAND TEST
063879,000036: # IF JETS ARE FIRING NEGATIVELY AND RATE IS GREATER THAN TARGET RATE, LEAVE
063880,000037: # JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
063881,000038: # IF JETS ARE FIRING POSITIVELY AND RATE IS LESS THAN TARGET RATE, LEAVE
063882,000039: # JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
063883,000040:
063884,000041: # 3. OUTER RATE LIMIT TEST (SPSSTART)
063885,000042: # IF MAGNITUDE OF EDOT IS GREATER THAN 1.73 DEG/SEC SET JET FIRING TIME
063886,000043: # TO REDUCE RATE AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
063887,000044:
063888,000045: # 4. COAST ZONE TEST
063889,000046: # 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-
063890,000047: # TIVE AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
063891,000048: # 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
063892,000049: # AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
063893,000050:
063894,000051: # 5. INHIBITION LOGIC
063895,000052: # IF OLDSENSE IS NON-ZERO:
063896,000053: # A) RETURN IF JET TIME HAS SAME SIGN AS OLDSENSE
063897,000054: # B) SET INHIBITION COUNTER* AND RETURN IF JET TIME IS ZERO
063898,000055: # C) SET INHIBITION COUNTER,* SET JET TIME TO ZERO AND RETURN IF SIGN
063899,000056: # OF JET TIME IS OPPOSITE TO THAT OF OLDSENSE
063900,000057: # IF OLDSENSE IS ZERO:
063901,000058: # A) RETURN IF INHIBITION COUNTER IS NOT POSITIVE
063902,000059: # B) SET JET TIME TO ZERO AND RETURN IF INHIBITION COUNTER IS POSITIVE
063903,000060: # *NOTE: INHIBITION COUNTERS CAN BE SET TO 4 OR 10 FOR THE P, AND UV AXES,
063904,000061: # RESPECTIVELY, IN SPSRCS. THEY ARE DECREMENTED BY ONE AT THE BEGINNING OF
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Page 1508
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063906,000063: # EACH DAP PASS.
063907,000064:
063908,000065: # THE MINIMUM PULSE WIDTH OF THIS CONTROLLER IS DETERMINED BY THE REPETITION RATE AT WHICH THIS ROUTINE IS CALLED
063909,000066: # AND IS NOMINALLY 100 MS FOR ALL AXES IN DRIFTING FLIGHT. DURING POWERED FLIGHT THE MINIMUM IS 100 MS FOR THE
063910,000067: # P AXIS AND 200 MS FOR THE CONTROL OF THE U AND V AXES.
063911,000068:
063912,000069: # CALLING SEQUENCE:
063913,000070: # INHINT
063914,000071: # TC IBNKCALL
063915,000072: # CADR SPSRCS
063916,000073:
063917,000074: # EXIT:
063918,000075: # TC Q
063919,000076:
063920,000077: # ALARM/ABORT MODE: NONE
063921,000078:
063922,000079: # SUBROUTINES CALLED: NONE
063923,000080:
063924,000081: # INPUT: E, EDOT
063925,000082: # TJP, TJV, TJU TJ MUST NOT BE NEGATIVE ZERO
063926,000083:
063927,000084: # OUTPUT: TJP, TJV, TJU
063928,000085:
063929,000086: 21,3646 BANK 21
063930,000087: 21,2000 SETLOC DAPS4
063931,000088: 21,2000 BANK
063932,000089:
063933,000090: 21,3646 COUNT* $$/DAPBU
063934,000091:
063935,000092: 21,3646 E6,1525 EBANK= TJU
063936,000093: 21,3646 00632 RATELIM2 OCT 00632 # 1.125 DEG/SEC
063937,000094: 21,3647 34736 POSTHRST CA HALF
063938,000095:
063939,000096: 21,3650 51505 NDX AXISCTR
063940,000097: 21,3651 55525 TS TJU
063941,000098: 21,3652 11745 CCS OLDSENSE
063942,000099: 21,3653 13673 TCF POSCHECK # JETS FIRING POSITIVELY
063943,000100: 21,3654 13676 TCF CTRCHECK # JETS OFF. CHECK INHIBITION CTR
063944,000101: 21,3655 51505 NEGCHECK INDEX AXISCTR # JETS FIRING NEGATIVELY
063945,000102: 21,3656 41525 CS TJU
063946,000103: 21,3657 10000 CCS A
063947,000104: 21,3660 00002 TC Q # RETURN
063948,000105: 21,3661 13663 TCF +2
063949,000106: 21,3662 13663 TCF +1 # JETS COMMANDED OFF. SET CTR AND RETURN
063950,000107: 21,3663 51505 SETCTR INDEX AXISCTR # JET FIRING REVERSAL COMMANDED. SET CTR,
063951,000108: 21,3664 33705 CA UTIME # SET JET TIME TO ZERO, AND RETURN
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Page 1509
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063953,000110: 21,3665 51505 INDEX AXISCTR
063954,000111: 21,3666 55770 TS UJETCTR
063955,000112: 21,3667 34755 ZAPTJ CA ZERO
063956,000113: 21,3670 51505 INDEX AXISCTR
063957,000114: 21,3671 55525 TS TJU
063958,000115: 21,3672 00002 TC Q
063959,000116: 21,3673 51505 POSCHECK INDEX AXISCTR
063960,000117: 21,3674 31525 CA TJU
063961,000118: 21,3675 13657 TCF NEGCHECK +2
063962,000119: 21,3676 51505 CTRCHECK INDEX AXISCTR # CHECK JET INHIBITION COUNTER
063963,000120: 21,3677 11770 CCS UJETCTR
063964,000121: 21,3700 13702 TCF +2
063965,000122: 21,3701 00002 TC Q # CTR IS NOT POSITIVE. RETURN
063966,000123: 21,3702 13667 TCF ZAPTJ # CTR IS POSITIVE. INHIBIT FIRINGS
063967,000124: 21,3703 00002 TC Q # CTR IS NOT POSITIVE. RETURN
063968,000125: 21,3704 00004 OCT 00004
063969,000126: 21,3705 00012 UTIME OCT 00012
063970,000127: 21,3706 00012 OCT 00012
063971,000128: 21,3707 E6,1745 OLDSENSE EQUALS DAPTREG1
063972,000129: 21,3707 44753 NEGFIRE CS ONE # JETS FIRING NEGATIVELY
063973,000130: 21,3710 55745 TS OLDSENSE
063974,000131: 21,3711 31427 CA EDOT
063975,000132: 21,3712 13716 TCF +4
063976,000133: 21,3713 34753 PLUSFIRE CA ONE
063977,000134: 21,3714 55745 TS OLDSENSE
063978,000135: 21,3715 41427 CS EDOT # RATE DEAD BAND TEST
063979,000136: 21,3716 22000 LXCH A
063980,000137: 21,3717 40111 CS DAPBOOLS # IF DRIFTBIT = 1, USE ZERO TARGET RATE
063981,000138: 21,3720 74744 MASK DRIFTBIT # IF DRIFTBIT = 0, USE 0.10 RATE TARGET
063982,000139: 21,3721 10000 CCS A
063983,000140: 21,3722 34767 CA RATEDB1
063984,000141: 21,3723 60001 AD L
063985,000142: 21,3724 00006 EXTEND
063986,000143: 21,3725 63735 BZMF SPSSTART
063987,000144: 21,3726 13652 TCF POSTHRST +3
063988,000145:
063989,000146: 21,3727 51505 SPSRCS INDEX AXISCTR # JET SENSE TEST
063990,000147: 21,3730 11525 CCS TJU
063991,000148: 21,3731 13713 TCF PLUSFIRE # JETS FIRING POSITIVELY
063992,000149: 21,3732 13734 TCF +2
063993,000150: 21,3733 13707 TCF NEGFIRE # JETS FIRING NEGATIVELY
063994,000151: 21,3734 55745 TS OLDSENSE # JETS OFF
063995,000152: 21,3735 31427 SPSSTART CA EDOT # OUTER RATE LIMIT TEST
063996,000153: 21,3736 00006 EXTEND
063997,000154: 21,3737 74766 MP RATELIM1
063998,000155: 21,3740 10000 CCS A
063999,000156: 21,3741 13760 TCF NEGTHRST # OUTER RATE LIMIT EXCEEDED
064000,000157: 21,3742 13744 TCF +2
064001,000158: 21,3743 13647 TCF POSTHRST # OUTER RATE LIMIT EXCEEDED
064002,000159: 21,3744 31427 CA EDOT # COAST ZONE TEST
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Page 1510
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064004,000161: 21,3745 61752 AD E
064005,000162: 21,3746 00006 EXTEND
064006,000163: 21,3747 71411 MP DKDB # PAD LOADED DEADBAND. FRESHSTART: 1.4 DEG
064007,000164: 21,3750 00006 EXTEND
064008,000165: 21,3751 13766 BZF TJZERO
064009,000166:
064010,000167: 21,3752 00006 EXTEND
064011,000168: 21,3753 63762 BZMF +7
064012,000169: 21,3754 31427 CA EDOT
064013,000170: 21,3755 63646 AD RATELIM2
064014,000171: 21,3756 00006 EXTEND
064015,000172: 21,3757 63766 BZMF TJZERO
064016,000173: 21,3760 44736 NEGTHRST CS HALF
064017,000174: 21,3761 13650 TCF POSTHRST +1
064018,000175: 21,3762 43646 +7 CS RATELIM2
064019,000176: 21,3763 61427 AD EDOT
064020,000177: 21,3764 00006 EXTEND
064021,000178: 21,3765 63647 BZMF POSTHRST
064022,000179: 21,3766 34755 TJZERO CA ZERO
064023,000180: 21,3767 13650 TCF POSTHRST +1
064024,000181:
064025,000182: 21,3770 4766 RATELIM1 = CALLCODE # = 00032, CORRESPONDING TO 1.73 DEG/SEC
064026,000183: 21,3770 4767 RATEDB1 = TBUILDFX # = 00045, CORRESPONDS TO 0.101 DEG/SEC
064027,000184:
End of include-file SPS_BACK-UP_RCS_CONTROL.agc. Parent file is MAIN.agc