Source Code
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These source code files are a reconstruction of Sundance, the Apollo 9 LM (Lunar Module) AGC
(Apollo Guidance Computer) flight software, created from binary dumps of original core rope
program modules, as follows:
Since only binary dumps (rather than listings) of Sundance are available as source material, all comments and labels are approximate. They have been taken from other AGC programs where possible, or, in some places, written from scratch to match what we believe would have been in the original listing. |
011703,000002: ## Copyright: Public domain.
011704,000003: ## Filename: LEM_GEOMETRY.agc
011705,000004: ## Purpose: A section of a reconstructed, mixed version of Sundance
011706,000005: ## It is part of the reconstructed source code for the Lunar
011707,000006: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 9.
011708,000007: ## No original listings of this program are available;
011709,000008: ## instead, this file was created via disassembly of dumps
011710,000009: ## of various revisions of Sundance core rope modules.
011711,000010: ## Assembler: yaYUL
011712,000011: ## Contact: Ron Burkey <info@sandroid.org>.
011713,000012: ## Website: www.ibiblio.org/apollo/index.html
011714,000013: ## Mod history: 2020-06-17 MAS Created from Luminary 69.
011715,000014: ## 2021-05-30 ABS Replaced use of ANTENBIT with BIT12 to match
011716,000015: ## Luminary 69.
011717,000016:
011718,000017: ## Sundance 302
011719,000018:
011720,000019: 23,2000 BANK 23
011721,000020: 13,2000 SETLOC LEMGEOM
011722,000021: 13,2000 BANK
011723,000022:
011724,000023: 13,2042 30,2000 SBANK= LOWSUPER
011725,000024: 13,2042 E5,1642 EBANK= XSM
011726,000025:
011727,000026: # THESE TWO ROUTINES COMPUTE THE ACTUAL STATE VECTOR FOR LM,CSM BY ADDING
011728,000027: # THE CONIC R,V AND THE DEVIATIONSR,V. THE STATE VECTORS ARE CONVERTED TO
011729,000028: # METERS B-29 AND METERS/CSEC B-7 AND STORED APPROPRIATELY IN RN,VN OR
011730,000029: # R-OTHER , V-OTHER FOR DOWNLINK. THE ROUTINES NAMES ARE SWITCHED IN THE
011731,000030: # OTHER VEHICLES COMPUTER.
011732,000031:
011733,000032: # INPUT
011734,000033: # STATE VECTOR IN TEMPORARY STORAGE AREA
011735,000034: # IF STATE VECTOR IS SCALED POS B27 AND VEL B5
011736,000035: # SET X2 TO +2
011737,000036: # IF STATE VECTOR IS SCALED POS B29 AND VEL B7
011738,000037: # SET X2 TO 0
011739,000038:
011740,000039: # OUTPUT
011741,000040: # R(T) IN RN, V(T) IN VN, T IN PIPTIME
011742,000041: # OR
011743,000042: # R(T) IN R-OTHER, V(T) IN V-OTHER (T IS DEFINED BY T-OTHER)
011744,000043:
011745,000044: 13,2042 COUNT* $$/GEOM
011746,000045: 13,2042 43414 SVDWN2 BOF RVQ # SW=1=AVETOMID DOING W-MATRIX INTEG.
011747,000046: 13,2043 04756 AVEMIDSW
011748,000047: 13,2044 26045 +1
011749,000048: 13,2045 53775 VLOAD VSL*
011750,000049: 13,2046 01521 TDELTAV
011751,000050: 13,2047 57605 0 -7,2
011752,000051: 13,2050 53655 VAD VSL*
011753,000052: 13,2051 01535 RCV
011754,000053: 13,2052 57576 0,2
011755,000054: 13,2053 25220 STOVL RN
011756,000055: 13,2054 01527 TNUV
011757,000056: 13,2055 53257 VSL* VAD
011758,000057: 13,2056 57602 0 -4,2
011759,000058: 13,2057 01543 VCV
011760,000059: 13,2060 77657 VSL*
011761,000060: 13,2061 57576 0,2
011762,000061: 13,2062 15226 STODL VN
011763,000062: 13,2063 01517 TET
011764,000063: 13,2064 01234 STORE PIPTIME
011765,000064: 13,2065 77616 RVQ
011766,000065: 13,2066 53775 SVDWN1 VLOAD VSL*
011767,000066: 13,2067 01521 TDELTAV
011768,000067: 13,2070 57605 0 -7,2
011769,000068: 13,2071 53655 VAD VSL*
011770,000069: 13,2072 01535 RCV
011771,000070: 13,2073 57576 0,2
011772,000071: 13,2074 25722 STOVL R-OTHER
011773,000072: 13,2075 01527 TNUV
011774,000073: 13,2076 53257 VSL* VAD
011775,000074: 13,2077 57602 0 -4,2
011776,000075: 13,2100 01543 VCV
011777,000076: 13,2101 77657 VSL*
011778,000077: 13,2102 57576 0,2
011779,000078: 13,2103 01730 STORE V-OTHER
011780,000079: 13,2104 77616 RVQ
011781,000080:
011782,000081: # THE FOLLOWING ROUTINE TAKES A HALF UNIT TARGET VECTOR REFERRED TO NAV BASE COORDINATES AND FINDS BOTH
011783,000082: # GIMBAL ORIENTATIONS AT WHICH THE RR MIGHT SIGHT THE TARGET. THE GIMBAL ANGLES CORRESPONDING TO THE PRESENT MODE
011784,000083: # ARE LEFT IN MODEA AND THOSE WHICH WOULD BE USED AFTER A REMODE IN MODEB. THIS ROUTINE ASSUMES MODE 1 IS TRUNNION
011785,000084: # ANGLE LESS THAN 90 DEGS IN ABS VALUE WITH ARBITRARY SHAFT, WITH A CORRESPONDING DEFINITION FOR MODE 2. MODE
011786,000085: # SELECTION AND LIMIT CHECKING ARE DONE ELSEWHERE.
011787,000086:
011788,000087: # THE MODE 1 CONFIGURATION IS CALCULATED FROM THE VECTOR AND THEN MODE 2 IS FOUND USING THE RELATIONS
011789,000088:
011790,000089: # S(2) = 180 + S(1)
011791,000090: # T(2) = 180 - T(1)
011792,000091:
011793,000092: # THE VECTOR ARRIVES IN MPAC WHERE TRG*SMNG OR *SMNB* WILL HAVE LEFT IT.
011794,000093:
011795,000094: 13,2105 00041 RRANGLES STORE 32D
011796,000095: 13,2106 57545 DLOAD DCOMP # SINCE WE WILL FIND THE MODE 1 SHAFT
011797,000096: 13,2107 00043 34D # ANGLE LATER, WE CAN FIND THE MODE 1
011798,000097: 13,2110 67401 SETPD ASIN # TRUNNION BY SIMPLY TAKING THE ARCSIN OF
011799,000098: 13,2111 00001 0 # THE Y COMPONENT, THE ASIN GIVING AN
011800,000099: 13,2112 44206 PUSH BDSU # ANSWER WHOSE ABS VAL IS LESS THAN 90 DEG
011801,000100: 13,2113 22274 LODPHALF
011802,000101: 13,2114 14005 STODL 4 # MODE 2 TRUNNION TO 4.
011803,000102:
011804,000103: 13,2115 22276 LO6ZEROS
011805,000104: 13,2116 24043 STOVL 34D # UNIT THE PROJECTION OF THE VECTOR
011806,000105: 13,2117 00041 32D # IN THE X-Z PLANE
011807,000106: 13,2120 41056 UNIT BOVB # IF OVERFLOW, TARGET VECTOR IS ALONG Y
011808,000107: 13,2121 52400 LUNDESCH # CALL FOR MANEUVER UNLESS ON LUNAR SURF
011809,000108: 13,2122 14041 STODL 32D # PROJECTION VECTOR.
011810,000109: 13,2123 00041 32D
011811,000110: 13,2124 44142 SR1 STQ
011812,000111: 13,2125 00051 S2
011813,000112: 13,2126 14023 STODL SINTH # USE ARCTRIG SINCE SHAFT COULD BE ARB.
011814,000113: 13,2127 00045 36D
011815,000114: 13,2130 77742 SR1
011816,000115: 13,2131 34021 STCALL COSTH
011817,000116: 13,2132 47030 ARCTRIG
011818,000117: 13,2133 43206 PUSH DAD # MODE 1 SHAFT TO 2.
011819,000118: 13,2134 22274 LODPHALF
011820,000119: 13,2135 24007 STOVL 6
011821,000120: 13,2136 00005 4
011822,000121: 13,2137 77634 RTB # FIND MODE 2 CDU ANGLES.
011823,000122: 13,2140 21533 2V1STO2S
011824,000123: 13,2141 25115 STOVL MODEB
011825,000124: 13,2142 00001 0
011826,000125: 13,2143 77634 RTB # MODE 1 ANGLES TO MODE A.
011827,000126: 13,2144 21533 2V1STO2S
011828,000127: 13,2145 01113 STORE MODEA
011829,000128: 13,2146 77776 EXIT
011830,000129:
011831,000130: 13,2147 41101 CS RADMODES # SWAP MODEA AND MODEB IF RR IN MODE 2.
011832,000131: 13,2150 75013 MASK BIT12
011833,000132: 13,2151 10000 CCS A
011834,000133: 13,2152 12156 TCF +4
011835,000134:
011836,000135: 13,2153 53113 DXCH MODEA
011837,000136: 13,2154 53115 DXCH MODEB
011838,000137: 13,2155 53113 DXCH MODEA
011839,000138:
011840,000139: 13,2156 06014 TC INTPRET
011841,000140: 13,2157 77650 GOTO
011842,000141: 13,2160 00051 S2
011843,000142: # GIVEN RR TRUNNION AND SHAFT (T,S) IN TANGNB,+1, FIND THE ASSOCIATED
011844,000143: # LINE OF SIGHT IN NAV BASE AXES. THE HALF UNIT VECTOR, .5(SIN(S)COS(T),
011845,000144: # -SIN(T),COS(S)COS(T)) IS LEFT IN MPAC AND 32D.
011846,000145:
011847,000146: 23,2000 SETLOC INFLIGHT
011848,000147: 23,2000 BANK
011849,000148:
011850,000149: 23,2000 COUNT* $$/GEOM
011851,000150:
011852,000151: 23,2000 47135 RRNB SLOAD RTB
011853,000152: 23,2001 03744 TANGNB
011854,000153: 23,2002 21457 CDULOGIC
011855,000154: 23,2003 41401 SETPD PUSH # TRUNNION ANGLE TO 0
011856,000155: 23,2004 00001 0
011857,000156: 23,2005 57556 SIN DCOMP
011858,000157: 23,2006 14043 STODL 34D # Y COMPONENT
011859,000158:
011860,000159: 23,2007 41546 COS PUSH # .5 COS(T) TO 0
011861,000160: 23,2010 47135 SLOAD RTB
011862,000161: 23,2011 03745 TANGNB +1
011863,000162: 23,2012 21457 CDULOGIC
011864,000163: 23,2013 71406 PUSH COS # SHAFT ANGLE TO 2
011865,000164: 23,2014 72405 DMP SL1
011866,000165: 23,2015 00001 0
011867,000166: 23,2016 14045 STODL 36D # Z COMPONENT
011868,000167:
011869,000168: 23,2017 41356 SIN DMP
011870,000169: 23,2020 77752 SL1
011871,000170: 23,2021 24041 STOVL 32D
011872,000171: 23,2022 00041 32D
011873,000172: 23,2023 77616 RVQ
End of include-file LEM_GEOMETRY.agc. Parent file is MAIN.agc