Notations on the program listing read, in part:
GAP: ASSEMBLE REVISION 116 OF AGC PROGRAM LUMINARY BY NASA 2021112-071 19:09 AUG. 11,1969Note that the date is the date of the printout, not the date of the program revision.
Source Code
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These source-code files derive from a printout of Luminary 116 (the Apollo 12
Lunar Module guidance computer program), from the personal library of
original AGC developer Don Eyles, digitally photographed at archive.org,
financially sponsored by Ron Burkey, and transcribed to source code by a
team of volunteers. This colorized, syntax-highlighted form was created
by assembling that transcribed source code. Note that the full page images
are available on the
Virtual AGC project page at archive.org, while reduced-size images
are presented at the VirtualAGC project website. Report or fix any
transcription errors at
the Virtual AGC project code repository. Notations on the program listing read, in part: GAP: ASSEMBLE REVISION 116 OF AGC PROGRAM LUMINARY BY NASA 2021112-071 19:09 AUG. 11,1969Note that the date is the date of the printout, not the date of the program revision. |
013480,000002: ## Copyright: Public domain.
013481,000003: ## Filename: LEM_GEOMETRY.agc
013482,000004: ## Purpose: A section of Luminary revision 116.
013483,000005: ## It is part of the source code for the Lunar Module's (LM)
013484,000006: ## Apollo Guidance Computer (AGC) for Apollo 12.
013485,000007: ## This file is intended to be a faithful transcription, except
013486,000008: ## that the code format has been changed to conform to the
013487,000009: ## requirements of the yaYUL assembler rather than the
013488,000010: ## original YUL assembler.
013489,000011: ## Reference: pp. 321-326
013490,000012: ## Assembler: yaYUL
013491,000013: ## Contact: Ron Burkey <info@sandroid.org>.
013492,000014: ## Website: www.ibiblio.org/apollo/index.html
013493,000015: ## Mod history: 2017-01-22 MAS Created from Luminary 99.
013494,000016: ## 2017-03-07 RSB Transcribed, and then proofed comment-text using
013495,000017: ## 3-way diff vs Luminary 99 and Luminary 131.
013496,000018: ## (Admittedly, the former is more for detecting errors
013497,000019: ## in Luminary 99 than the other way around.)
013498,000020:
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Page 321 |
013500,000022: 23,2041 BANK 23
013501,000023: 13,2000 SETLOC LEMGEOM
013502,000024: 13,2000 BANK
013503,000025:
013504,000026: 13,2070 30,2000 SBANK= LOWSUPER
013505,000027: 13,2070 E5,1642 EBANK= XSM
013506,000028:
013507,000029: # THESE TWO ROUTINES COMPUTE THE ACTUAL STATE VECTOR FOR LM,CSM BY ADDING
013508,000030: # THE CONIC R,V AND THE DEVIATIONSR,V. THE STATE VECTORS ARE CONVERTED TO
013509,000031: # METERS B-29 AND METERS/CSEC B-7 AND STORED APPROPRIATELY IN RN,VN OR
013510,000032: # R-OTHER,V-OTHER FOR DOWNLINK. THE ROUTINES NAMES ARE SWITCHED IN THE
013511,000033: # OTHER VEHICLES COMPUTER.
013512,000034:
013513,000035: # INPUT
013514,000036: # STATE VECTOR IN TEMPORARY STORAGE AREA
013515,000037: # IF STATE VECTOR IS SCALED POS B27 AND VEL B5
013516,000038: # SET X2 TO +2
013517,000039: # IF STATE VECTOR IS SCALED POS B29 AND VEL B7
013518,000040: # SET X2 TO 0
013519,000041:
013520,000042: # OUTPUT
013521,000043: # R(T) IN RN, V(T) IN VN, T IN PIPTIME
013522,000044: # OR
013523,000045: # R(T) IN R-OTHER, V(T) IN V-OTHER (T IS DEFINED BY T-OTHER)
013524,000046:
013525,000047: 13,2070 COUNT* $$/GEOM
013526,000048: 13,2070 43414 SVDWN2 BOF RVQ # SW=1=AVETOMID DOING W-MATRIX INTEG.
013527,000049: 13,2071 04756 AVEMIDSW
013528,000050: 13,2072 26073 +1
013529,000051: 13,2073 53775 VLOAD VSL*
013530,000052: 13,2074 01521 TDELTAV
013531,000053: 13,2075 57605 0 -7,2
013532,000054: 13,2076 53655 VAD VSL*
013533,000055: 13,2077 01535 RCV
013534,000056: 13,2100 57576 0,2
013535,000057: 13,2101 25220 STOVL RN
013536,000058: 13,2102 01527 TNUV
013537,000059: 13,2103 53257 VSL* VAD
013538,000060: 13,2104 57602 0 -4,2
013539,000061: 13,2105 01543 VCV
013540,000062: 13,2106 77657 VSL*
013541,000063: 13,2107 57576 0,2
013542,000064: 13,2110 15226 STODL VN
013543,000065: 13,2111 01517 TET
013544,000066: 13,2112 01234 STORE PIPTIME
013545,000067: 13,2113 77616 RVQ
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Page 322 |
013547,000069: 13,2114 53775 SVDWN1 VLOAD VSL*
013548,000070: 13,2115 01521 TDELTAV
013549,000071: 13,2116 57605 0 -7,2
013550,000072: 13,2117 53655 VAD VSL*
013551,000073: 13,2120 01535 RCV
013552,000074: 13,2121 57576 0,2
013553,000075: 13,2122 25720 STOVL R-OTHER
013554,000076: 13,2123 01527 TNUV
013555,000077: 13,2124 53257 VSL* VAD
013556,000078: 13,2125 57602 0 -4,2
013557,000079: 13,2126 01543 VCV
013558,000080: 13,2127 77657 VSL*
013559,000081: 13,2130 57576 0,2
013560,000082: 13,2131 01726 STORE V-OTHER
013561,000083: 13,2132 77616 RVQ
013562,000084:
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Page 323 |
013564,000086: # THE FOLLOWING ROUTINE TAKES A HALF UNIT TARGET VECTOR REFERRED TO NAV BASE COORDINATES AND FINDS BOTH
013565,000087: # GIMBAL ORIENTATIONS AT WHICH THE RR MIGHT SIGHT THE TARGET. THE GIMBAL ANGLES CORRESPONDING TO THE PRESENT MODE
013566,000088: # ARE LEFT IN MODEA AND THOSE WHICH WOULD BE USED AFTER A REMODE IN MODEB. THIS ROUTINE ASSUMES MODE 1 IS TRUNNION
013567,000089: # ANGLE LESS THAN 90 DEGS IN ABS VALUE WITH ARBITRARY SHAFT, WITH A CORRESPONDING DEFINITION FOR MODE 2. MODE
013568,000090: # SELECTION AND LIMIT CHECKING ARE DONE ELSEWHERE.
013569,000091:
013570,000092: # THE MODE 1 CONFIGURATION IS CALCULATED FROM THE VECTOR AND THEN MODE 2 IS FOUND USING THE RELATIONS
013571,000093:
013572,000094: # S(2) = 180 + S(1)
013573,000095: # T(2) = 180 - T(1)
013574,000096:
013575,000097: # THE VECTOR ARRIVES IN MPAC WHERE TRG*SMNG OR *SMNB* WILL HAVE LEFT IT.
013576,000098:
013577,000099: 13,2133 00041 RRANGLES STORE 32D
013578,000100: 13,2134 57545 DLOAD DCOMP # SINCE WE WILL FIND THE MODE 1 SHAFT
013579,000101: 13,2135 00043 34D # ANGLE LATER, WE CAN FIND THE MODE 1
013580,000102: 13,2136 67401 SETPD ASIN # TRUNNION BY SIMPLY TAKING THE ARCSIN OF
013581,000103: 13,2137 00001 0 # THE Y COMPONENT, THE ASIN GIVING AN
013582,000104: 13,2140 44206 PUSH BDSU # ANSWER WHOSE ABS VAL IS LESS THAN 90 DEG
013583,000105: 13,2141 24005 LODPHALF
013584,000106: 13,2142 14005 STODL 4 # MODE 2 TRUNNION TO 4.
013585,000107:
013586,000108: 13,2143 24007 LO6ZEROS
013587,000109: 13,2144 24043 STOVL 34D # UNIT THE PROJECTION OF THE VECTOR
013588,000110: 13,2145 00041 32D # IN THE X-Z PLANE
013589,000111: 13,2146 41056 UNIT BOVB # IF OVERFLOW,TARGET VECTOR IS ALONG Y
013590,000112: 13,2147 52432 LUNDESCH # CALL FOR MANEUVER UNLESS ON LUNAR SURF
013591,000113: 13,2150 14041 STODL 32D # PROJECTION VECTOR.
013592,000114: 13,2151 00041 32D
013593,000115: 13,2152 44142 SR1 STQ
013594,000116: 13,2153 00051 S2
013595,000117: 13,2154 14023 STODL SINTH # USE ARCTRIG SINCE SHAFT COULD BE ARB.
013596,000118: 13,2155 00045 36D
013597,000119: 13,2156 77742 SR1
013598,000120: 13,2157 34021 STCALL COSTH
013599,000121: 13,2160 47322 ARCTRIG
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Page 324 |
013601,000123: 13,2161 43206 PUSH DAD # MODE 1 SHAFT TO 2.
013602,000124: 13,2162 24005 LODPHALF
013603,000125: 13,2163 24007 STOVL 6
013604,000126: 13,2164 00005 4
013605,000127: 13,2165 77634 RTB # FIND MODE 2 CDU ANGLES.
013606,000128: 13,2166 21636 2V1STO2S
013607,000129: 13,2167 25111 STOVL MODEB
013608,000130: 13,2170 00001 0
013609,000131: 13,2171 77634 RTB # MODE 1 ANGLES TO MODE A.
013610,000132: 13,2172 21636 2V1STO2S
013611,000133: 13,2173 01107 STORE MODEA
013612,000134: 13,2174 77776 EXIT
013613,000135:
013614,000136: 13,2175 40110 CS RADMODES # SWAP MODEA AND MODEB IF RR IN MODE 2.
013615,000137: 13,2176 74740 MASK ANTENBIT
013616,000138: 13,2177 10000 CCS A
013617,000139: 13,2200 12204 TCF +4
013618,000140:
013619,000141: 13,2201 53107 DXCH MODEA
013620,000142: 13,2202 53111 DXCH MODEB
013621,000143: 13,2203 53107 DXCH MODEA
013622,000144:
013623,000145: 13,2204 06042 TC INTPRET
013624,000146: 13,2205 77650 GOTO
013625,000147: 13,2206 00051 S2
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Page 325 |
013627,000149: # GIVEN RR TRUNNION AND SHAFT (T,S) IN TANGNB,+1,FIND THE ASSOCIATED
013628,000150: # LINE OF SIGHT IN NAV BASE AXES. THE HALF UNIT VECTOR, .5(SIN(S)COS(T),
013629,000151: # -SIN(T),COS(S)COS(T)) IS LEFT IN MPAC AND 32D.
013630,000152:
013631,000153: 23,2000 SETLOC INFLIGHT
013632,000154: 23,2000 BANK
013633,000155:
013634,000156: 23,2041 COUNT* $$/GEOM
013635,000157:
013636,000158: 23,2041 47135 RRNB SLOAD RTB
013637,000159: 23,2042 03753 TANGNB
013638,000160: 23,2043 21577 CDULOGIC
013639,000161: 23,2044 41401 SETPD PUSH # TRUNNION ANGLE TO 0
013640,000162: 23,2045 00001 0
013641,000163: 23,2046 57556 SIN DCOMP
013642,000164: 23,2047 14043 STODL 34D # Y COMPONENT
013643,000165:
013644,000166: 23,2050 41546 COS PUSH # .5 COS(T) TO 0
013645,000167: 23,2051 47135 SLOAD RTB
013646,000168: 23,2052 03754 TANGNB +1
013647,000169: 23,2053 21577 CDULOGIC
013648,000170: 23,2054 71406 RRNB1 PUSH COS # SHAFT ANGLE TO 2
013649,000171: 23,2055 72405 DMP SL1
013650,000172: 23,2056 00001 0
013651,000173: 23,2057 14045 STODL 36D # Z COMPONENT
013652,000174:
013653,000175: 23,2060 41356 SIN DMP
013654,000176: 23,2061 77752 SL1
013655,000177: 23,2062 24041 STOVL 32D
013656,000178: 23,2063 00041 32D
013657,000179: 23,2064 77616 RVQ
013658,000180:
013659,000181: # THIS ENTRY TO RRNB REQUIRES THE TRUNNION AND SHAFT ANGLES IN MPAC AND MPAC +1 RESPECTIVELY
013660,000182:
013661,000183: 23,2065 14025 RRNBMPAC STODL 20D # SAVE SHAFT CDU IN 21.
013662,000184: 23,2066 00155 MPAC # SET MODE TO DP. (THE PRECEEDING STORE
013663,000185: # MAY BE DP, TP OR VECTOR.)
013664,000186: 23,2067 40234 RTB SETPD
013665,000187: 23,2070 21577 CDULOGIC
013666,000188: 23,2071 00001 0
013667,000189: 23,2072 73406 PUSH SIN # TRUNNION ANGLE TO 0
013668,000190: 23,2073 77676 DCOMP
013669,000191: 23,2074 14043 STODL 34D # Y COMPONENT
013670,000192: 23,2075 41546 COS PUSH # .5COS(T) TO 0
013671,000193: 23,2076 47135 SLOAD RTB # PICK UP CDU'S.
013672,000194: 23,2077 00026 21D
013673,000195: 23,2100 21577 CDULOGIC
013674,000196: 23,2101 77650 GOTO
013675,000197: 23,2102 46054 RRNB1
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Page 326
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013678,000200:
013679,000201:
End of include-file LEM_GEOMETRY.agc. Parent file is MAIN.agc