Source Code
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These source-code files are part of a reconstructed copy of Comanche 45, the
second release, though not the final mission release, of the Apollo 10
Command Module (CM) Apollo Guidance Computer (AGC) software. Comanche 45 was
preceded by Comanche 44 and followed by Comanche 45/2 (the flown release). The reconstruction
is believed to be exactly accurate, but in the absence of an actual Apollo-era
listing of Comanche 45, some explanation of the reconstruction process is needed
to insure confidence in that accuracy.
The starting point was the source code of Comanche 44 (itself previously accurately
reconstructed). Comanche 44 source code was then modified
by incorporating changes known from contemporary documentation to have been
made between revisions 44 and 45. The now-reconstructed Comanche 45 source code was
verified by assembling it and checking that the assembled code had
the expected known-correct memory-bank checksums.
Note that page numbers in the reconstructed code tend to match those in the Comanche 55, the
most-similar revision of Comanche for which we have access to an actual non-reconstructed hardcopy;
the source code would likely have different page numbers in a contemporary
Comanche 45 listing.
Annotations that were not present in the contemporary source code have been added to the reconstructed
code to justify each change relative to Comanche 44. Here's a guide to the Apollo documentation referenced
in those annotations:
There is also
a detailed commentary about the reconstruction process.
Comments expected to have been present in 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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021451,000002: ## Copyright: Public domain.
021452,000003: ## Filename: R31.agc
021453,000004: ## Purpose: A section of Comanche revision 045.
021454,000005: ## It is part of the reconstructed source code for the
021455,000006: ## second release of the flight software for the Command
021456,000007: ## Module's (CM) Apollo Guidance Computer (AGC) for Apollo 10.
021457,000008: ## The code has been recreated from a copy of Comanche 055. It
021458,000009: ## has been adapted such that the resulting bugger words
021459,000010: ## exactly match those specified for Comanche 45 in NASA drawing
021460,000011: ## 2021153D, which gives relatively high confidence that the
021461,000012: ## reconstruction is correct.
021462,000013: ## Assembler: yaYUL
021463,000014: ## Contact: Ron Burkey <info@sandroid.org>.
021464,000015: ## Website: www.ibiblio.org/apollo/index.html
021465,000016: ## Mod history: 2020-12-06 MAS Created from Comanche 44.
021466,000017:
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Page 505
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021468,000019: 34,2002 BANK 34
021469,000020: 31,2000 SETLOC R31
021470,000021: 31,2000 BANK
021471,000022:
021472,000023: 31,2000 COUNT* $$/R31
021473,000024:
021474,000025: 31,2000 35057 R31CALL CAF PRIO3
021475,000026: 31,2001 05147 TC FINDVAC
021476,000027: 31,2002 E4,1770 EBANK= SUBEXIT
021477,000028: 31,2002 02032 62064 2CADR V83CALL
021478,000029:
021479,000030: 31,2004 35041 DSPDELAY CAF 1SEC
021480,000031: 31,2005 04662 TC BANKCALL
021481,000032: 31,2006 01732 CADR DELAYJOB
021482,000033: 31,2007 31044 CA EXTVBACT
021483,000034: 31,2010 75004 MASK BIT12
021484,000035: 31,2011 00006 EXTEND
021485,000036: 31,2012 12004 BZF DSPDELAY
021486,000037:
021487,000038: 31,2013 30105 DISPN5X CA FLAGWRD9 # TEST R31FLAG (IN SUNDANCE R31FLAG WILL
021488,000039: 31,2014 75014 MASK BIT4 # ALWAYS BE SET AS R34 DOES NOT EXIST)
021489,000040: 31,2015 00006 EXTEND
021490,000041: 31,2016 12021 BZF +3
021491,000042: 31,2017 32136 CAF V16N54 # R31 USE NOUN 54
021492,000043: 31,2020 02022 TC +2
021493,000044: 31,2021 32137 CAF V16N53 # R34 USE NOUN 53
021494,000045: 31,2022 04662 TC BANKCALL
021495,000046: 31,2023 20561 CADR GOMARKF
021496,000047: 31,2024 05625 TC B5OFF
021497,000048: 31,2025 05625 TC B5OFF
021498,000049: 31,2026 12013 TCF DISPN5X
021499,000050:
021500,000051: 31,2027 06006 V83 TC INTPRET
021501,000052: 31,2030 77650 GOTO
021502,000053: 31,2031 62171 HAVEBASE # INTEG STATE VECTORS
021503,000054: 31,2032 06006 V83CALL TC INTPRET
021504,000055: 31,2033 77650 GOTO
021505,000056: 31,2034 62140 STATEXTP # EXTRAPOLATE STATE VECTORS
021506,000057: 31,2035 52375 COMPDISP VLOAD VSU
021507,000058: 31,2036 00001 RATT
021508,000059: 31,2037 02327 RONE
021509,000060: 31,2040 51406 PUSH ABVAL # RATT-RONE TO 0D PD= 6
021510,000061: 31,2041 02321 STORE RANGE # METERS B-29
021511,000062: 31,2042 77301 NORM VLOAD
021512,000063: 31,2043 00047 X1 # RATT-RONE PD= 0
021513,000064: 31,2044 77762 VSR1
021514,000065: 31,2045 53457 VSL* UNIT
021515,000066: 31,2046 20201 0,1
021516,000067: 31,2047 52315 PDVL VSU # UNIT(LOS) TO 0D PD= 6
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Page 506
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021518,000069: 31,2050 00007 VATT
021519,000070: 31,2051 02335 VONE
021520,000071: 31,2052 77641 DOT # (VATT-VONE).UNIT(LOS) PD= 0
021521,000072: 31,2053 77752 SL1
021522,000073: 31,2054 36323 STCALL RRATE # RANGE RATE M/CS B-7
021523,000074: 31,2055 47477 CDUTRIG # TO INITIALIZE FOR *NBSM*
021524,000075: 31,2056 77624 CALL
021525,000076: 31,2057 62311 R34LOS # NOTE. PDL MUST = 0.
021526,000077: 31,2060 53575 R34ANG VLOAD UNIT
021527,000078: 31,2061 02327 RONE
021528,000079: 31,2062 77715 PDVL # UR TO 0D PD= 6
021529,000080: 31,2063 15333 THISAXIS # UNITX FOR CM, UNITZ FOR LM
021530,000081: 31,2064 77214 BON VLOAD # CHK R31FLAG. ON=R31 THETA, OFF=R34 PHI
021531,000082: 31,2065 04713 R31FLAG
021532,000083: 31,2066 62070 +2 # R31-THETA
021533,000084: 31,2067 00015 12D
021534,000085: 31,2070 77624 CALL
021535,000086: 31,2071 47646 *NBSM*
021536,000087: 31,2072 41505 VXM PUSH # UXORZ TO 6D PD=12D
021537,000088: 31,2073 01736 REFSMMAT
021538,000089: 31,2074 72431 VPROJ VSL2
021539,000090: 31,2075 00001 0D
021540,000091: 31,2076 53445 BVSU UNIT
021541,000092: 31,2077 00007 6D
021542,000093: 31,2100 47315 PDVL VXV # UP/2 TO 12D PD=18D
021543,000094: 31,2101 02327 RONE
021544,000095: 31,2102 02335 VONE
021545,000096: 31,2103 47256 UNIT VXV
021546,000097: 31,2104 02327 RONE
021547,000098: 31,2105 63241 DOT PDVL # SIGN TO 12D, UP/2 TO MPAC PD=18D
021548,000099: 31,2106 00015 12D
021549,000100: 31,2107 50372 VSL1 DOT # UP.UXORZ
021550,000101: 31,2110 00007 6D
021551,000102: 31,2111 72565 SIGN SL1
021552,000103: 31,2112 00015 12D
021553,000104: 31,2113 77726 ACOS
021554,000105: 31,2114 26325 STOVL RTHETA
021555,000106: 31,2115 02327 RONE
021556,000107: 31,2116 51041 DOT BPL
021557,000108: 31,2117 00007 6D
021558,000109: 31,2120 62125 +5
021559,000110: 31,2121 44345 DLOAD BDSU # IF UXORZ.R NEG, RTHETA = 1 - RTHETA
021560,000111: 31,2122 02325 RTHETA
021561,000112: 31,2123 15343 DPPOSMAX
021562,000113: 31,2124 02325 STORE RTHETA # RTHETA BETWEEN 0 AND 1 REV.
021563,000114: 31,2125 77776 EXIT
021564,000115: 31,2126 35013 CAF BIT5 # HAVE WE BEEN ANSWERED
021565,000116: 31,2127 71044 MASK EXTVBACT
021566,000117: 31,2130 00006 EXTEND
021567,000118: 31,2131 15534 BZF ENDEXT # YES, DIE
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Page 507
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021569,000120: 31,2132 41044 CS EXTVBACT
021570,000121: 31,2133 75004 MASK BIT12
021571,000122: 31,2134 27044 ADS EXTVBACT
021572,000123:
021573,000124: 31,2135 12027 TCF V83
021574,000125: 31,2136 04066 V16N54 VN 1654
021575,000126: 31,2137 04065 V16N53 VN 1653
021576,000127:
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Page 508
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021578,000129: # STATEXTP DOES AN INITIAL PRECISION EXTRAPOLATION OF THE
021579,000130: # LEM STATE VECTOR TO PRESENT TIME OR TO PIPTIME IF AV G
021580,000131: # IS ON AND SAVES AS BASE VECTOR. IF AV G IS ON RN + VN
021581,000132: # ARE USED AS THE CM STATE VECTOR AND THE INITIAL R RDOT
021582,000133: # RTHETA ARE COMPUTED WITH NO FURTHER INTEGRATION. IF AV
021583,000134: # G IS OFF A PRECISION EXTRAPOLATION IS MADE OF THE CM
021584,000135: # STATE VECTOR TO PRESENT TIME AND.....
021585,000136:
021586,000137: # THE CM + LM STATE VECTORS ARE INTEGRATED TO PRES TIME
021587,000138: # USING PRECISION OR CONIC AS SURFFLAG IS SET OR CLEAR.
021588,000139:
021589,000140: # IF AV G IS ON THEN SUBSEQUENT PASSES WILL PROVIDE
021590,000141: # USE OF RN + VN AS CM STATE VECTOR AND THE LM STATE
021591,000142: # VECTOR WILL BE PRECISION INTEGRATED USING LEMPREC
021592,000143:
021593,000144: # IF SURFFLAG IS SET.
021594,000145: # CM STATE VECTOR RONE VONE + LM STATE VECTOR RATT
021595,000146: # VATT ARE USED IN COMPUTING R RDOT RTHETA.
021596,000147:
021597,000148:
021598,000149: 31,2140 43034 STATEXTP RTB BOF # INITIAL INTEGRATION
021599,000150: 31,2141 45510 LOADTIME
021600,000151: 31,2142 03751 V37FLAG
021601,000152: 31,2143 62146 +3 # AV G OFF, USE PRES TIME
021602,000153: 31,2144 77624 CALL
021603,000154: 31,2145 62273 GETRVN # ON, USE RN VN PIPTIME
021604,000155: 31,2146 02343 STORE BASETIME # PRES TIME OR PIPTIME
021605,000156: 31,2147 34041 STCALL TDEC1
021606,000157: 31,2150 27105 LEMPREC
021607,000158: 31,2151 77775 VLOAD # BASE VECTOR, LM
021608,000159: 31,2152 00017 RATT1
021609,000160: 31,2153 26225 STOVL BASEOTP # POS.
021610,000161: 31,2154 00025 VATT1
021611,000162: 31,2155 02241 STORE BASEOTV # VEL.
021612,000163: 31,2156 71214 BON DLOAD
021613,000164: 31,2157 03711 V37FLAG
021614,000165: 31,2160 62035 COMPDISP # COMPUTE R RDOT RTHETA FROM
021615,000166: # RONE(RN) VONE(VN) RATT+VATT(LEMPREC)
021616,000167: 31,2161 00015 TAT
021617,000168: 31,2162 34041 STCALL TDEC1
021618,000169: 31,2163 27071 CSMPREC
021619,000170: 31,2164 77775 VLOAD # BASE VECTOR, CM
021620,000171: 31,2165 00017 RATT1
021621,000172: 31,2166 26255 STOVL BASETHP # POS.
021622,000173: 31,2167 00025 VATT1
021623,000174: 31,2170 02263 STORE BASETHV # VEL.
021624,000175: 31,2171 47014 HAVEBASE BON RTB # SUBSEQUENT INTEGRATIONS
021625,000176: 31,2172 03711 V37FLAG
021626,000177: 31,2173 62256 GETRVN5
021627,000178: 31,2174 45510 LOADTIME
021628,000179: 31,2175 34041 STCALL TDEC1 # AV G OFF. SET INTEG. OF CM
021629,000180: 31,2176 27442 INTSTALL
021630,000181: 31,2177 43175 VLOAD CLEAR
021631,000182: 31,2200 02255 BASETHP
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Page 509
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021633,000184: 31,2201 00263 MOONFLAG
021634,000185: 31,2202 25535 STOVL RCV
021635,000186: 31,2203 02263 BASETHV
021636,000187: 31,2204 15543 STODL VCV
021637,000188: 31,2205 02343 BASETIME
021638,000189: 31,2206 43014 BOF SET # GET APPROPRIATE MOONFLAG SETTING
021639,000190: 31,2207 04343 MOONTHIS
021640,000191: 31,2210 62212 +2
021641,000192: 31,2211 00063 MOONFLAG
021642,000193: 31,2212 77614 CLEAR
021643,000194: 31,2213 01673 INTYPFLG
021644,000195: 31,2214 43014 BON SET
021645,000196: 31,2215 04307 SURFFLAG
021646,000197: 31,2216 62220 +2 # PREC. IF LM DOWN
021647,000198: 31,2217 01473 INTYPFLG # CONIC IF LM NOT DOWN
021648,000199: 31,2220 35517 STCALL TET
021649,000200: 31,2221 27135 INTEGRVS # INTEGRATION --- AT LAST---
021650,000201: 31,2222 77775 VLOAD
021651,000202: 31,2223 00001 RATT
021652,000203: 31,2224 26327 STOVL RONE
021653,000204: 31,2225 00007 VATT
021654,000205: 31,2226 16335 STODL VONE # GET SET FOR CONIC EXTRAP.,OTHER
021655,000206: 31,2227 00015 TAT
021656,000207: 31,2230 45014 BON CALL
021657,000208: 31,2231 04307 SURFFLAG
021658,000209: 31,2232 62267 GETRVN6 # LEMPREC IF LM DOWN
021659,000210: 31,2233 27442 INTSTALL # ..CONIC IF NOT DOWN
021660,000211: 31,2234 77614 SET
021661,000212: 31,2235 01473 INTYPFLG
021662,000213: 31,2236 00041 OTHINT STORE TDEC1 # ENTERED IF AV G ON TO INTEG LM
021663,000214: 31,2237 43175 VLOAD CLEAR
021664,000215: 31,2240 02225 BASEOTP
021665,000216: 31,2241 00263 MOONFLAG
021666,000217: 31,2242 25535 STOVL RCV
021667,000218: 31,2243 02241 BASEOTV
021668,000219: 31,2244 15543 STODL VCV
021669,000220: 31,2245 02343 BASETIME
021670,000221: 31,2246 43014 BOF SET
021671,000222: 31,2247 04343 MOONTHIS
021672,000223: 31,2250 62252 +2
021673,000224: 31,2251 00063 MOONFLAG
021674,000225: 31,2252 35517 STCALL TET
021675,000226: 31,2253 27135 INTEGRVS
021676,000227: 31,2254 77650 GOTO
021677,000228: 31,2255 62035 COMPDISP # COMPUTE R RDOT RTHETA
021678,000229: 31,2256 77624 GETRVN5 CALL # AV G ON
021679,000230: 31,2257 62273 GETRVN
021680,000231: 31,2260 45014 BON CALL
021681,000232: 31,2261 04307 SURFFLAG
021682,000233: 31,2262 62267 GETRVN6 # LM DOWN, LMPREC
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Page 510
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021684,000235: 31,2263 27442 INTSTALL
021685,000236: 31,2264 52014 CLEAR GOTO
021686,000237: 31,2265 01673 INTYPFLG
021687,000238: 31,2266 62236 OTHINT
021688,000239: 31,2267 34041 GETRVN6 STCALL TDEC1
021689,000240: 31,2270 27105 LEMPREC
021690,000241: 31,2271 77650 GOTO
021691,000242: 31,2272 62035 COMPDISP # COMPUTE R RDOT RTHETA
021692,000243: 31,2273 77620 GETRVN STQ
021693,000244: 31,2274 00000 0D
021694,000245: 31,2275 52175 VLOAD GOTO # AV G ON, RONE = RN VONE = VN
021695,000246: 31,2276 01171 RN # AND USE PIPTIME
021696,000247: 31,2277 62300 +1
021697,000248: 31,2300 36327 STCALL RONE
021698,000249: 31,2301 62302 +1
021699,000250: 31,2302 52175 VLOAD GOTO
021700,000251: 31,2303 01177 VN
021701,000252: 31,2304 62305 +1
021702,000253: 31,2305 16335 STODL VONE
021703,000254: 31,2306 01205 PIPTIME
021704,000255: 31,2307 77650 GOTO
021705,000256: 31,2310 00000 0D
021706,000257: 31,2000 SETLOC R34
021707,000258: 31,2000 BANK
021708,000259: 31,2311 77776 R34LOS EXIT
021709,000260: 31,2312 30036 CA CDUS
021710,000261: 31,2313 50120 INDEX FIXLOC
021711,000262: 31,2314 54011 TS 9D
021712,000263: 31,2315 30035 CA CDUT
021713,000264: 31,2316 50120 INDEX FIXLOC
021714,000265: 31,2317 54013 TS 11D
021715,000266: 31,2320 30120 CA FIXLOC
021716,000267: 31,2321 66211 AD SIX
021717,000268: 31,2322 40000 COM
021718,000269: 31,2323 50120 INDEX FIXLOC
021719,000270: 31,2324 54046 TS X1
021720,000271: 31,2325 06006 TC INTPRET
021721,000272: 31,2326 77624 CALL
021722,000273: 31,2327 46000 SXTNB
021723,000274: 31,2330 34015 STCALL 12D
021724,000275: 31,2331 62060 R34ANG
End of include-file R31.agc. Parent file is MAIN.agc