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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021727,000002: ## Copyright: Public domain.
021728,000003: ## Filename: P76.agc
021729,000004: ## Purpose: A section of Comanche revision 045.
021730,000005: ## It is part of the reconstructed source code for the
021731,000006: ## second release of the flight software for the Command
021732,000007: ## Module's (CM) Apollo Guidance Computer (AGC) for Apollo 10.
021733,000008: ## The code has been recreated from a copy of Comanche 055. It
021734,000009: ## has been adapted such that the resulting bugger words
021735,000010: ## exactly match those specified for Comanche 45 in NASA drawing
021736,000011: ## 2021153D, which gives relatively high confidence that the
021737,000012: ## reconstruction is correct.
021738,000013: ## Assembler: yaYUL
021739,000014: ## Contact: Ron Burkey <info@sandroid.org>.
021740,000015: ## Website: www.ibiblio.org/apollo/index.html
021741,000016: ## Mod history: 2020-12-06 MAS Created from Comanche 44.
021742,000017:
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Page 511
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021744,000019: # 1) PROGRAM NAME - TARGET DELTA V PROGRAM (P76).
021745,000020: # 2) FUNCTIONAL DESCRIPTION - UPON ENTRY BY ASTRONAUT ACTION, P76 FLASHES DSKY REQUESTS TO THE ASTRONAUT
021746,000021: # TO PROVIDE VIA DSKY (1) THE DELTA V TO BE APPLIED TO THE OTHER VEHICLE STATE VECTOR AND (2) THE
021747,000022: # TIME (TIG) AT WHICH THE OTHER VEHICLE VELOCITY WAS CHANGED BY EXECUTION OF A THRUSTING MANEUVER. THE
021748,000023: # OTHER VEHICLE STATE VECTOR IS INTEGRATED TO TIG AND UPDATED BY THE ADDITION OF DELTA V (DELTA V HAVING
021749,000024: # BEEN TRANSFORMED FROM LV TO REF COSYS). USING INTEGRVS, THE PROGRAM THEN INTEGRATES THE OTHER
021750,000025: # VEHICLE STATE VECTOR TO THE STATE VECTOR OF THIS VEHICLE, THUS INSURING THAT THE W-MATRIX AND BOTH VEHICLE
021751,000026: # STATES CORRESPOND TO THE SAME TIME.
021752,000027: # 3) ERASABLE INITIALIZATION REQUIRED - NONE.
021753,000028: # 4) CALLING SEQUENCES AND EXIT MODES - CALLED BY ASTRONAUT REQUEST THRU DSKY V 37 E 76E.
021754,000029: # EXITS BY TCF ENDOFJOB.
021755,000030: # 5) OUTPUT - OTHER VEHICLE STATE VECTOR INTEGRATED TO TIG AND INCREMENTED BY DELTA V IN REF COSYS.
021756,000031: # THE PUSHLIST CONTAINS THE MATRIX BY WHICH THE INPUT DELTA V MUST BE POST-MULTIPLIED TO CONVERT FROM LV
021757,000032: # TO REF COSYS.
021758,000033: # 6) DEBRIS - OTHER VEHICLE STATE VECTOR.
021759,000034: # 7) SUBROUTINES CALLED - BANKCALL, GOXDSPF, CSMPREC (OR LEMPREC), ATOPCSM (OR ATOPLEM), INTSTALL, INTWAKE, PHASCHNG
021760,000035: # INTPRET, INTEGRVS, AND MINIRECT.
021761,000036: # 8) FLAG USE - MOONFLAG, CMOONFLAG, INTYPFLG, RASFLAG, AND MARKCTR.
021762,000037:
021763,000038: 30,2000 BANK 30
021764,000039: 13,2000 SETLOC P76LOC
021765,000040: 13,2000 BANK
021766,000041:
021767,000042: 13,2071 COUNT* $$/P76
021768,000043:
021769,000044: 13,2071 E7,1412 EBANK= TIG
021770,000045:
021771,000046: 13,2071 05546 P76 TC UPFLAG
021772,000047: 13,2072 00031 ADRES TRACKFLG
021773,000048:
021774,000049: 13,2073 32220 CAF V06N84 # FLASH LAST DELTA V,
021775,000050: 13,2074 04662 TC BANKCALL # AND WAIT FOR KEYBOARD ACTION.
021776,000051: 13,2075 20720 CADR GOFLASH
021777,000052: 13,2076 12212 TCF ENDP76
021778,000053: 13,2077 02101 TC +2 # PROCEED
021779,000054: 13,2100 02073 TC -5 # STORE DATA AND REPEAT FLASHING
021780,000055: 13,2101 32221 CAF V06N84 +1 # FLASH VERB 06 NOUN 33, DISPLAY LAST TIG,
021781,000056: 13,2102 04662 TC BANKCALL # AND WAIT FOR KEYBOARD ACTION.
021782,000057: 13,2103 20720 CADR GOFLASH
021783,000058: 13,2104 12212 TCF ENDP76
021784,000059: 13,2105 02107 TC +2
021785,000060: 13,2106 02101 TC -5
021786,000061: 13,2107 06006 TC INTPRET # RETURN TO INTERPRETIVE CODE
021787,000062: 13,2110 77745 DLOAD # SET D(MPAC)=TIG IN CSEC B28
021788,000063: 13,2111 03413 TIG
021789,000064: 13,2112 34041 STCALL TDEC1 # SET TDEC1=TIG FOR ORBITAL INTEGRATION
021790,000065: 13,2113 27105 OTHPREC
021791,000066: 13,2114 53575 COMPMAT VLOAD UNIT
021792,000067: 13,2115 00001 RATT
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Page 512
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021794,000069: 13,2116 77676 VCOMP # U(-R)
021795,000070: 13,2117 00031 STORE 24D # U(-R) TO 24D
021796,000071: 13,2120 53435 VXV UNIT # U(-R) X V = U(V X R)
021797,000072: 13,2121 00007 VATT
021798,000073: 13,2122 00023 STORE 18D
021799,000074: 13,2123 53435 VXV UNIT # U(V X R) X U(-R) = U((R X V) X R)
021800,000075: 13,2124 00031 24D
021801,000076: 13,2125 24015 STOVL 12D
021802,000077: 13,2126 03540 DELVOV
021803,000078: 13,2127 76505 VXM VSL1 # V(MPAC)=DELTA V IN REFCOSYS
021804,000079: 13,2130 00015 12D
021805,000080: 13,2131 77655 VAD
021806,000081: 13,2132 00007 VATT
021807,000082: 13,2133 00007 STORE 6 # V(PD6)=VATT + DELTA V
021808,000083: 13,2134 77624 CALL # PREVENT WOULD-BE USER OF ORBITAL
021809,000084: 13,2135 27442 INTSTALL # INTEG FROM INTERFERING WITH UPDATING
021810,000085: 13,2136 77624 CALL
021811,000086: 13,2137 26222 P76SUB1
021812,000087: 13,2140 53775 VLOAD VSR*
021813,000088: 13,2141 00007 6
021814,000089: 13,2142 57176 0,2
021815,000090: 13,2143 25543 STOVL VCV
021816,000091: 13,2144 00001 RATT
021817,000092: 13,2145 77657 VSR*
021818,000093: 13,2146 57176 0,2
021819,000094: 13,2147 15535 STODL RCV
021820,000095: 13,2150 03413 TIG
021821,000096: 13,2151 01517 STORE TET
021822,000097: 13,2152 71214 CLEAR DLOAD
021823,000098: 13,2153 01673 INTYPFLG
021824,000099: 13,2154 01571 TETTHIS
021825,000100: 13,2155 34041 INTOTHIS STCALL TDEC1
021826,000101: 13,2156 27135 INTEGRVS
021827,000102: 13,2157 77624 CALL
021828,000103: 13,2160 27442 INTSTALL
021829,000104: 13,2161 77624 CALL
021830,000105: 13,2162 26222 P76SUB1 # SET/CLEAR MOONFLAG
021831,000106: 13,2163 77775 VLOAD
021832,000107: 13,2164 00017 RATT1
021833,000108: 13,2165 01503 STORE RRECT
021834,000109: 13,2166 15535 STODL RCV
021835,000110: 13,2167 00015 TAT
021836,000111: 13,2170 25517 STOVL TET
021837,000112: 13,2171 00025 VATT1
021838,000113: 13,2172 77624 CALL
021839,000114: 13,2173 23435 MINIRECT
021840,000115: 13,2174 77776 EXIT
021841,000116: 13,2175 05412 TC PHASCHNG
021842,000117: 13,2176 04024 OCT 04024
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Page 513
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021844,000119: 13,2177 05546 TC UPFLAG
021845,000120: 13,2200 00236 ADRES REINTFLG
021846,000121:
021847,000122: 13,2201 06006 TC INTPRET
021848,000123: 13,2202 77624 CALL
021849,000124: 13,2203 26760 ATOPOTH
021850,000125: 13,2204 77531 SSP EXIT
021851,000126: 13,2205 00053 QPRET
021852,000127: 13,2206 26211 OUT
021853,000128: 13,2207 04662 TC BANKCALL # PERMIT USE OF ORBITAL INTEGRATION
021854,000129: 13,2210 27477 CADR INTWAKE1
021855,000130: 13,2211 77776 OUT EXIT
021856,000131: 13,2212 35021 ENDP76 CAF ZERO
021857,000132: 13,2213 55126 TS MARKCTR # CLEAR RR TRACKING MARK COUNTER
021858,000133: 13,2214 55125 TS VHFCNT
021859,000134:
021860,000135: 13,2215 37716 CAF NEGONE
021861,000136: 13,2216 55734 TS MRKBUF2 # INVALIDATE MARK BUFFER
021862,000137:
021863,000138: 13,2217 14106 TCF GOTOPOOH
021864,000139:
021865,000140: 13,2220 01524 V06N84 NV 0684
021866,000141: 13,2221 01441 NV 0633
021867,000142: 13,2222 67214 P76SUB1 CLEAR SLOAD
021868,000143: 13,2223 00263 MOONFLAG
021869,000144: 13,2224 00050 X2
021870,000145: 13,2225 43030 BHIZ SET # X2=0...CLEAR MOONFLAG
021871,000146: 13,2226 26230 +2 # =2.....SET MOONFLAG
021872,000147: 13,2227 00063 MOONFLAG
021873,000148: 13,2230 77616 RVQ
021874,000149:
End of include-file P76.agc. Parent file is MAIN.agc