Source Code
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These source-code files are part of a reconstructed copy of Luminary 69/2,
the flown, final release of the Apollo 10 Lunar Module (LM) Apollo Guidance Computer (AGC) software.
The reconstruction is based on the source code of Luminary 69 — i.e., the
initial, unflown version, "revision 0" — of which
a contemporary listing was available. The code was then updated by incorporating the
differences between Luminary 69 and Luminary 69/2, known from other contemporary
documentation. The only such difference is the implementation in
Luminary 69/2 of the "R-2 Lunar Potential Model", the source code for which was taken
from program Luminary 99/1 (Apollo 11 LM), of which a contemporary listing was also available.
Finally, the now-reconstructed Luminary 69/2 was then validated by assembling it to
executable form and verifying that its memory banks had the correct checksums,
known from still other contemporary documentation.
Note that page numbers in the reconstructed code match those in the original Luminary 69
program listing, or in the ORBITAL INTEGRATION log section, in Luminary 99/1. Page numbers
would certainly differ somewhat in a contemporary Luminary 69/2 listing.
Moreover, annotations that were not present in the contemporary source code have been added
to the reconstructed code to justify each change in Luminary 69/2 relative to
Luminary 69. Here's a guide to the Apollo documentation referenced in those annotations:
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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009533,000002: ## Copyright: Public domain.
009534,000003: ## Filename: AGS_INITIALIZATION.agc
009535,000004: ## Purpose: A section of LUM69 revision 2.
009536,000005: ## It is part of the reconstructed source code for the flown
009537,000006: ## version of the flight software for the Lunar Module's (LM)
009538,000007: ## Apollo Guidance Computer (AGC) for Apollo 10. The code has
009539,000008: ## been recreated from a copy of Luminary revsion 069, using
009540,000009: ## changes present in Luminary 099 which were described in
009541,000010: ## Luminary memos 75 and 78. The code has been adapted such
009542,000011: ## that the resulting bugger words exactly match those specified
009543,000012: ## for LUM69 revision 2 in NASA drawing 2021152B, which gives
009544,000013: ## relatively high confidence that the reconstruction is correct.
009545,000014: ## Reference: pp. 221-225
009546,000015: ## Assembler: yaYUL
009547,000016: ## Contact: Ron Burkey <info@sandroid.org>.
009548,000017: ## Website: www.ibiblio.org/apollo/index.html
009549,000018: ## Mod history: 2019-07-27 MAS Created from Luminary 69.
009550,000019:
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Page 221
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009552,000021:
009553,000022: # PROGRAM NAME: AGS INITIALIZATION (R47)
009554,000023:
009555,000024: # WRITTEN BY : RHODE/KILROY/FOLLETT
009556,000025:
009557,000026: # MOD NO. : 0
009558,000027: # DATE : 23 MARCH 1967
009559,000028: # MOD BY : KILROY
009560,000029:
009561,000030: # MOD NO. : 1
009562,000031: # DATE : 28 OCTOBER 1967
009563,000032: # MOD BY : FOLLETT
009564,000033:
009565,000034: # FUNCT. DESC.: (1) TO PROVIDE THE AGS ABORT ELECTRONICS ASSEMBLY(AEA) WITH THE LEM AND CSM STATE VECTORS
009566,000035: # (POSITION,VELOCITY,TIME) IN LEM IMU COORDINATES BY MEANS OF THE LGC DIGITAL DOWNLINK.
009567,000036:
009568,000037: # (2) TO ZERO THE ICDU, LGC AND AEA GIMBAL ANGLE COUNTERS SIMULTANEOUSLY IN ORDER TO ESTABLISH A
009569,000038: # COMMON ZERO REFERENCE FOR THE MEASUREMENT OF GIMBAL(EULER) ANGLES WHICH DEFINE LEM ATTITUDE
009570,000039: # (3) TO ESTABLISH THE GROUND ELAPSED TIME OF AEA CLOCK ZERO.(IF AN AEA CLOCK ZERO IS
009571,000040: # REQUESTED DURING THIS PROGRAM
009572,000041:
009573,000042: # LOG SECTION : AGS INITIALIZATION
009574,000043:
009575,000044: # CALLING SEQ : PROGRAM IS ENTERED WHEN ASTRONAUT KEYS V47E ON DSKY.
009576,000045: # R47 MAY BE CALLED AT ANY TIME EXCEPT WHEN ANOTHER EXTENDED VERB IS IN PROGRESS
009577,000046:
009578,000047: # SUBROUTINES
009579,000048: # CALLED :
009580,000049:
009581,000050: # NORMAL EXIT : ENDEXT
009582,000051:
009583,000052: # ALARM/ABORT : ALARM - BAD REFSMMAT - CODE:220
009584,000053: # OPERATOR ERROR IF V47 SELECTED DURING ANOTHER EXTENDED VERB.
009585,000054:
009586,000055: # ERASABLES
009587,000056: # USED : SAMPTIME (2) TIME OF :ENTER: KEYSTROKE
009588,000057: # AGSK (2) GROUND ELAPSED TIME OF THE AEA CLOCK :ZERO:
009589,000058: # AGSBUFF (140) CONTAINS AGS INITIALIZATION DATA (SEE :OUTPUT: BELOW)
009590,000059: # AGSWORD (1) PREVIOUS DOWNLIST SAVED HERE
009591,000060:
009592,000061: 05,2447 E4,1604 EBANK= AGSBUFF
009593,000062:
009594,000063: 40,2000 BANK 40
009595,000064: 32,2000 SETLOC R47
009596,000065: 32,2000 BANK
009597,000066:
009598,000067: 32,2015 COUNT* $$/R47
009599,000068:
009600,000069: 32,2015 34737 AGSINIT CAF REFSMBIT
009601,000070: 32,2016 70077 MASK FLAGWRD3 # CHECK REFSMFLG.
009602,000071: 32,2017 10000 CCS A
009603,000072:
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Page 222
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009605,000074: 32,2020 02027 TC REDSPTEM # REFSMMAT IS OK
009606,000075: 32,2021 05567 TC ALARM # REFSMMAT IS BAD
009607,000076: 32,2022 00220 OCT 220
009608,000077: 32,2023 05472 TC ENDEXT
009609,000078:
009610,000079: 32,2024 00006 NEWAGS EXTEND
009611,000080: 32,2025 30014 DCA SAMPTIME # TIME OF THE :ENTER: KEYSTROKE
009612,000081: 32,2026 53421 DXCH AGSK # BECOMES NEW AEA CLOCK :ZERO:
009613,000082:
009614,000083: 32,2027 00006 REDSPTEM EXTEND
009615,000084: 32,2030 31421 DCA AGSK
009616,000085: 32,2031 53052 DXCH DSPTEMX
009617,000086: 32,2032 32202 AGSDISPK CAF V06N16
009618,000087: 32,2033 04616 TC BANKCALL # R1 = 00XXX. HRS., R2 = 000XX MIN.,
009619,000088: 32,2034 20212 CADR GOMARKF # R3 = 0XX.XX SEC.
009620,000089: 32,2035 05472 TC ENDEXT # TERMINATE RETURN
009621,000090: 32,2036 02046 TC AGSVCALC # PROCEED RETURN
009622,000091: 32,2037 44746 CS BIT6 # IS ENTER VIA A V32
009623,000092: 32,2040 60154 AD MPAC
009624,000093: 32,2041 00006 EXTEND
009625,000094: 32,2042 12024 BZF NEWAGS # YES, USE KEYSTROKE TIME FOR NEW AGSK
009626,000095:
009627,000096: 32,2043 00006 EXTEND # NO, NEW AGSK LOADED VIA V25
009628,000097: 32,2044 31052 DCA DSPTEMX # LOADED INTO DSPTEMX BY KEYING
009629,000098: 32,2045 02026 TC REDSPTEM -1 # V25E FOLLOWED BY HRS.,MINS.,SECS.
009630,000099: # DISPLAY THE NEW K
009631,000100:
009632,000101: 32,2046 06036 AGSVCALC TC INTPRET
009633,000102: 32,2047 77614 SET
009634,000103: 32,2050 01076 NODOFLAG # DONT ALLOW V37
009635,000104: 32,2051 77414 SET EXIT
009636,000105: 32,2052 02076 XDSPFLAG
009637,000106:
009638,000107: 32,2053 32202 CAF V06N16
009639,000108: 32,2054 04616 TC BANKCALL
009640,000109: 32,2055 20473 CADR EXDSPRET
009641,000110:
009642,000111: 32,2056 06036 TC INTPRET # EXTRAPOLATE LEM AND CSM STATE VECTORS
009643,000112: 32,2057 77634 RTB # TO THE PRESENT TIME
009644,000113: 32,2060 21462 LOADTIME # LOAD MPAC WITH TIME2,TIME1
009645,000114: 32,2061 34041 STCALL TDEC1 # CALCULATE LEM STATE VECTOR
009646,000115: 32,2062 27057 LEMPREC
009647,000116: 32,2063 77624 CALL # CALL ROUTINE TO CONVERT TO SM COORDS AND
009648,000117: 32,2064 64142 SCALEVEC # PROVIDE PROPER SCALING
009649,000118: 32,2065 16205 STODL AGSBUFF # (LEMPREC AND CSMPREC LEAVE TDEC1 IN TAT)
009650,000119: 32,2066 00015 TAT # TAT = TIME TO WHICH RATT1 AND VATT1 ARE
009651,000120: 32,2067 34041 STCALL TDEC1 # COMPUTED(CSEC SINCE CLOCK START B-28).
009652,000121: 32,2070 27043 CSMPREC # CALCULATE CSM STATE VECTOR FOR SAME TIME
009653,000122: 32,2071 77624 CALL
009654,000123: 32,2072 64142 SCALEVEC
009655,000124:
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009657,000126: 32,2073 16213 STODL AGSBUFF +6
009658,000127: 32,2074 00015 TAT
009659,000128: 32,2075 56225 DSU DDV # CALCULATE AND STORE THE TIME
009660,000129: 32,2076 02021 AGSK
009661,000130: 32,2077 24205 TSCALE
009662,000131: 32,2100 02221 STORE AGSBUFF +12D
009663,000132: 32,2101 77776 EXIT
009664,000133:
009665,000134: 32,2102 34753 CAF LAGSLIST
009666,000135: 32,2103 54332 TS DNLSTCOD
009667,000136:
009668,000137: 32,2104 32206 CAF 20SEC # DELAY FOR 20 SEC WHILE THE AGS
009669,000138: 32,2105 04616 TC BANKCALL # DOWNLIST IS TRANSMITTED
009670,000139: 32,2106 01735 CADR DELAYJOB
009671,000140:
009672,000141: 32,2107 31324 CA AGSWORD
009673,000142: 32,2110 54332 TS DNLSTCOD # RETURN TO THE OLD DOWNLIST
009674,000143: 32,2111 34744 CAF IMUSEBIT
009675,000144: 32,2112 70074 MASK FLAGWRD0 # CHECK IMUSE FLAG.
009676,000145: 32,2113 10000 CCS A
009677,000146: 32,2114 02132 TC AGSEND # IMU IS BEING USED - DO NOT ZERO
009678,000147: 32,2115 11304 CKSTALL CCS IMUCADR # CHECK FOR IMU USAGE WHICH AVOIDS THE
009679,000148: 32,2116 12121 TCF +3 # IMUSE BIT: I.E., IMU COMPENSATION.
009680,000149: 32,2117 12125 TCF +6 # FREE. GO AHEAD WITH THE IMU ZERO.
009681,000150: 32,2120 12121 TCF +1
009682,000151: 32,2121 34363 +3 CAF TEN # WAIT .1 SEC AND TRY AGAIN.
009683,000152: 32,2122 04616 TC BANKCALL
009684,000153: 32,2123 01735 CADR DELAYJOB
009685,000154: 32,2124 12115 TCF CKSTALL
009686,000155:
009687,000156: 32,2125 04616 +6 TC BANKCALL # IMU IS NOT IN USE
009688,000157: 32,2126 16667 CADR IMUZERO # SET IMU ZERO DISCRETE FOR 320MSECS
009689,000158: 32,2127 04616 TC BANKCALL # WAIT 3 SEC FOR COUNTERS TO INCREMENT
009690,000159: 32,2130 17671 CADR IMUSTALL
009691,000160: 32,2131 02132 TC AGSEND
009692,000161: 32,2132 05516 AGSEND TC DOWNFLAG # ALLOW V37
009693,000162: 32,2133 00054 ADRES NODOFLAG
009694,000163:
009695,000164: 32,2134 32203 CAF V50N16
009696,000165: 32,2135 04616 TC BANKCALL
009697,000166: 32,2136 20220 CADR GOMARK3
009698,000167: 32,2137 15472 TCF ENDEXT
009699,000168: 32,2140 15472 TCF ENDEXT
009700,000169: 32,2141 05472 TC ENDEXT
009701,000170:
009702,000171: 32,2142 64375 SCALEVEC VLOAD MXV
009703,000172: 32,2143 00025 VATT1
009704,000173: 32,2144 01734 REFSMMAT
009705,000174: 32,2145 72561 VXSC VSL2
009706,000175: 32,2146 24212 VSCALE
009707,000176:
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009709,000178: 32,2147 53255 VAD VAD # THIS SECTION ROUNDS THE VECTOR, AND
009710,000179: 32,2150 24214 AGSRND1 # CORRECTS FOR THE FACT THAT THE AGS
009711,000180: 32,2151 24222 AGSRND2 # IS A 2 S COMPLIMENT MACHINE WHILE THE
009712,000181: 32,2152 77634 RTB # LGC IS A 1 S COMPLIMENT MACHINE.
009713,000182: 32,2153 21744 VECSGNAG
009714,000183: 32,2154 24025 STOVL VATT1
009715,000184: 32,2155 00017 RATT1
009716,000185: 32,2156 74321 MXV VXSC
009717,000186: 32,2157 01734 REFSMMAT
009718,000187: 32,2160 24210 RSCALE
009719,000188: 32,2161 53212 VSL8 VAD # AGAIN THIS SECTION ROUNDS. TWO VECTORS
009720,000189: 32,2162 24214 AGSRND1 # ARE ADDED TO DEFEAT ALSIGNAG IN THE
009721,000190: 32,2163 47055 VAD RTB # CASE OF A HIGH-ORDER ZERO COUPLED WITH
009722,000191: 32,2164 24222 AGSRND2 # A LOW ORDER NEGATIVE PART.
009723,000192: 32,2165 21744 VECSGNAG
009724,000193: 32,2166 77750 LXA,1
009725,000194: 32,2167 00024 VATT1
009726,000195: 32,2170 72130 SXA,1 LXA,1
009727,000196: 32,2171 00155 MPAC +1
009728,000197: 32,2172 00026 VATT1 +2
009729,000198: 32,2173 72130 SXA,1 LXA,1
009730,000199: 32,2174 00160 MPAC +4
009731,000200: 32,2175 00030 VATT1 +4
009732,000201: 32,2176 43530 SXA,1 RVQ
009733,000202: 32,2177 00162 MPAC +6
009734,000203:
009735,000204: 32,2200 4753 LAGSLIST = ONE
009736,000205: 32,2200 00216 V01N14 VN 0114
009737,000206: 32,2201 14400 V50N00A VN 5000
009738,000207: 32,2202 6010 V00N25 EQUALS OCT31
009739,000208: 32,2202 01420 V06N16 VN 0616
009740,000209: 32,2203 4242 V00N34 EQUALS 34DEC
009741,000210: 32,2203 14420 V50N16 VN 5016
009742,000211: 32,2204 03100 00000 TSCALE 2DEC 100 B-10 # CSEC TO SEC SCALE FACTOR
009743,000212: 32,2206 03720 20SEC DEC 2000 B-14
009744,000213: 32,2207 15077 05041 RSCALE 2DEC 3.280839 B-3 # METERS TO FEET SCALE FACTOR
009745,000214: 32,2211 24402 25724 VSCALE 2DEC 3.280839 E2 B-9 # METERS/CS TO FEET/SEC SCALE FACTOR
009746,000215: 32,2213 00000 60000 AGSRND1 2OCT 0000060000
009747,000216: 32,2215 00000 60000 2OCT 0000060000
009748,000217: 32,2217 00000 60000 2OCT 0000060000
009749,000218: 32,2221 00000 37777 AGSRND2 2OCT 0000037777
009750,000219: 32,2223 00000 37777 2OCT 0000037777
009751,000220:
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009753,000222: 32,2225 00000 37777 2OCT 0000037777
009754,000223:
009755,000224: 32,2227 30,2000 SBANK= LOWSUPER # FOR SUBSEQUENT LOW 2CADRS.
End of include-file AGS_INITIALIZATION.agc. Parent file is MAIN.agc