Source Code
![]() |
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. |
008447,000002: ## Copyright: Public domain.
008448,000003: ## Filename: AGS_INITIALIZATION.agc
008449,000004: ## Purpose: A section of Luminary revision 116.
008450,000005: ## It is part of the source code for the Lunar Module's (LM)
008451,000006: ## Apollo Guidance Computer (AGC) for Apollo 12.
008452,000007: ## This file is intended to be a faithful transcription, except
008453,000008: ## that the code format has been changed to conform to the
008454,000009: ## requirements of the yaYUL assembler rather than the
008455,000010: ## original YUL assembler.
008456,000011: ## Reference: pp. 207-211
008457,000012: ## Assembler: yaYUL
008458,000013: ## Contact: Ron Burkey <info@sandroid.org>.
008459,000014: ## Website: www.ibiblio.org/apollo/index.html
008460,000015: ## Mod history: 2017-01-22 MAS Created from Luminary 99.
008461,000016: ## 2017-02-10 NV Updated for Luminary 116.
008462,000017: ## 2017-03-01 RSB Proofed comment text by diff vs Luminary 131
008463,000018: ## and fixed error found.
008464,000019:
![]() |
Page 207 |
008466,000021:
008467,000022: # PROGRAM NAME: AGS INITIALIZATION (R47)
008468,000023:
008469,000024: # WRITTEN BY: RHODE/KILROY/FOLLETT
008470,000025:
008471,000026: # MOD NO. : 0
008472,000027: # DATE: 23 MARCH 1967
008473,000028: # MOD BY: KILROY
008474,000029:
008475,000030: # MOD NO.: 1
008476,000031: # DATE: 28 OCTOBER 1967
008477,000032: # MOD BY: FOLLETT
008478,000033:
008479,000034: # FUNCT. DESC.: (1) TO PROVIDE THE AGS ABORT ELECTRONICS ASSEMBLY (AEA) WITH THE LEM AND CSM STATE VECTORS
008480,000035: # (POSITION,VELOCITY,TIME) IN LEM IMU COORDINATES BY MEANS OF THE LGC DIGITAL DOWNLINK.
008481,000036:
008482,000037: # (2) TO ZERO THE ICDU, LGC AND AEA GIMBAL ANGLE COUNTERS SIMULTANEOUSLY IN ORDER TO ESTABLISH A
008483,000038: # COMMON ZERO REFERENCE FOR THE MEASUREMENT OF GIMBAL (EULER) ANGLES WHICH DEFINE LEM ATTITUDE
008484,000039:
008485,000040: # (3) TO ESTABLISH THE GROUND ELAPSED TIME OF AEA CLOCK ZERO. (IF AN AEA CLOCK ZERO IS
008486,000041: # REQUESTED DURING THIS PROGRAM
008487,000042:
008488,000043: # LOG SECTION: AGS INITIALIZATION
008489,000044:
008490,000045: # CALLING SEQ: PROGRAM IS ENTERED WHEN ASTRONAUT KEYS V47E ON DSKY.
008491,000046: # R47 MAY BE CALLED AT ANY TIME EXCEPT WHEN ANOTHER EXTENDED VERB IS IN PROGRESS
008492,000047:
008493,000048: # SUBROUTINES
008494,000049: # CALLED:
008495,000050:
008496,000051: # NORMAL EXIT: ENDEXT
008497,000052:
008498,000053: # ALARM/ABORT: ALARM - BAD REFSMMAT - CODE:220
008499,000054: # OPERATOR ERROR IF V47 SELECTED DURING ANOTHER EXTENDED VERB.
008500,000055:
008501,000056: # ERASABLES
008502,000057: # USED: SAMPTIME (2) TIME OF :ENTER: KEYSTROKE
008503,000058: # AGSK (2) GROUND ELAPSED TIME OF THE AEA CLOCK :ZERO:
008504,000059: # AGSBUFF (140) CONTAINS AGS INITIALIZATION DATA (SEE :OUTPUT: BELOW)
008505,000060: # AGSWORD (1) PREVIOUS DOWNLIST SAVED HERE
008506,000061:
008507,000062: 05,2447 E4,1600 EBANK= AGSBUFF
008508,000063:
008509,000064: 40,2000 BANK 40
008510,000065: 32,2000 SETLOC R47
008511,000066: 32,2000 BANK
008512,000067:
008513,000068: 32,2005 COUNT* $$/R47
008514,000069:
008515,000070: 32,2005 34737 AGSINIT CAF REFSMBIT
008516,000071: 32,2006 70077 MASK FLAGWRD3 # CHECK REFSMFLG.
008517,000072: 32,2007 10000 CCS A
![]() |
Page 208 |
008519,000074: 32,2010 02017 TC REDSPTEM # REFSMMAT IS OK
008520,000075: 32,2011 05567 TC ALARM # REFSMMAT IS BAD
008521,000076: 32,2012 00220 OCT 220
008522,000077: 32,2013 05472 TC ENDEXT
008523,000078:
008524,000079: 32,2014 00006 NEWAGS EXTEND
008525,000080: 32,2015 30014 DCA SAMPTIME # TIME OF THE :ENTER: KEYSTROKE
008526,000081: 32,2016 53421 DXCH AGSK # BECOMES NEW AEA CLOCK :ZERO:
008527,000082:
008528,000083: 32,2017 00006 REDSPTEM EXTEND
008529,000084: 32,2020 31421 DCA AGSK
008530,000085: 32,2021 53051 DXCH DSPTEMX
008531,000086: 32,2022 32172 AGSDISPK CAF V06N16
008532,000087: 32,2023 04616 TC BANKCALL # R1 = 00XXX. HRS., R2 = 000XX MIN.,
008533,000088: 32,2024 20334 CADR GOMARKF # R3 = 0XX.XX SEC.
008534,000089: 32,2025 05472 TC ENDEXT # TERMINATE RETURN
008535,000090: 32,2026 02036 TC AGSVCALC # PROCEED RETURN
008536,000091: 32,2027 44746 CS BIT6 # IS ENTER VIA A V32
008537,000092: 32,2030 60154 AD MPAC
008538,000093: 32,2031 00006 EXTEND
008539,000094: 32,2032 12014 BZF NEWAGS # YES, USE KEYSTROKE TIME FOR NEW AGSK
008540,000095:
008541,000096: 32,2033 00006 EXTEND # NO, NEW AGSK LOADED VIA V25
008542,000097: 32,2034 31051 DCA DSPTEMX # LOADED INTO DSPTEMX BY KEYING
008543,000098: 32,2035 02016 TC REDSPTEM -1 # V25E FOLLOWED BY HRS.,MINS.,SECS.
008544,000099: # DISPLAY THE NEW K
008545,000100:
008546,000101: 32,2036 06042 AGSVCALC TC INTPRET
008547,000102: 32,2037 77614 SET
008548,000103: 32,2040 01076 NODOFLAG # DONT ALLOW V37
008549,000104: 32,2041 77414 SET EXIT
008550,000105: 32,2042 02076 XDSPFLAG
008551,000106:
008552,000107: 32,2043 32172 CAF V06N16
008553,000108: 32,2044 04616 TC BANKCALL
008554,000109: 32,2045 20621 CADR EXDSPRET
008555,000110:
008556,000111: 32,2046 06042 TC INTPRET # EXTRAPOLATE LEM AND CSM STATE VECTORS
008557,000112: 32,2047 77634 RTB # TO THE PRESENT TIME
008558,000113: 32,2050 21574 LOADTIME # LOAD MPAC WITH TIME2,TIME1
008559,000114: 32,2051 34041 STCALL TDEC1 # CALCULATE LEM STATE VECTOR
008560,000115: 32,2052 27060 LEMPREC
008561,000116: 32,2053 77624 CALL # CALL ROUTINE TO CONVERT TO SM COORDS AND
008562,000117: 32,2054 64132 SCALEVEC # PROVIDE PROPER SCALING
008563,000118: 32,2055 16201 STODL AGSBUFF # (LEMPREC AND CSMPREC LEAVE TDEC1 IN TAT)
008564,000119: 32,2056 00015 TAT # TAT = TIME TO WHICH RATT1 AND VATT1 ARE
008565,000120: 32,2057 34041 STCALL TDEC1 # COMPUTED (CSEC SINCE CLOCK START B-28).
008566,000121: 32,2060 27044 CSMPREC # CALCULATE CSM STATE VECTOR FOR SAME TIME
008567,000122: 32,2061 77624 CALL
008568,000123: 32,2062 64132 SCALEVEC
![]() |
Page 209 |
008570,000125: 32,2063 16207 STODL AGSBUFF +6
008571,000126: 32,2064 00015 TAT
008572,000127: 32,2065 56225 DSU DDV # CALCULATE AND STORE THE TIME
008573,000128: 32,2066 02021 AGSK
008574,000129: 32,2067 24175 TSCALE
008575,000130: 32,2070 02215 STORE AGSBUFF +12D
008576,000131: 32,2071 77776 EXIT
008577,000132:
008578,000133: 32,2072 34753 CAF LAGSLIST
008579,000134: 32,2073 54333 TS DNLSTCOD
008580,000135:
008581,000136: 32,2074 32176 CAF 20SEC # DELAY FOR 20 SEC WHILE THE AGS
008582,000137: 32,2075 04616 TC BANKCALL # DOWNLIST IS TRANSMITTED
008583,000138: 32,2076 01736 CADR DELAYJOB
008584,000139:
008585,000140: 32,2077 31321 CA AGSWORD
008586,000141: 32,2100 54333 TS DNLSTCOD # RETURN TO THE OLD DOWNLIST
008587,000142: 32,2101 34744 CAF IMUSEBIT
008588,000143: 32,2102 70074 MASK FLAGWRD0 # CHECK IMUSE FLAG.
008589,000144: 32,2103 10000 CCS A
008590,000145: 32,2104 02122 TC AGSEND # IMU IS BEING USED - DO NOT ZERO
008591,000146: 32,2105 11301 CKSTALL CCS IMUCADR # CHECK FOR IMU USAGE WHICH AVOIDS THE
008592,000147: 32,2106 12111 TCF +3 # IMUSE BIT: I.E., IMU COMPENSATION.
008593,000148: 32,2107 12115 TCF +6 # FREE. GO AHEAD WITH THE IMU ZERO.
008594,000149: 32,2110 12111 TCF +1
008595,000150: 32,2111 34363 +3 CAF TEN # WAIT .1 SEC AND TRY AGAIN.
008596,000151: 32,2112 04616 TC BANKCALL
008597,000152: 32,2113 01736 CADR DELAYJOB
008598,000153: 32,2114 12105 TCF CKSTALL
008599,000154:
008600,000155: 32,2115 04616 +6 TC BANKCALL # IMU IS NOT IN USE
008601,000156: 32,2116 16706 CADR IMUZERO # SET IMU ZERO DISCRETE FOR 320MSECS
008602,000157: 32,2117 04616 TC BANKCALL # WAIT 3 SEC FOR COUNTERS TO INCREMENT
008603,000158: 32,2120 17710 CADR IMUSTALL
008604,000159: 32,2121 02122 TC AGSEND
008605,000160: 32,2122 05516 AGSEND TC DOWNFLAG # ALLOW V37
008606,000161: 32,2123 00054 ADRES NODOFLAG
008607,000162:
008608,000163: 32,2124 32173 CAF V50N16
008609,000164: 32,2125 04616 TC BANKCALL
008610,000165: 32,2126 20342 CADR GOMARK3
008611,000166: 32,2127 15472 TCF ENDEXT
008612,000167: 32,2130 15472 TCF ENDEXT
008613,000168: 32,2131 05472 TC ENDEXT
008614,000169:
008615,000170: 32,2132 64375 SCALEVEC VLOAD MXV
008616,000171: 32,2133 00025 VATT1
008617,000172: 32,2134 01734 REFSMMAT
008618,000173: 32,2135 72561 VXSC VSL2
008619,000174: 32,2136 24202 VSCALE
![]() |
Page 210 |
008621,000176: 32,2137 53255 VAD VAD # THIS SECTION ROUNDS THE VECTOR, AND
008622,000177: 32,2140 24204 AGSRND1 # CORRECTS FOR THE FACT THAT THE AGS
008623,000178: 32,2141 24212 AGSRND2 # IS A 2 S COMPLIMENT MACHINE WHILE THE
008624,000179: 32,2142 77634 RTB # LGC IS A 1 S COMPLIMENT MACHINE.
008625,000180: 32,2143 21773 VECSGNAG
008626,000181: 32,2144 24025 STOVL VATT1
008627,000182: 32,2145 00017 RATT1
008628,000183: 32,2146 74321 MXV VXSC
008629,000184: 32,2147 01734 REFSMMAT
008630,000185: 32,2150 24200 RSCALE
008631,000186: 32,2151 53212 VSL8 VAD # AGAIN THIS SECTION ROUNDS. TWO VECTORS
008632,000187: 32,2152 24204 AGSRND1 # ARE ADDED TO DEFEAT ALSIGNAG IN THE
008633,000188: 32,2153 47055 VAD RTB # CASE OF A HIGH-ORDER ZERO COUPLED WITH
008634,000189: 32,2154 24212 AGSRND2 # A LOW ORDER NEGATIVE PART.
008635,000190: 32,2155 21773 VECSGNAG
008636,000191: 32,2156 77750 LXA,1
008637,000192: 32,2157 00024 VATT1
008638,000193: 32,2160 72130 SXA,1 LXA,1
008639,000194: 32,2161 00155 MPAC +1
008640,000195: 32,2162 00026 VATT1 +2
008641,000196: 32,2163 72130 SXA,1 LXA,1
008642,000197: 32,2164 00160 MPAC +4
008643,000198: 32,2165 00030 VATT1 +4
008644,000199: 32,2166 43530 SXA,1 RVQ
008645,000200: 32,2167 00162 MPAC +6
008646,000201:
008647,000202: 32,2170 4753 LAGSLIST = ONE
008648,000203: 32,2170 00216 V01N14 VN 0114
008649,000204: 32,2171 14400 V50N00A VN 5000
008650,000205: 32,2172 6010 V00N25 EQUALS OCT31
008651,000206: 32,2172 01420 V06N16 VN 0616
008652,000207: 32,2173 4242 V00N34 EQUALS 34DEC
008653,000208: 32,2173 14420 V50N16 VN 5016
008654,000209: 32,2174 03100 00000 TSCALE 2DEC 100 B-10 # CSEC TO SEC SCALE FACTOR
008655,000210: 32,2176 03720 20SEC DEC 2000 B-14
008656,000211: 32,2177 15077 05041 RSCALE 2DEC 3.280839 B-3 # METERS TO FEET SCALE FACTOR
008657,000212: 32,2201 24402 25724 VSCALE 2DEC 3.280839 E2 B-9 # METERS/CS TO FEET/SEC SCALE FACTOR
008658,000213: 32,2203 00000 60000 AGSRND1 2OCT 0000060000
008659,000214: 32,2205 00000 60000 2OCT 0000060000
008660,000215: 32,2207 00000 60000 2OCT 0000060000
008661,000216: 32,2211 00000 37777 AGSRND2 2OCT 0000037777
008662,000217: 32,2213 00000 37777 2OCT 0000037777
![]() |
Page 211 |
008664,000219: 32,2215 00000 37777 2OCT 0000037777
008665,000220:
008666,000221: 32,2217 30,2000 SBANK= LOWSUPER # FOR SUBSEQUENT LOW 2CADRS.
008667,000222:
End of include-file AGS_INITIALIZATION.agc. Parent file is MAIN.agc