GAP: ASSEMBLE REVISION 131 OF AGC PROGRAM LUMINARY BY NASA 2021112-091 17:53 DEC. 19, 1969Note that the date is the date the printout was made, not the date on which the program revision was released, although these happen to be very close together.
Source Code
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This source code is very close to the Apollo Guidance Computer software for the
Apollo 13 Lunar module. This revision of the Luminary 131 program is from December
of 1969, whereas there was a later revision in January of 1970, and still another
revision in February, which is the code that flew on the mission.
As far as this transcription is concerned, it was originally from a copy made in 1991 of
a printout from the collection of AGC developer Don Eyles for collector David Craig.
It was subsequently scanned by Gary Neff, reprocessed for online
presentation at the now-discontinued History of Recent Science and Technology (HRST) website
of MIT's Dibner Institute (the full-quality scans being discarded in the process),
and finally transcribed by Ron Burkey for the Virtual AGC Project. Although a
high-quality replacement scan for a completely illegible page was later provided by Gary
Neff, the reduced legibility of the reprocessed HRST posting nevertheless caused many
errors to be introduced into the transcription. Accordingly, a second scan of the same physical
printout was made in 2017 for the Virtual AGC Project's collection at the Internet Archive,
and used to correct the transcription errors. All of the scanned materials mentioned,
as well as other Luminary 131 related material, are available online.
Don Eyles apprently made additional hand-written notes in printout between 1991 and 2017,
so the two scans are not identical in that respect. The page-headings in the printout read, in part:GAP: ASSEMBLE REVISION 131 OF AGC PROGRAM LUMINARY BY NASA 2021112-091 17:53 DEC. 19, 1969Note that the date is the date the printout was made, not the date on which the program revision was released, although these happen to be very close together. |
029765,000002: ## Copyright: Public domain.
029766,000003: ## Filename: R31.agc
029767,000004: ## Purpose: A section of Luminary 1C, revision 131.
029768,000005: ## It is part of the source code for the Lunar Module's (LM)
029769,000006: ## Apollo Guidance Computer (AGC) for Apollo 13.
029770,000007: ## This file is intended to be a faithful transcription, except
029771,000008: ## that the code format has been changed to conform to the
029772,000009: ## requirements of the yaYUL assembler rather than the
029773,000010: ## original YUL assembler.
029774,000011: ## Reference: pp. 705-710
029775,000012: ## Contact: Ron Burkey <info@sandroid.org>.
029776,000013: ## Website: www.ibiblio.org/apollo/index.html
029777,000014: ## Mod history: 05/24/03 RSB. Began transcribing.
029778,000015: ## 05/14/05 RSB Corrected website reference above.
029779,000016: ## 2017-01-06 RSB Page numbers now agree with those on the
029780,000017: ## original hardcopy, as opposed to the PDF page
029781,000018: ## numbers in 1701.pdf.
029782,000019: ## 2017-02-24 RSB Proofed comment text using octopus/ProoferComments.
029783,000020: ## 2017-03-09 RSB Comment-text fixes noted in proofing Luminary 116.
029784,000021:
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Page 705 |
029786,000023: 40,3737 BANK 40
029787,000024: 40,2000 SETLOC R31LOC
029788,000025: 40,2000 BANK
029789,000026:
029790,000027: 40,3737 COUNT* $$/R31
029791,000028:
029792,000029: 40,3737 35015 R31CALL CAF PRIO3
029793,000030: 40,3740 05105 TC FINDVAC
029794,000031: 40,3741 E7,1470 EBANK= SUBEXIT
029795,000032: 40,3741 03121 76067 2CADR V83CALL
029796,000033:
029797,000034: 40,3743 05221 DSPDELAY TC FIXDELAY
029798,000035: 40,3744 00144 DEC 100 B-14
029799,000036: 40,3745 31043 CA EXTVBACT
029800,000037: 40,3746 74740 MASK BIT12
029801,000038: 40,3747 00006 EXTEND
029802,000039: 40,3750 13743 BZF DSPDELAY
029803,000040:
029804,000041: 40,3751 35017 CAF PRIO5
029805,000042: 40,3752 05072 TC NOVAC
029806,000043: 40,3753 E7,1611 EBANK= TSTRT
029807,000044: 40,3753 03113 76067 2CADR DISPN5X
029808,000045:
029809,000046: 40,3755 15261 TCF TASKOVER
029810,000047:
029811,000048: 37,3113 BANK 37
029812,000049: 37,2000 SETLOC R31
029813,000050: 37,2000 BANK
029814,000051: 37,3113 COUNT* $$/R31
029815,000052:
029816,000053: 37,3113 33407 DISPN5X CAF V16N54
029817,000054: 37,3114 04616 TC BANKCALL
029818,000055: 37,3115 20334 CADR GOMARKF
029819,000056: 37,3116 05563 TC B5OFF
029820,000057: 37,3117 05563 TC B5OFF
029821,000058: 37,3120 13113 TCF DISPN5X
029822,000059:
029823,000060: 37,3121 40103 V83CALL CS FLAGWRD7 # TEST AVERAGE G FLAG
029824,000061: 37,3122 74747 MASK AVEGFBIT
029825,000062: 37,3123 00006 EXTEND
029826,000063: 37,3124 13377 BZF MUNG? # ON - TEST MUNFLAG
029827,000064:
029828,000065: 37,3125 40104 CS FLAGWRD8
029829,000066: 37,3126 74744 MASK SURFFBIT
029830,000067: 37,3127 00006 EXTEND
029831,000068: 37,3130 13403 BZF ONEBASE # ON SURFACE - BYPASS LEMPREC
029832,000069:
029833,000070: 37,3131 06042 TC INTPRET # EXTRAPOLATE BOTH STATE VECTORS
029834,000071: 37,3132 77634 RTB
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Page 706 |
029836,000073: 37,3133 21574 LOADTIME
029837,000074: 37,3134 34041 STCALL TDEC1
029838,000075: 37,3135 27056 LEMPREC # PRECISION BASE VECTOR FOR LM
029839,000076: 37,3136 77775 VLOAD
029840,000077: 37,3137 00017 RATT1
029841,000078: 37,3140 26170 STOVL BASETHP
029842,000079: 37,3141 00025 VATT1
029843,000080: 37,3142 16105 STODL BASETHV
029844,000081: 37,3143 00015 TAT
029845,000082: 37,3144 02114 DOCMBASE STORE BASETIME # PRECISION BASE VECTOR FOR CM
029846,000083: 37,3145 34041 STCALL TDEC1
029847,000084: 37,3146 27042 CSMPREC
029848,000085: 37,3147 77775 VLOAD
029849,000086: 37,3150 00017 RATT1
029850,000087: 37,3151 26140 STOVL BASEOTP
029851,000088: 37,3152 00025 VATT1
029852,000089: 37,3153 02120 STORE BASEOTV
029853,000090: 37,3154 77776 EXIT
029854,000091:
029855,000092: 37,3155 40103 REV83 CS FLAGWRD7
029856,000093: 37,3156 74747 MASK AVEGFBIT
029857,000094: 37,3157 00006 EXTEND
029858,000095: 37,3160 13326 BZF GETRVN # IF AVEGFLAG SET, USE RN,VN
029859,000096:
029860,000097: 37,3161 40104 CS FLAGWRD8
029861,000098: 37,3162 74744 MASK SURFFBIT
029862,000099: 37,3163 00006 EXTEND
029863,000100: 37,3164 13370 BZF R31SURF # IF ON SURFACE, USE LEMAREC
029864,000101:
029865,000102: 37,3165 06042 TC INTPRET # DO CONIC EXTRAPOLATION FOR BOTH VEHICLES
029866,000103: 37,3166 77634 RTB
029867,000104: 37,3167 21574 LOADTIME
029868,000105: 37,3170 34041 STCALL TDEC1
029869,000106: 37,3171 27410 INTSTALL
029870,000107: 37,3172 43175 VLOAD CLEAR
029871,000108: 37,3173 02170 BASETHP
029872,000109: 37,3174 00263 MOONFLAG
029873,000110: 37,3175 25535 STOVL RCV
029874,000111: 37,3176 02105 BASETHV
029875,000112: 37,3177 15543 STODL VCV
029876,000113: 37,3200 02114 BASETIME
029877,000114: 37,3201 43014 BOF SET # GET APPROPRIATE MOONFLAG SETTING
029878,000115: 37,3202 04344 MOONTHIS
029879,000116: 37,3203 77205 +2
029880,000117: 37,3204 00063 MOONFLAG
029881,000118: 37,3205 77614 SET
029882,000119: 37,3206 01473 INTYPFLG # CONIC EXTRAP.
029883,000120: 37,3207 35517 STCALL TET
029884,000121: 37,3210 27106 INTEGRVS # INTEGRATION --- AT LAST ---
029885,000122: 37,3211 77775 OTHCONIC VLOAD
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Page 707 |
029887,000124: 37,3212 00001 RATT
029888,000125: 37,3213 26207 STOVL RONE
029889,000126: 37,3214 00007 VATT
029890,000127: 37,3215 36215 STCALL VONE # GET SET FOR CONIC EXTRAP., OTHER.
029891,000128: 37,3216 27410 INTSTALL
029892,000129: 37,3217 71214 SET DLOAD
029893,000130: 37,3220 01473 INTYPFLG
029894,000131: 37,3221 00015 TAT
029895,000132: 37,3222 00041 OTHINT STORE TDEC1
029896,000133: 37,3223 43175 VLOAD CLEAR
029897,000134: 37,3224 02140 BASEOTP
029898,000135: 37,3225 00263 MOONFLAG
029899,000136: 37,3226 25535 STOVL RCV
029900,000137: 37,3227 02120 BASEOTV
029901,000138: 37,3230 15543 STODL VCV
029902,000139: 37,3231 02114 BASETIME
029903,000140: 37,3232 43014 BOF SET
029904,000141: 37,3233 04344 MOONTHIS
029905,000142: 37,3234 77236 +2
029906,000143: 37,3235 00063 MOONFLAG
029907,000144: 37,3236 35517 STCALL TET
029908,000145: 37,3237 27106 INTEGRVS
029909,000146: 37,3240 52375 COMPDISP VLOAD VSU
029910,000147: 37,3241 00001 RATT
029911,000148: 37,3242 02207 RONE
029912,000149: 37,3243 65234 RTB PDDL
029913,000150: 37,3244 21725 NORMUNX1 # UNIT(RANGE) TO PD 0-5
029914,000151: 37,3245 00045 36D
029915,000152: 37,3246 77657 SL* # RESCALE AFTER NORMUNIT
029916,000153: 37,3247 20201 0,1
029917,000154: 37,3250 26201 STOVL RANGE # SCALED 2(29)M
029918,000155: 37,3251 00007 VATT
029919,000156: 37,3252 50251 VSU DOT # (VCM-VLM).UNIT(LOS), PD=0
029920,000157: 37,3253 02215 VONE
029921,000158: 37,3254 77752 SL1 # SCALED 2(7)M/CS
029922,000159: 37,3255 26203 STOVL RRATE
029923,000160: 37,3256 02207 RONE
029924,000161: 37,3257 63256 UNIT PDVL # UNIT(R) TO PD 0-5
029925,000162: 37,3260 06516 UNITZ
029926,000163: 37,3261 77624 CALL
029927,000164: 37,3262 47663 CDU*NBSM
029928,000165: 37,3263 41505 VXM PUSH # UNIT(Z)/4 TO PD 6-11
029929,000166: 37,3264 01734 REFSMMAT
029930,000167: 37,3265 72431 VPROJ VSL2 # UNIT(P)=UNIT(UZ-(UZ)PROJ(UR))
029931,000168: 37,3266 00001 0D
029932,000169: 37,3267 53445 BVSU UNIT
029933,000170: 37,3270 00007 6D
029934,000171: 37,3271 47315 PDVL VXV # UNIT(P) TO PD 12-17
029935,000172: 37,3272 00001 0D # UNIT(RL)
029936,000173: 37,3273 02215 VONE
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Page 708 |
029938,000175: 37,3274 50235 VXV DOT # (UR * VL) * UR . U(P)
029939,000176: 37,3275 00001 0D
029940,000177: 37,3276 00015 12D
029941,000178: 37,3277 77715 PDVL # SIGN TO 12-13, LOAD U(P)
029942,000179: 37,3300 75241 DOT SIGN
029943,000180: 37,3301 00007 6D
029944,000181: 37,3302 00015 12D
029945,000182: 37,3303 65512 SL2 ACOS # ARCCOS(UP.UZ(SIGN))
029946,000183: 37,3304 26205 STOVL RTHETA
029947,000184: 37,3305 00001 0D
029948,000185: 37,3306 51041 DOT BPL # IF UR.UZ NEG,
029949,000186: 37,3307 00007 6D # RTHETA = 1 - RTHETA
029950,000187: 37,3310 77315 +5
029951,000188: 37,3311 45345 DLOAD DSU
029952,000189: 37,3312 06532 DPPOSMAX
029953,000190: 37,3313 02205 RTHETA
029954,000191: 37,3314 02205 STORE RTHETA
029955,000192: 37,3315 77776 EXIT
029956,000193:
029957,000194: 37,3316 34747 CA BIT5
029958,000195: 37,3317 71043 MASK EXTVBACT
029959,000196: 37,3320 00006 EXTEND # IF ANSWERED,
029960,000197: 37,3321 15472 BZF ENDEXT # TERMINATE
029961,000198:
029962,000199: 37,3322 41043 CS EXTVBACT
029963,000200: 37,3323 74740 MASK BIT12
029964,000201: 37,3324 27043 ADS EXTVBACT # SET BIT 12
029965,000202: 37,3325 13155 TCF REV83 # AND START AGAIN.
029966,000203:
029967,000204: 37,3326 37713 GETRVN CA PRIO22 # INHIBIT SERVICER
029968,000205: 37,3327 05146 TC PRIOCHNG
029969,000206: 37,3330 06042 TC INTPRET
029970,000207: 37,3331 40375 VLOAD SETPD
029971,000208: 37,3332 01220 RN # LM STATE VECTOR IN RN,VN
029972,000209: 37,3333 00001 0
029973,000210: 37,3334 26207 STOVL RONE
029974,000211: 37,3335 01226 VN
029975,000212: 37,3336 26215 STOVL VONE # LOAD R(CSM),V(CSM) IN CASE MUNFLAG SET
029976,000213: 37,3337 01726 V(CSM) # (TO INSURE TIME COMPATABILITY)
029977,000214: 37,3340 65315 PDVL PDDL
029978,000215: 37,3341 01720 R(CSM)
029979,000216: 37,3342 01234 PIPTIME
029980,000217: 37,3343 77776 EXIT
029981,000218: 37,3344 35015 CA PRIO3
029982,000219: 37,3345 05146 TC PRIOCHNG
029983,000220: 37,3346 06042 TC INTPRET
029984,000221: 37,3347 77214 BOFF VLOAD
029985,000222: 37,3350 03347 MUNFLAG
029986,000223: 37,3351 77363 GETRVN2 # IF MUNFLAG RESET, DO CM DELTA PRECISION
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Page 709 |
029988,000225: 37,3352 60505 VXM VSR4 # CHANGE TO REFERENCE SYSTEM AND RESCALE
029989,000226: 37,3353 01734 REFSMMAT
029990,000227: 37,3354 77715 PDVL # R TO PD 0-5
029991,000228: 37,3355 76505 VXM VSL1
029992,000229: 37,3356 01734 REFSMMAT
029993,000230: 37,3357 40206 PUSH SETPD # V TO PD 5-11
029994,000231: 37,3360 00001 0
029995,000232: 37,3361 77650 GOTO
029996,000233: 37,3362 77240 COMPDISP
029997,000234:
029998,000235: 37,3363 77624 GETRVN2 CALL
029999,000236: 37,3364 27410 INTSTALL
030000,000237: 37,3365 52014 CLEAR GOTO
030001,000238: 37,3366 01673 INTYPFLG # PREC EXTRAP FOR OTHER
030002,000239: 37,3367 77222 OTHINT
030003,000240: 37,3370 06042 R31SURF TC INTPRET
030004,000241: 37,3371 77634 RTB # LM IS ON SURFACE, SO PRECISION
030005,000242: 37,3372 21574 LOADTIME # INTEGRATION USES PLANETARY INERTIAL
030006,000243: 37,3373 34041 STCALL TDEC1 # ORIENTATION SUBROUTINE
030007,000244: 37,3374 27056 LEMPREC
030008,000245: 37,3375 77650 GOTO # DO CSM CONIC
030009,000246: 37,3376 77211 OTHCONIC
030010,000247: 37,3377 40102 MUNG? CS FLAGWRD6
030011,000248: 37,3400 74744 MASK MUNFLBIT
030012,000249: 37,3401 00006 EXTEND
030013,000250: 37,3402 13326 BZF GETRVN # IF MUNFLAG SET, CSM BASE NOT NEEDED
030014,000251:
030015,000252: 37,3403 06042 ONEBASE TC INTPRET # GET CSM BASE VECTOR
030016,000253: 37,3404 52034 RTB GOTO
030017,000254: 37,3405 21574 LOADTIME
030018,000255: 37,3406 77144 DOCMBASE
030019,000256:
030020,000257: 37,3407 04066 V16N54 VN 1654
030021,000258:
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Page 710
The original program listing had no source lines on this page. |
030024,000261:
End of include-file R31.agc. Parent file is MAIN.agc