Source Code
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These source-code files are part of a reconstructed copy of Luminary 173, the
second (unflown) release of the Apollo 14 Lunar Module (LM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with reconstructed source code for Luminary 178. Changes
between revision 173 and 178 were backed out, as described by Luminary memo 167
(revision 1). The reconstruction was verified by matching memory-bank checksums
to those listed in drawing 2021152N. Note that page numbers in the reconstructed
code match those for the baseline log section mentioned in each file's changelog;
the page numbers for a real Luminary 173 listing would be different.
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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052874,000002: ## Copyright: Public domain.
052875,000003: ## Filename: INFLIGHT_ALIGNMENT_ROUTINES.agc
052876,000004: ## Purpose: A section of Luminary revision 173.
052877,000005: ## It is part of the reconstructed source code for the second
052878,000006: ## (unflown) release of the flight software for the Lunar
052879,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 14.
052880,000008: ## The code has been recreated from a reconstructed copy of
052881,000009: ## Luminary 178, as well as Luminary memo 167 (revision 1).
052882,000010: ## It has been adapted such that the resulting bugger words
052883,000011: ## exactly match those specified for Luminary 173 in NASA
052884,000012: ## drawing 2021152N, which gives relatively high confidence
052885,000013: ## that the reconstruction is correct.
052886,000014: ## Reference: pp. 1238-1247
052887,000015: ## Assembler: yaYUL
052888,000016: ## Contact: Ron Burkey <info@sandroid.org>.
052889,000017: ## Website: www.ibiblio.org/apollo/index.html
052890,000018: ## Mod history: 2019-09-18 MAS Created from Luminary 178.
052891,000019:
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Page 1238
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052893,000021: 22,3772 BANK 22
052894,000022: 23,2000 SETLOC INFLIGHT
052895,000023: 23,2000 BANK
052896,000024:
052897,000025: 23,3245 E5,1642 EBANK= XSM
052898,000026:
052899,000027: # CALCGTA COMPUTES THE GYRO TORQUE ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION.
052900,000028:
052901,000029: # THE INPUT IS THE DESIRED STABLE MEMBER COORDINATES REFERRED TO PRESENT STABLE MEMBER COORDINATES. THE THREE
052902,000030: # HALF-UNIT VECTORS ARE STORED AT XDC, YDC, AND ZDC.
052903,000031:
052904,000032: # THE OUTPUTS ARE THE THREE GYRO TORQUING ANGLES TO BE APPLIED TO THE Y, Z, AND X GYROS AND ARE STORED DP AT IGC,
052905,000033: # MGC, AND OGC RESPECTIVELY.
052906,000034:
052907,000035: 23,3245 COUNT* $$/INFLT
052908,000036: 23,3245 71220 CALCGTA ITA DLOAD # PUSHDOWN 00-03,16D-27D,34D-37D
052909,000037: 23,3246 00051 S2 # XDC = (XD1 XD2 XD3)
052910,000038: 23,3247 02665 XDC # YDC = (YD1 YD2 YD3)
052911,000039: 23,3250 65325 PDDL PDDL # ZDC = (ZD1 ZD2 ZD3)
052912,000040: 23,3251 06520 HI6ZEROS
052913,000041: 23,3252 02671 XDC +4
052914,000042: 23,3253 55476 DCOMP VDEF
052915,000043: 23,3254 77656 UNIT
052916,000044: 23,3255 14027 STODL ZPRIME # ZP = UNIT(-XD3 0 XD1) = (ZP1 ZP2 ZP3)
052917,000045: 23,3256 00027 ZPRIME
052918,000046:
052919,000047: 23,3257 77742 SR1
052920,000048: 23,3260 14023 STODL SINTH # SIN(IGC) = ZP1
052921,000049: 23,3261 00033 ZPRIME +4
052922,000050: 23,3262 77742 SR1
052923,000051: 23,3263 34021 STCALL COSTH # COS(IGC) = ZP3
052924,000052: 23,3264 47316 ARCTRIG
052925,000053:
052926,000054: 23,3265 16742 STODL IGC # Y GYRO TORQUING ANGLE FRACTION OF REV.
052927,000055: 23,3266 02667 XDC +2
052928,000056: 23,3267 77742 SR1
052929,000057: 23,3270 14023 STODL SINTH # SIN(MGC) = XD2
052930,000058: 23,3271 00027 ZPRIME
052931,000059:
052932,000060: 23,3272 65205 DMP PDDL
052933,000061: 23,3273 02671 XDC +4 # PD00 = (ZP1)(XD3)
052934,000062: 23,3274 00033 ZPRIME +4
052935,000063:
052936,000064: 23,3275 45205 DMP DSU
052937,000065: 23,3276 02665 XDC # MPAC = (ZP3)(XD1)
052938,000066: 23,3277 77626 STADR
052939,000067: 23,3300 43756 STCALL COSTH # COS(MGC) = MPAC - PD00
052940,000068: 23,3301 47316 ARCTRIG
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Page 1239
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052942,000070: 23,3302 26744 STOVL MGC # Z GYRO TORQUING ANGLE FRACTION OF REV.
052943,000071: 23,3303 00027 ZPRIME
052944,000072: 23,3304 77641 DOT
052945,000073: 23,3305 02701 ZDC
052946,000074: 23,3306 24021 STOVL COSTH # COS(OGC) = ZP . ZDC
052947,000075: 23,3307 00027 ZPRIME
052948,000076: 23,3310 77641 DOT
052949,000077: 23,3311 02673 YDC
052950,000078: 23,3312 34023 STCALL SINTH # SIN(OGC) = ZP . YDC
052951,000079: 23,3313 47316 ARCTRIG
052952,000080:
052953,000081: 23,3314 36740 STCALL OGC # X GYRO TORQUING ANGLE FRACTION OF REV.
052954,000082: 23,3315 00051 S2
052955,000083:
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Page 1240
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052957,000085: # ARCTRIG COMPUTES AN ANGLE GIVEN THE SINE AND COSINE OF THIS ANGLE.
052958,000086:
052959,000087: # THE INPUTS ARE SIN/4 AND COS/4 STORED DP AT SINTH AND COSTH.
052960,000088:
052961,000089: # THE OUTPUT IS THE CALCULATED ANGLE BETWEEN +.5 AND -.5 REVOLUTIONS AND STORED AT THETA. THE OUTPUT IS ALSO
052962,000090: # AVAILABLE AT MPAC.
052963,000091:
052964,000092: 23,3316 51545 ARCTRIG DLOAD ABS # PUSHDOWN 16D-21D
052965,000093: 23,3317 00023 SINTH
052966,000094: 23,3320 50025 DSU BMN
052967,000095: 23,3321 07532 QTSN45 # ABS(SIN/4) - SIN(45)/4
052968,000096: 23,3322 47331 TRIG1 # IF (-45,45) OR (135,-135)
052969,000097:
052970,000098: 23,3323 72545 DLOAD SL1 # (45,135) OR (-135,-45)
052971,000099: 23,3324 00021 COSTH
052972,000100: 23,3325 75326 ACOS SIGN
052973,000101: 23,3326 00023 SINTH
052974,000102: 23,3327 00025 STORE THETA # X = ARCCOS(COS) WITH SIGN(SIN)
052975,000103: 23,3330 77616 RVQ
052976,000104:
052977,000105: 23,3331 72545 TRIG1 DLOAD SL1 # (-45,45) OR (135,-135)
052978,000106: 23,3332 00023 SINTH
052979,000107: 23,3333 77736 ASIN
052980,000108: 23,3334 14025 STODL THETA # X = ARCSIN(SIN) WITH SIGN(SIN)
052981,000109: 23,3335 00021 COSTH
052982,000110: 23,3336 77640 BMN
052983,000111: 23,3337 47342 TRIG2 # IF (135,-135)
052984,000112:
052985,000113: 23,3340 43545 DLOAD RVQ
052986,000114: 23,3341 00025 THETA # X = ARCSIN(SIN) (-45,45)
052987,000115:
052988,000116: 23,3342 75345 TRIG2 DLOAD SIGN # (135,-135)
052989,000117: 23,3343 06516 HIDPHALF
052990,000118: 23,3344 00023 SINTH
052991,000119: 23,3345 77625 DSU
052992,000120: 23,3346 00025 THETA
052993,000121: 23,3347 00025 STORE THETA # X = .5 WITH SIGN(SIN) - ARCSIN(SIN)
052994,000122: 23,3350 77616 RVQ # (+) - (+) OR (-) - (-)
052995,000123:
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Page 1241
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052997,000125: # SMNB, NBSM, AND AXISROT, WHICH USED TO APPEAR HERE, HAVE BEEN
052998,000126: # COMBINED IN A ROUTINE CALLED AX*SR*T, WHICH APPEARS AMONG THE POWERED
052999,000127: # FLIGHT SUBROUTINES.
053000,000128:
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Page 1242
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053002,000130: # CALCGA COMPUTES THE CDU DRIVING ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION.
053003,000131:
053004,000132: # THE INPUTS ARE 1) THE NAVIGATION BASE COORDINATES REFERRED TO ANY COORDINATE SYSTEM. THE THREE HALF-UNIT
053005,000133: # VECTORS ARE STORED AT XNB,YNB, AND ZNB. 2) THE DESIRED STABLE MEMBER COORDINATES REFERRED TO THE SAME
053006,000134: # COORDINATE SYSTEM ARE STORED AT XSM, YSM, AND ZSM.
053007,000135:
053008,000136: # THE OUTPUTS ARE THE THREE CDU DRIVING ANGLES AND ARE STORED SP AT THETAD, THETAD +1, AND THETAD +2.
053009,000137:
053010,000138: 23,3351 77601 CALCGA SETPD # PUSHDOWN 00-05, 16D-21D, 34D-37D
053011,000139: 23,3352 00001 0
053012,000140: 23,3353 47375 VLOAD VXV
053013,000141: 23,3354 02665 XNB # XNB = OGA (OUTER GIMBAL AXIS)
053014,000142: 23,3355 02651 YSM # YSM = IGA (INNER GIMBAL AXIS)
053015,000143: 23,3356 41456 UNIT PUSH # PD0 = UNIT(OGA X IGA) = MGA
053016,000144:
053017,000145: 23,3357 44041 DOT ITA
053018,000146: 23,3360 02701 ZNB
053019,000147: 23,3361 00051 S2
053020,000148: 23,3362 24021 STOVL COSTH # COS(OG) = MGA . ZNB
053021,000149: 23,3363 00001 0
053022,000150: 23,3364 77641 DOT
053023,000151: 23,3365 02673 YNB
053024,000152: 23,3366 34023 STCALL SINTH # SIN(OG) = MGA . YNB
053025,000153: 23,3367 47316 ARCTRIG
053026,000154: 23,3370 26740 STOVL OGC
053027,000155: 23,3371 00001 0
053028,000156:
053029,000157: 23,3372 50235 VXV DOT # PROVISION FOR MG ANGLE OF 90 DEGREES
053030,000158: 23,3373 02665 XNB
053031,000159: 23,3374 02651 YSM
053032,000160: 23,3375 77752 SL1
053033,000161: 23,3376 24021 STOVL COSTH # COS(MG) = IGA . (MGA X OGA)
053034,000162: 23,3377 02651 YSM
053035,000163: 23,3400 77641 DOT
053036,000164: 23,3401 02665 XNB
053037,000165: 23,3402 34023 STCALL SINTH # SIN(MG) = IGA . OGA
053038,000166: 23,3403 47316 ARCTRIG
053039,000167: 23,3404 02744 STORE MGC
053040,000168:
053041,000169: 23,3405 45246 ABS DSU
053042,000170: 23,3406 07534 .166...
053043,000171: 23,3407 77644 BPL
053044,000172: 23,3410 47427 GIMLOCK1 # IF ANGLE GREATER THAN 60 DEGREES
053045,000173:
053046,000174: 23,3411 50375 CALCGA1 VLOAD DOT
053047,000175: 23,3412 02657 ZSM
053048,000176: 23,3413 00001 0
053049,000177: 23,3414 24021 STOVL COSTH # COS(IG) = ZSM . MGA
053050,000178: 23,3415 02643 XSM
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Page 1243
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053052,000180: 23,3416 45441 DOT STADR
053053,000181: 23,3417 43754 STCALL SINTH # SIN(IG) = XSM . MGA
053054,000182: 23,3420 47316 ARCTRIG
053055,000183:
053056,000184: 23,3421 26742 STOVL IGC
053057,000185: 23,3422 02740 OGC
053058,000186: 23,3423 77634 RTB
053059,000187: 23,3424 21621 V1STO2S
053060,000188: 23,3425 34322 STCALL THETAD
053061,000189: 23,3426 00051 S2
053062,000190:
053063,000191: 23,3427 77776 GIMLOCK1 EXIT
053064,000192: 23,3430 05600 TC ALARM
053065,000193: 23,3431 00401 OCT 00401
053066,000194: 23,3432 05515 TC UPFLAG # GIMBAL LOCK HAS OCCURED
053067,000195: 23,3433 00056 ADRES GLOKFAIL
053068,000196:
053069,000197: 23,3434 06042 TC INTPRET
053070,000198: 23,3435 77650 GOTO
053071,000199: 23,3436 47411 CALCGA1
053072,000200:
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Page 1244
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053074,000202: # AXISGEN COMPUTES THE COORDINATES OF ONE COORDINATE SYSTEM REFERRED TO ANOTHER COORDINATE SYSTEM.
053075,000203:
053076,000204: # THE INPUTS ARE 1) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM A STORED AT STARAD. 2) THE STAR2 VECTOR
053077,000205: # REFERRED TO COORDINATE SYSTEM A STORED AT STARAD +6. 3) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM B STORED
053078,000206: # AT LOCATION 6 OF THE VAC AREA. 4) THE STAR2 VECTOR REFERRED TO COORDINATE SYSTEM B STORED AT LOCATION 12D OF
053079,000207: # THE VAC AREA.
053080,000208:
053081,000209: # THE OUTPUT DEFINES COORDINATE SYSTEM A REFERRED TO COORDINATE SYSTEM B. THE THREE HALF-UNIT VECTORS ARE STORED
053082,000210: # AT LOCATIONS XDC, XDC +6, XDC +12D, AND STARAD, STARAD +6, STARAD +12D.
053083,000211:
053084,000212: 23,3437 66370 AXISGEN AXT,1 SSP # PUSHDOWN 00-30D,34D-37D
053085,000213: 23,3440 02714 STARAD +6
053086,000214: 23,3441 00051 S1
053087,000215: 23,3442 02700 STARAD -6
053088,000216:
053089,000217: 23,3443 77601 SETPD
053090,000218: 23,3444 00001 0
053091,000219: 23,3445 46773 AXISGEN1 VLOAD* VXV* # 06D UA = S1
053092,000220: 23,3446 02723 STARAD +12D,1 # STARAD +00D UB = S1
053093,000221: 23,3447 02731 STARAD +18D,1
053094,000222: 23,3450 77656 UNIT # 12D VA = UNIT(S1 X S2)
053095,000223: 23,3451 06731 STORE STARAD +18D,1 # STARAD +06D VB = UNIT(S1 X S2)
053096,000224: 23,3452 77773 VLOAD*
053097,000225: 23,3453 02723 STARAD +12D,1
053098,000226:
053099,000227: 23,3454 76433 VXV* VSL1
053100,000228: 23,3455 02731 STARAD +18D,1 # 18D WA = UA X VA
053101,000229: 23,3456 06737 STORE STARAD +24D,1 # STARAD +12D WB = UB X VB
053102,000230:
053103,000231: 23,3457 77700 TIX,1
053104,000232: 23,3460 47445 AXISGEN1
053105,000233:
053106,000234: 23,3461 66160 AXC,1 SXA,1
053107,000235: 23,3462 00006 6
053108,000236: 23,3463 00036 30D
053109,000237:
053110,000238: 23,3464 66370 AXT,1 SSP
053111,000239: 23,3465 00022 18D
053112,000240: 23,3466 00051 S1
053113,000241: 23,3467 00006 6
053114,000242:
053115,000243: 23,3470 66374 AXT,2 SSP
053116,000244: 23,3471 00006 6
053117,000245: 23,3472 00052 S2
053118,000246: 23,3473 00002 2
053119,000247:
053120,000248: 23,3474 76720 AXISGEN2 XCHX,1 VLOAD*
053121,000249: 23,3475 00036 30D # X1=-6 X2=+6 X1=-6 X2=+4 X1=-6 X2=+2
053122,000250: 23,3476 00001 0,1
053123,000251:
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Page 1245
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053125,000253: 23,3477 62757 VXSC* PDVL* # J=(UA)(UB1) J=(UA)(UB2) J=(UA)(UB3)
053126,000254: 23,3500 75062 STARAD +6,2
053127,000255: 23,3501 00007 6,1
053128,000256: 23,3502 77757 VXSC*
053129,000257: 23,3503 75054 STARAD +12D,2
053130,000258: 23,3504 30031 STOVL* 24D # K=(VA)(VB1) J=(VA)(VB2) J=(VA)(VB3)
053131,000259: 23,3505 00015 12D,1
053132,000260:
053133,000261: 23,3506 53357 VXSC* VAD
053134,000262: 23,3507 75046 STARAD +18D,2 # L=(WA)(WB1) J=(WA)(WB2) J=(WA)(WB3)
053135,000263: 23,3510 76455 VAD VSL1
053136,000264: 23,3511 00031 24D
053137,000265: 23,3512 53520 XCHX,1 UNIT
053138,000266: 23,3513 00036 30D
053139,000267: 23,3514 06707 STORE XDC +18D,1 # XDC = L+J+K YDC = L+J+K ZDC = L+J+K
053140,000268:
053141,000269: 23,3515 77700 TIX,1
053142,000270: 23,3516 47517 AXISGEN3
053143,000271:
053144,000272: 23,3517 77704 AXISGEN3 TIX,2
053145,000273: 23,3520 47474 AXISGEN2
053146,000274:
053147,000275: 23,3521 77775 VLOAD
053148,000276: 23,3522 02665 XDC
053149,000277: 23,3523 26707 STOVL STARAD
053150,000278: 23,3524 02673 YDC
053151,000279: 23,3525 26715 STOVL STARAD +6
053152,000280: 23,3526 02701 ZDC
053153,000281: 23,3527 02723 STORE STARAD +12D
053154,000282:
053155,000283: 23,3530 77616 RVQ
053156,000284:
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Page 1246
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053158,000286: 23,3531 05520 26075 QTSN45 2DEC .1768
053159,000287: 23,3533 05252 25253 .166... 2DEC .1666666667
053160,000288:
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Page 1247
There is no source code on this page of the original assembly listing.
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End of include-file INFLIGHT_ALIGNMENT_ROUTINES.agc. Parent file is MAIN.agc