Source Code
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These source-code files are part of a reconstructed copy of Comanche 67, the
Apollo Guidance Computer (AGC) Command Module (CM) software for Apollo 12.
They have been adapted from sources files for Comanche 55, and updated via
disassembly of binary dumps of original core rope memory modules, part numbers
2003972-1081, 2003972-1091, 2003972-1111, 2003972-1121, 2003972-1131, and 2003972-1141.
Since only binary dumps (rather than listings) of Comanche 67 are available as source material,
all comments and labels are approximate.
They have been taken from other AGC programs where possible, or, in some places, written
from scratch to match what we believe would have been in the original listing.
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051207,000002: ## Copyright: Public domain.
051208,000003: ## Filename: LATITUDE_LONGITUDE_SUBROUTINES.agc
051209,000004: ## Purpose: A section of Comanche revision 067.
051210,000005: ## It is part of the reconstructed source code for the flight
051211,000006: ## software for the Command Module's (CM) Apollo Guidance Computer
051212,000007: ## (AGC) for Apollo 12. No original listings of this program are
051213,000008: ## available; instead, this file was created via dissassembly of
051214,000009: ## dumps of Comanche 067 core rope modules and comparison with
051215,000010: ## other AGC programs.
051216,000011: ## Assembler: yaYUL
051217,000012: ## Contact: Ron Burkey <info@sandroid.org>.
051218,000013: ## Website: www.ibiblio.org/apollo/index.html
051219,000014: ## Mod history: 2023-08-16 MAS Created from Comanche 055.
051220,000015:
051221,000016: # SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
051222,000017:
051223,000018: # CALLING SEQUENCE
051224,000019: # L-1 CALL
051225,000020: # L LAT-LONG
051226,000021:
051227,000022: # SUBROUTINES USED
051228,000023: # R-TO-RP, ARCTAN, SETGAMMA, SETRE
051229,000024:
051230,000025: # ERASABLE INIT. REQ.
051231,000026: # AXO, -AYO, AZO, TEPHEM (SET AT LAUNCH TIME)
051232,000027: # ALPHAV = POSITION VECTOR METERS B-29
051233,000028: # MPAC -- TIME (CSECS B-28)
051234,000029: # ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
051235,000030: # LUNAFLAG=0 FOR EARTH, 1 FOR MOON
051236,000031:
051237,000032: # OUTPUT
051238,000033: # LATITUDE IN LAT (REVS. B-0)
051239,000034: # LONGITUDE IN LONG (REVS. B-0)
051240,000035: # ALTITUDE IN ALT METERS B-29
051241,000036:
051242,000037: 30,3750 BANK 30
051243,000038: 13,2000 SETLOC LATLONG
051244,000039: 13,2000 BANK
051245,000040:
051246,000041: 13,2400 COUNT 13/LT-LG
051247,000042:
051248,000043: 13,2400 E4,1551 EBANK= ALPHAV
051249,000044: 13,2400 40220 LAT-LONG STQ SETPD
051250,000045: 13,2401 02242 INCORPEX
051251,000046: 13,2402 00001 0D
051252,000047: 13,2403 24007 STOVL 6D # SAVE TIME IN 6-7D FOR R-TO-RP
051253,000048: 13,2404 02152 ALPHAV
051254,000049: 13,2405 51406 PUSH ABVAL # 0-5D= R FOR R-TO-RP
051255,000050: 13,2406 16310 STODL ALPHAM # ABS. VALUE OF R FOR ALT FORMULA BELOW
051256,000051: 13,2407 11566 ZEROVEC # SET MPAC=0 FOR EARTH, NON-ZERO FOR MOON
051257,000052: 13,2410 71414 BOFF COS # USE COS(0) TO GET NON-ZERO IN MPAC
051258,000053: 13,2411 01743 LUNAFLAG # 0=EARTH, 1=MOON
051259,000054: 13,2412 26413 CALLRTRP
051260,000055: 13,2413 77624 CALLRTRP CALL
051261,000056: 13,2414 55370 R-TO-RP # RP VECTOR CONVERTED FROM R B-29
051262,000057: 13,2415 77656 UNIT # UNIT RP B-1
051263,000058: 13,2416 36152 STCALL ALPHAV # U2= 1/2 SINL FOR SETRE SUBR BELOW
051264,000059: 13,2417 26601 SETGAMMA # SET GAMMA=B2/A2 FOR EARTH, =1 FOR MOON
051265,000060: 13,2420 77624 CALL # SCALED B-1
051266,000061: 13,2421 26611 SETRE # CALC RE METERS B-29
051267,000062: 13,2422 63545 DLOAD DSQ
051268,000063: 13,2423 02152 ALPHAV
051269,000064: 13,2424 63525 PDDL DSQ
051270,000065: 13,2425 02154 ALPHAV +2
051271,000066: 13,2426 75415 DAD SQRT
051272,000067: 13,2427 76405 DMP SL1R
051273,000068: 13,2430 00011 GAMRP
051274,000069: 13,2431 14021 STODL COSTH # COS(LAT) B-1
051275,000070: 13,2432 02156 ALPHAV +4
051276,000071: 13,2433 34023 STCALL SINTH # SIN(LAT) B-1
051277,000072: 13,2434 26541 ARCTAN
051278,000073: 13,2435 15104 STODL LAT # LAT B0
051279,000074: 13,2436 02152 ALPHAV
051280,000075: 13,2437 14021 STODL COSTH # COS(LONG) B-1
051281,000076: 13,2440 02154 ALPHAV +2
051282,000077: 13,2441 34023 STCALL SINTH # SIN(LONG) B-1
051283,000078: 13,2442 26541 ARCTAN
051284,000079: 13,2443 15106 STODL LONG # LONG. REVS B-0 IN RANGE -1/2 TO 1/2
051285,000080: 13,2444 02310 ALPHAM
051286,000081: 13,2445 77625 DSU # ALT= R-RE METERS B-29
051287,000082: 13,2446 02241 ERADM
051288,000083: 13,2447 35110 STCALL ALT # EXIT WITH ALT METERS B-29
051289,000084: 13,2450 02242 INCORPEX
051290,000085: # SUBROUTINE TO CONVERT LAT,LONG,ALT AT GIVEN TIME TO RADIUS VECTOR
051291,000086:
051292,000087: # CALLING SEQUENCE
051293,000088: # L-1 CALL
051294,000089: # L LALOTORV
051295,000090:
051296,000091: # SUBROUTINES USED
051297,000092: # SETGAMMA, SETRE, RP-TO-R
051298,000093:
051299,000094: # ERASABLE INIT. REQ.
051300,000095: # AXO, AYO, AZO, TEPHEM SET AT LAUNCH TIME
051301,000096: # LAT -- LATITUDE (REVS B0)
051302,000097: # LONG -- LONGITUDE (REVS B0)
051303,000098: # ALT -- ALTITUDE (METERS) B-29
051304,000099: # MPAC -- TIME (CSECS B-28)
051305,000100: # ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
051306,000101: # LUNAFLAG=0 FOR EARTH, 1 FOR MOON
051307,000102:
051308,000103: # OUTPUT
051309,000104: # R-VECTOR IN ALPHAV (METERS B-29)
051310,000105:
051311,000106: 13,2451 40220 LALOTORV STQ SETPD # LAT,LONG,ALT TO R VECTOR
051312,000107: 13,2452 02242 INCORPEX
051313,000108: 13,2453 00001 0D
051314,000109: 13,2454 34007 STCALL 6D # 6-7D = TIME FOR RP-TO-R
051315,000110: 13,2455 26601 SETGAMMA # GAMMA = B2/A2 FOR EARTH, 1 FOR MOON B-1
051316,000111: 13,2456 73545 DLOAD SIN # COS(LONG)COS(LAT) IN MPAC
051317,000112: 13,2457 01104 LAT # UNIT RP = SIN(LONG)COS(LAT) 2-3D
051318,000113: 13,2460 65275 DMPR PDDL # PD 2 GAMMA*SIN(LAT) 0-1D
051319,000114: 13,2461 00011 GAMRP
051320,000115: 13,2462 01104 LAT # 0-1D = GAMMA*SIN(LAT) B-2
051321,000116: 13,2463 65346 COS PDDL # PD4 2-3D= COS(LAT) B-1 TEMPORARILY
051322,000117: 13,2464 01106 LONG
051323,000118: 13,2465 57356 SIN DMPR # PD 2
051324,000119: 13,2466 71525 PDDL COS # PD 4 2-3D= SIN(LONG)COS(LAT) B-2
051325,000120: 13,2467 01104 LAT
051326,000121: 13,2470 71525 PDDL COS # PD 6 4-5D= COS(LAT) B-1 TEMPORARILY
051327,000122: 13,2471 01106 LONG
051328,000123: 13,2472 55475 DMPR VDEF # PD4 MPAC = COS(LONG)COS(LAT) B-2
051329,000124: 13,2473 41456 UNIT PUSH # 0-5D = UNIT RP FOR RP-TO-R SUBR.
051330,000125: 13,2474 36152 STCALL ALPHAV # ALPHAV +4= SINL FOR SETRE SUBR.
051331,000126: 13,2475 26611 SETRE # RE METERS B-29
051332,000127: 13,2476 43145 DLOAD BOFF # SET MPAC = 0 FOR EARTH, NON-ZERO FOR MOON
051333,000128: 13,2477 11566 ZEROVEC
051334,000129: 13,2500 01743 LUNAFLAG
051335,000130: 13,2501 26503 CALLRPRT
051336,000131: 13,2502 77746 COS # USE COS(0) TO GET NON-ZERO IN MPAC
051337,000132: 13,2503 77624 CALLRPRT CALL
051338,000133: 13,2504 55343 RP-TO-R # EXIT WITH UNIT R VECTOR IN MPAC
051339,000134: 13,2505 16152 STODL ALPHAV
051340,000135: 13,2506 02241 ERADM
051341,000136: 13,2507 74215 DAD VXSC # (RE + ALT)(UNIT R) METERS B-30
051342,000137: 13,2510 01110 ALT
051343,000138: 13,2511 02152 ALPHAV
051344,000139: 13,2512 77772 VSL1 # R METERS B-29
051345,000140: 13,2513 36152 STCALL ALPHAV # EXIT WITH R IN METERS B-29
051346,000141: 13,2514 02242 INCORPEX
051347,000142:
051348,000143: # SUBROUTINE TO COMPUTE EARTH RADIUS
051349,000144:
051350,000145: # INPUT
051351,000146: # 1/2 SIN LAT IN ALPHAV +4
051352,000147:
051353,000148: # OUTPUT
051354,000149: # EARTH RADIUS IN ERADM AND MPAC (METERS B-29)
051355,000150:
051356,000151: 13,2515 63545 GETERAD DLOAD DSQ
051357,000152: 13,2516 02156 ALPHAV +4 # SIN**2(L)
051358,000153: 13,2517 44352 SL1 BDSU
051359,000154: 13,2520 11564 DP1/2 # COS**2(L)
051360,000155: 13,2521 44275 DMPR BDSU
051361,000156: 13,2522 26536 EE
051362,000157: 13,2523 11564 DP1/2
051363,000158: 13,2524 75465 BDDV SQRT
051364,000159: 13,2525 26532 B2XSC
051365,000160: 13,2526 77622 SR4R
051366,000161: 13,2527 02241 STORE ERADM
051367,000162: 13,2530 77616 RVQ
051368,000163:
051369,000164: # THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166, B=6356784 METERS
051370,000165: # B2XSC = B**2 SCALED B-51
051371,000166: # B2/A2 = B**2/A**2 SCALED B-1
051372,000167: # EE = (1-B**2/A**2) SCALED B-0
051373,000168:
051374,000169: 13,2531 00446 00305 B2XSC 2DEC .0179450689 # B**2 SCALED B-51
051375,000170:
051376,000171: 13,2533 04,3563 DP1/2 = XUNIT
051377,000172: 13,2533 17711 05254 B2/A2 2DEC .9933064884 B-1 # GAMMA= B**2/A**2 B-1
051378,000173:
051379,000174: 13,2535 00155 25250 EE 2DEC 6.6935116 E-3 # (1-B**2/A**2) B-0
051380,000175:
051381,000176: 13,2537 00302 17755 ERAD 2DEC 6373338 B-29 # PAD RADIUS
051382,000177:
051383,000178: # ARCTAN SUBROUTINE
051384,000179:
051385,000180: # CALLING SEQUENCE
051386,000181: # SIN THETA IN SINTH B-1
051387,000182: # COS THETA IN COSTH B-1
051388,000183: # CALL ARCTAN
051389,000184:
051390,000185: # OUTPUT
051391,000186: # ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
051392,000187:
051393,000188: 13,2541 77600 ARCTAN BOV
051394,000189: 13,2542 26543 CLROVFLW
051395,000190: 13,2543 63545 CLROVFLW DLOAD DSQ
051396,000191: 13,2544 00023 SINTH
051397,000192: 13,2545 63525 PDDL DSQ
051398,000193: 13,2546 00021 COSTH
051399,000194: 13,2547 77615 DAD
051400,000195: 13,2550 75454 BZE SQRT
051401,000196: 13,2551 26567 ARCTANXX # ATAN=0/0 SET THETA=0
051402,000197: 13,2552 40065 BDDV BOV
051403,000198: 13,2553 00023 SINTH
051404,000199: 13,2554 26574 ATAN=90
051405,000200: 13,2555 67542 SR1 ASIN
051406,000201: 13,2556 00025 STORE THETA
051407,000202: 13,2557 50125 PDDL BMN
051408,000203: 13,2560 00021 COSTH
051409,000204: 13,2561 26563 NEGCOS
051410,000205: 13,2562 43545 DLOAD RVQ
051411,000206: 13,2563 57545 NEGCOS DLOAD DCOMP
051412,000207: 13,2564 43244 BPL DAD
051413,000208: 13,2565 26571 NEGOUT
051414,000209: 13,2566 11564 DP1/2
051415,000210: 13,2567 00025 ARCTANXX STORE THETA
051416,000211: 13,2570 77616 RVQ
051417,000212:
051418,000213: 13,2571 52025 NEGOUT DSU GOTO
051419,000214: 13,2572 11564 DP1/2
051420,000215: 13,2573 26567 ARCTANXX
051421,000216: 13,2574 75345 ATAN=90 DLOAD SIGN
051422,000217: 13,2575 11612 LODP1/4
051423,000218: 13,2576 00023 SINTH
051424,000219: 13,2577 00025 STORE THETA
051425,000220: 13,2600 77616 RVQ
051426,000221:
051427,000222: 13,2601 04,3565 2DZERO = DPZERO
051428,000223:
051429,000224: # ..... SETGAMMA SUBROUTINE .....
051430,000225: # SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
051431,000226:
051432,000227: # GAMMA = B**2/A**2 FOR EARTH (B-1)
051433,000228: # GAMMA = 1 FOR MOON (B-1)
051434,000229:
051435,000230: # CALLING SEQUENCE
051436,000231: # L CALL
051437,000232: # L+1 SETGAMMA
051438,000233:
051439,000234: # INPUT
051440,000235: # LUNAFLAG=0 FOR EARTH, =1 FOR MOON
051441,000236:
051442,000237: # OUTPUT
051443,000238: # GAMMA IN GAMRP (B-1)
051444,000239:
051445,000240: 13,2601 43145 SETGAMMA DLOAD BOFF # BRANCH FOR EARTH
051446,000241: 13,2602 26534 B2/A2 # EARTH GAMMA
051447,000242: 13,2603 01743 LUNAFLAG
051448,000243: 13,2604 26607 SETGMEX
051449,000244: 13,2605 77735 SLOAD
051450,000245: 13,2606 11564 1B1 # MOON GAMMA
051451,000246: 13,2607 00011 SETGMEX STORE GAMRP
051452,000247: 13,2610 77616 RVQ
051453,000248: 13,2611 GAMRP = 8D
051454,000249:
051455,000250: # ..... SETRE SUBROUTINE .....
051456,000251: # SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
051457,000252:
051458,000253: # RE = RM FOR MOON
051459,000254: # RE = RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
051460,000255:
051461,000256: # CALLING SEQUENCE
051462,000257: # L CALL
051463,000258: # L+1 SETRE
051464,000259:
051465,000260: # SUBROUTINES USED
051466,000261: # GETERAD
051467,000262:
051468,000263: # INPUT
051469,000264: # ERADFLAG = 0 FOR FIXED RE, 1 FOR COMPUTED RE
051470,000265: # ALPHAV +4 = 1/2 SINL IF GETERAD IS CALLED
051471,000266: # LUNAFLAG = 0 FOR EARTH, =1 FOR MOON
051472,000267:
051473,000268: # OUTPUT
051474,000269: # ERADM = 504RM FOR MOON (METERS B-29)
051475,000270: # ERADM = ERAD OR COMPUTED RF FOR EARTH (METERS B-29)
051476,000271:
051477,000272: 13,2611 71220 SETRE STQ DLOAD
051478,000273: 13,2612 00051 SETREX
051479,000274: 13,2613 26636 504RM
051480,000275: 13,2614 71214 BON DLOAD # BRANCH FOR MOON
051481,000276: 13,2615 01703 LUNAFLAG
051482,000277: 13,2616 26626 TSTRLSRM
051483,000278: 13,2617 26540 ERAD
051484,000279: 13,2620 45014 BOFF CALL # ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED
051485,000280: 13,2621 00742 ERADFLAG
051486,000281: 13,2622 26624 SETRXX
051487,000282: 13,2623 26515 GETERAD
051488,000283: 13,2624 36241 SETRXX STCALL ERADM # EXIT WITH RE OR RM METERS B-29
051489,000284: 13,2625 00051 SETREX
051490,000285: 13,2626 77214 TSTRLSRM BON VLOAD # ERADFLAG=0, SET R0=RLS
051491,000286: 13,2627 00702 ERADFLAG # =1 R0=RM
051492,000287: 13,2630 26624 SETRXX
051493,000288: 13,2631 02026 RLS
051494,000289: 13,2632 64446 ABVAL SR2R # SCALE FROM B-27 TO B-29
051495,000290: 13,2633 77650 GOTO
051496,000291: 13,2634 26624 SETRXX
051497,000292: 13,2635 0000051 SETREX = S2
051498,000293: 13,2635 00065 01265 504RM 2DEC 1738090 B-29 # METERS B-29 (MOON RADIUS)
051499,000294:
051500,000295:
051501,000296:
051502,000297:
End of include-file LATITUDE_LONGITUDE_SUBROUTINES.agc. Parent file is MAIN.agc