Notations on the program listing read, in part:
GAP: ASSEMBLE REVISION 210 OF AGC PROGRAM LUMINARY BY NASA 2021112-161 17:11 MAR. 19,1971Note that the date is the date of the printout, not the date of the program revision.
Source Code
|
|
These source-code files derive from a printout of Luminary 210 (Apollo 15-17
Lunar Module guidance computer program), from the personal library of
original AGC developer Don Eyles, digitally photographed at archive.org,
financially sponsored by Jim Lawton, 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 210 OF AGC PROGRAM LUMINARY BY NASA 2021112-161 17:11 MAR. 19,1971Note that the date is the date of the printout, not the date of the program revision. |
048552,000002: ## Copyright: Public domain.
048553,000003: ## Filename: LATITUDE_LONGITUDE_SUBROUTINES.agc
048554,000004: ## Purpose: A section of Luminary revision 210.
048555,000005: ## It is part of the source code for the Lunar Module's (LM)
048556,000006: ## Apollo Guidance Computer (AGC) for Apollo 15-17.
048557,000007: ## This file is intended to be a faithful transcription, except
048558,000008: ## that the code format has been changed to conform to the
048559,000009: ## requirements of the yaYUL assembler rather than the
048560,000010: ## original YUL assembler.
048561,000011: ## Reference: pp. 1131-1137
048562,000012: ## Assembler: yaYUL
048563,000013: ## Contact: Ron Burkey <info@sandroid.org>.
048564,000014: ## Website: www.ibiblio.org/apollo/index.html
048565,000015: ## Mod history: 2016-11-17 JL Created from Luminary131 version.
048566,000016: ## 2016-12-12 MAS Transcribed.
048567,000017: ## 2016-12-26 RSB Comment-text proofed using ProoferComments
048568,000018: ## and corrected errors found.
048569,000019:
|
|
Page 1131 |
048571,000021: # SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
048572,000022:
048573,000023: # CALLING SEQUENCE
048574,000024:
048575,000025: # L-1 CALL
048576,000026: # L LAT-LONG
048577,000027: # SUBROUTINES USED
048578,000028:
048579,000029: # R-TO-RP,ARCTAN,SETGAMMA,SETRE
048580,000030: # ERASABLE INIT. REQ.
048581,000031:
048582,000032: # AXO,-AYO,AZO,TEPHEM (SET AT LAUNCH TIME)
048583,000033: # ALPHAV = POSITION VECTOR METERS B-29
048584,000034: # MPAC-- TIME (CSECS B-28)
048585,000035: # ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
048586,000036: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
048587,000037: # OUTPUT
048588,000038:
048589,000039: # LATITUDE IN LAT (REVS. B-0)
048590,000040: # LONGITUDE IN LONG (REVS. B-0)
048591,000041: # ALTITUDE IN ALT METERS B-29
048592,000042: 30,3761 BANK 30
048593,000043: 13,2000 SETLOC LATLONG
048594,000044: 13,2000 BANK
048595,000045:
048596,000046: 13,2406 COUNT* $$/LT-LG
048597,000047: 13,2406 E4,1431 EBANK= ALPHAV
048598,000048: 13,2406 40220 LAT-LONG STQ SETPD
048599,000049: 13,2407 03674 INCORPEX
048600,000050: 13,2410 00001 0D
048601,000051: 13,2411 24007 STOVL 6D # SAVE TIME IN 6-7D FOR R-TO-RP
048602,000052: 13,2412 02032 ALPHAV
048603,000053: 13,2413 51406 PUSH ABVAL # 0-5D= R FOR R-TO-RP
048604,000054: 13,2414 16070 STODL ALPHAM # ABS. VALUE OF R FOR ALT FORMULA BELOW
048605,000055: 13,2415 24007 ZEROVEC # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
048606,000056: 13,2416 71414 BOFF COS # USE COS(0) TO GET NON-ZERO IN MPAC
048607,000057: 13,2417 01743 LUNAFLAG # 0=EARTH,1=MOON
048608,000058: 13,2420 26421 CALLRTRP
048609,000059: 13,2421 77624 CALLRTRP CALL
048610,000060: 13,2422 51644 R-TO-RP # RP VECTOR CONVERTED FROM R B-29
048611,000061: 13,2423 77656 UNIT # UNIT RP B-1
048612,000062: 13,2424 36032 STCALL ALPHAV # U2= 1/2 SINL FOR SETRE SUBR BELOW
048613,000063: 13,2425 26605 SETGAMMA # SET GAMMA=B2/A2 FOR EARTH,=1 FOR MOON
048614,000064: 13,2426 77624 CALL # SCALED B-1
048615,000065: 13,2427 26615 SETRE # CALC RE METERS B-29
048616,000066: 13,2430 63545 DLOAD DSQ
048617,000067: 13,2431 02032 ALPHAV
048618,000068: 13,2432 63525 PDDL DSQ
048619,000069: 13,2433 02034 ALPHAV +2
048620,000070: 13,2434 75415 DAD SQRT
|
|
Page 1132 |
048622,000072: 13,2435 76405 DMP SL1R
048623,000073: 13,2436 00011 GAMRP
048624,000074: 13,2437 14021 STODL COSTH # COS(LAT) B-1
048625,000075: 13,2440 02036 ALPHAV +4
048626,000076: 13,2441 34023 STCALL SINTH # SIN(LAT) B-1
048627,000077: 13,2442 26545 ARCTAN
048628,000078: 13,2443 15120 STODL LAT # LAT B0
048629,000079: 13,2444 02032 ALPHAV
048630,000080: 13,2445 14021 STODL COSTH # COS(LONG) B-1
048631,000081: 13,2446 02034 ALPHAV +2
048632,000082: 13,2447 34023 STCALL SINTH # SIN(LONG) B-1
048633,000083: 13,2450 26545 ARCTAN
048634,000084: 13,2451 15122 STODL LONG # LONG. REVS B-0 IN RANGE -1/2 TO 1/2
048635,000085: 13,2452 02070 ALPHAM
048636,000086: 13,2453 77625 DSU # ALT= R-RE METERS B-29
048637,000087: 13,2454 03673 ERADM
048638,000088: 13,2455 35124 STCALL ALT # EXIT WITH ALT METERS B-29
048639,000089: 13,2456 03674 INCORPEX
|
|
Page 1133 |
048641,000091: # SUBROUTINE TO CONVERT LAT,LONG,ALT AT GIVEN TIME TO RADIUS VECTOR
048642,000092: # CALLING SEQUENCE
048643,000093:
048644,000094: # L-1 CALL
048645,000095: # L LALOTORV
048646,000096: # SUBROUTINES USED
048647,000097:
048648,000098: # SETGAMMA,SETRE,RP-TO-R
048649,000099: # ERASABLE INIT. REQ.
048650,000100:
048651,000101: # AXO,AYO,AZO,TEPHEM SET AT LAUNCH TIME
048652,000102: # LAT-- LATITUDE (REVS B0)
048653,000103: # LONG-- LONGITUDE (REVS B0)
048654,000104: # ALT--ALTITUDE (METERS) B-29
048655,000105: # MPAC-- TIME (CSECS B-28)
048656,000106: # ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
048657,000107: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
048658,000108: # OUTPUT
048659,000109:
048660,000110: # R-VECTOR IN ALPHAV (METERS B-29)
048661,000111: 13,2457 40220 LALOTORV STQ SETPD # LAT,LONG,ALT TO R VECTOR
048662,000112: 13,2460 03674 INCORPEX
048663,000113: 13,2461 00001 0D
048664,000114: 13,2462 34007 STCALL 6D # 6-7D= TIME FOR RP-TO-R
048665,000115: 13,2463 26605 SETGAMMA # GAMMA=B2/A2 FOR EARTH,1 FOR MOON B-1
048666,000116: 13,2464 73545 DLOAD SIN # COS(LONG)COS(LAT) IN MPAC
048667,000117: 13,2465 01120 LAT # UNIT RP= SIN(LONG)COS(LAT) 2-3D
048668,000118: 13,2466 65275 DMPR PDDL # PD 2 GAMMA*SIN(LAT) 0-1D
048669,000119: 13,2467 00011 GAMRP
048670,000120: 13,2470 01120 LAT # 0-1D= GAMMA*SIN(LAT) B-2
048671,000121: 13,2471 65346 COS PDDL # PD4 2-3D=COS(LAT) B-1 TEMPORARILY
048672,000122: 13,2472 01122 LONG
048673,000123: 13,2473 57356 SIN DMPR # PD 2
048674,000124: 13,2474 71525 PDDL COS # PD 4 2-3D=SIN(LONG)COS(LAT) B-2
048675,000125: 13,2475 01120 LAT
048676,000126: 13,2476 71525 PDDL COS # PD 6 4-5D=COS(LAT) B-1 TEMPORARILY
048677,000127: 13,2477 01122 LONG
048678,000128: 13,2500 55475 DMPR VDEF # PD 4 MPAC= COS(LONG)COS(LAT) B-2
048679,000129: 13,2501 41456 UNIT PUSH # 0-5D= UNIT RP FOR RP-TO-R SUBR.
048680,000130: 13,2502 36032 STCALL ALPHAV # ALPHAV +4= SINL FOR SETRE SUBR.
048681,000131: 13,2503 26615 SETRE # RE METERS B-29
048682,000132: 13,2504 43145 DLOAD BOFF # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
048683,000133: 13,2505 24007 ZEROVEC
048684,000134: 13,2506 01743 LUNAFLAG
048685,000135: 13,2507 26511 CALLRPRT
048686,000136: 13,2510 77746 COS # USE COS(0) TO GET NON-ZERO IN MPAC
048687,000137: 13,2511 77624 CALLRPRT CALL
048688,000138: 13,2512 55716 RP-TO-R # EXIT WITH UNIT R VECTOR IN MPAC
048689,000139: 13,2513 16032 STODL ALPHAV
048690,000140: 13,2514 03673 ERADM
|
|
Page 1134 |
048692,000142: 13,2515 74215 DAD VXSC # (RE + ALT)(UNIT R) METERS B-30
048693,000143: 13,2516 01124 ALT
048694,000144: 13,2517 02032 ALPHAV
048695,000145: 13,2520 77772 VSL1 # R METERS B-29
048696,000146: 13,2521 36032 STCALL ALPHAV # EXIT WITH R IN METERS B-29
048697,000147: 13,2522 03674 INCORPEX
048698,000148: # SUBROUTINE TO COMPUTE EARTH RADIUS
048699,000149:
048700,000150: # INPUT
048701,000151:
048702,000152: # 1/2 SIN LAT IN ALPHAV +4
048703,000153:
048704,000154: # OUTPUT
048705,000155:
048706,000156: # EARTH RADIUS IN ERADM AND MPAC (METERS B-29)
048707,000157:
048708,000158: 13,2523 63545 GETERAD DLOAD DSQ
048709,000159: 13,2524 02036 ALPHAV +4 # SIN**2(L)
048710,000160: 13,2525 44352 SL1 BDSU
048711,000161: 13,2526 24005 DP1/2 # COS**2(L)
048712,000162: 13,2527 44275 DMPR BDSU
048713,000163: 13,2530 26544 EE
048714,000164: 13,2531 24005 DP1/2
048715,000165: 13,2532 75465 BDDV SQRT
048716,000166: 13,2533 26540 B2XSC
048717,000167: 13,2534 77622 SR4R
048718,000168: 13,2535 03673 STORE ERADM
048719,000169: 13,2536 77616 RVQ
048720,000170:
048721,000171: # THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166,B=6356784 METERS
048722,000172: # B2XSC= B**2 SCALED B-51
048723,000173: # B2/A2= B**2/A**2 SCALED B-1
048724,000174: # EE=(1-B**2/A**2) SCALED B-0
048725,000175: 13,2537 00446 00305 B2XSC 2DEC .0179450689 # B**2 SCALED B-51
048726,000176:
048727,000177: 13,2541 12,2004 DP1/2 = XUNIT
048728,000178: 13,2541 17711 05254 B2/A2 2DEC .9933064884 B-1 # GAMMA= B**2/A**2 B-1
048729,000179:
048730,000180: 13,2543 00155 25250 EE 2DEC 6.6935116 E-3 # (1-B**2/A**2) B-0
048731,000181:
|
|
Page 1135 |
048733,000183: # ARCTAN SUBROUTINE
048734,000184:
048735,000185:
048736,000186: # CALLING SEQUENCE
048737,000187:
048738,000188: # SIN THETA IN SINTH B-1
048739,000189: # COS THETA IN COSTH B-1
048740,000190: # CALL ARCTAN
048741,000191:
048742,000192: # OUTPUT
048743,000193: # ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
048744,000194:
048745,000195:
048746,000196: 13,2545 77600 ARCTAN BOV
048747,000197: 13,2546 26547 CLROVFLW
048748,000198: 13,2547 63545 CLROVFLW DLOAD DSQ
048749,000199: 13,2550 00023 SINTH
048750,000200: 13,2551 63525 PDDL DSQ
048751,000201: 13,2552 00021 COSTH
048752,000202: 13,2553 77615 DAD
048753,000203: 13,2554 75454 BZE SQRT
048754,000204: 13,2555 26573 ARCTANXX # ATAN=0/0 SET THETA=0
048755,000205: 13,2556 40065 BDDV BOV
048756,000206: 13,2557 00023 SINTH
048757,000207: 13,2560 26600 ATAN=90
048758,000208: 13,2561 67542 SR1 ASIN
048759,000209: 13,2562 00025 STORE THETA
048760,000210: 13,2563 50125 PDDL BMN
048761,000211: 13,2564 00021 COSTH
048762,000212: 13,2565 26567 NEGCOS
048763,000213: 13,2566 43545 DLOAD RVQ
048764,000214: 13,2567 57545 NEGCOS DLOAD DCOMP
048765,000215: 13,2570 43244 BPL DAD
048766,000216: 13,2571 26575 NEGOUT
048767,000217: 13,2572 24005 DP1/2
048768,000218: 13,2573 00025 ARCTANXX STORE THETA
048769,000219: 13,2574 77616 RVQ
048770,000220:
048771,000221: 13,2575 52025 NEGOUT DSU GOTO
048772,000222: 13,2576 24005 DP1/2
048773,000223: 13,2577 26573 ARCTANXX
048774,000224: 13,2600 75345 ATAN=90 DLOAD SIGN
048775,000225: 13,2601 11040 LODP1/4
048776,000226: 13,2602 00023 SINTH
048777,000227: 13,2603 00025 STORE THETA
048778,000228: 13,2604 77616 RVQ
048779,000229:
048780,000230: 13,2605 12,2006 2DZERO = DPZERO
048781,000231:
|
|
Page 1136 |
048783,000233: # ..... SETGAMMA SUBROUTINE .....
048784,000234: # SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
048785,000235:
048786,000236: # GAMMA = B**2/A**2 FOR EARTH (B-1)
048787,000237: # GAMMA = 1 FOR MOON (B-1)
048788,000238:
048789,000239: # CALLING SEQUENCE
048790,000240: # L CALL
048791,000241: # L+1 SETGAMMA
048792,000242:
048793,000243: # INPUT
048794,000244: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
048795,000245:
048796,000246: # OUTPUT
048797,000247: # GAMMA IN GAMRP (B-1)
048798,000248:
048799,000249: 13,2605 43145 SETGAMMA DLOAD BOFF # BRANCH FOR EARTH
048800,000250: 13,2606 26542 B2/A2 # EARTH GAMMA
048801,000251: 13,2607 01743 LUNAFLAG
048802,000252: 13,2610 26613 SETGMEX
048803,000253: 13,2611 77735 SLOAD
048804,000254: 13,2612 24005 1B1 # MOON GAMMA
048805,000255: 13,2613 00011 SETGMEX STORE GAMRP
048806,000256: 13,2614 77616 RVQ
048807,000257: 13,2615 GAMRP = 8D
048808,000258:
|
|
Page 1137 |
048810,000260: # .....SETRE SUBROUTINE .....
048811,000261: # SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
048812,000262:
048813,000263: # RE= RM FOR MOON
048814,000264: # RE= RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
048815,000265:
048816,000266: # CALLING SEQUENCE
048817,000267: # L CALL
048818,000268: # L+1 SETRE
048819,000269:
048820,000270: # SUBROUTINES USED
048821,000271: # GETERAD
048822,000272:
048823,000273: # INPUT
048824,000274: # ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED RE
048825,000275: # ALPHAV +4= 1/2 SINL IF GETERAD IS CALLED
048826,000276: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
048827,000277:
048828,000278: # OUTPUT
048829,000279: # ERADM= 504RM FOR MOON (METERS B-29)
048830,000280: # ERADM= ERAD OR COMPUTED RF FOR EARTH (METERS B-29)
048831,000281:
048832,000282: 13,2615 71220 SETRE STQ DLOAD
048833,000283: 13,2616 00051 SETREX
048834,000284: 13,2617 10003 504RM
048835,000285: 13,2620 71214 BON DLOAD # BRANCH FOR MOON
048836,000286: 13,2621 01703 LUNAFLAG
048837,000287: 13,2622 26632 TSTRLSRM
048838,000288: 13,2623 10001 ERAD
048839,000289: 13,2624 45014 BOFF CALL # ERADFLAG=0 FOR FIXED RE,1 FOR COMPUTED
048840,000290: 13,2625 00742 ERADFLAG
048841,000291: 13,2626 26630 SETRXX
048842,000292: 13,2627 26523 GETERAD
048843,000293: 13,2630 37673 SETRXX STCALL ERADM # EXIT WITH RE OR RM METERS B-29
048844,000294: 13,2631 00051 SETREX
048845,000295: 13,2632 77214 TSTRLSRM BON VLOAD # ERADFLAG=0,SET R0=RLS
048846,000296: 13,2633 00702 ERADFLAG # =1 R0=RM
048847,000297: 13,2634 26630 SETRXX
048848,000298: 13,2635 02021 RLS
048849,000299: 13,2636 64446 ABVAL SR2R # SCALE FROM B-27 TO B-29
048850,000300: 13,2637 77650 GOTO
048851,000301: 13,2640 26630 SETRXX
048852,000302: 13,2641 0000051 SETREX = S2
End of include-file LATITUDE_LONGITUDE_SUBROUTINES.agc. Parent file is MAIN.agc