Source Code
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These source-code files were obtained by digitally photographing the
Colossus 237 program listing from the private collection of original
AGC developer Fred Martin, and then modifying pre-existing Colossus 249
(Apollo 9) source files to incorporate changes. Note that the page images
presented online are of reduced quality, and that additional images
are available. Report any conversion errors or legibility
problems in page images to info@sandroid.org.
Notations on the program listing read, in part:GAP: ASSEMBLE REVISION 237 OF AGC PROGRAM COLOSSUS BY NASA 2021111-031 1:17 AUG. 24, 1968 |
050773,000002: # Copyright: Public domain.
050774,000003: # Filename: LATITUDE_LONGITUDE_SUBROUTINES.agc
050775,000004: # Purpose: Part of the source code for Colossus build 237.
050776,000005: # This is for the Command Module's (CM) Apollo Guidance
050777,000006: # Computer (AGC), we believe for Apollo 8.
050778,000007: # Assembler: yaYUL
050779,000008: # Contact: Jim Lawton <jim DOT lawton AT gmail DOT com>
050780,000009: # Website: www.ibiblio.org/apollo/index.html
050781,000010: # Page scans: www.ibiblio.org/apollo/ScansForConversion/Colossus237/
050782,000011: # Mod history: 2011-04-13 JL Adapted from corresponding Colossus 249 file.
050783,000012:
050784,000013: # # Page 1203
050785,000014: # SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
050786,000015:
050787,000016: # CALLING SEQUENCE
050788,000017:
050789,000018: # L-1 CALL
050790,000019: # L LAT-LONG
050791,000020: # SUBROUTINES USED
050792,000021:
050793,000022: # R-TO-RP,ARCTAN,SETGAMMA,SETRE
050794,000023: # ERASABLE INIT. REQ.
050795,000024:
050796,000025: # AXO,-AYO,AZO,TEPHEM (SET AT LAUNCH TIME)
050797,000026: # ALPHAV = POSITION VECTOR METERS B-29
050798,000027: # MPAC-- TIME (CSECS B-28)
050799,000028: # ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
050800,000029: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
050801,000030: # OUTPUT
050802,000031:
050803,000032: # LATITUDE IN LAT (REVS. B-0)
050804,000033: # LONGITUDE IN LONG (REVS. B-0)
050805,000034: # ALTITUDE IN ALT METERS B-29
050806,000035: 30,3776 BANK 30
050807,000036: 13,2000 SETLOC LATLONG
050808,000037: 13,2000 BANK
050809,000038:
050810,000039: 13,2322 COUNT 13/LT-LG
050811,000040:
050812,000041: 13,2322 E4,1551 EBANK= ALPHAV
050813,000042: 13,2322 40220 LAT-LONG STQ SETPD
050814,000043: 13,2323 02242 INCORPEX
050815,000044: 13,2324 00001 0D
050816,000045: 13,2325 24007 STOVL 6D # SAVE TIME IN 6-7D FOR R-TO-RP
050817,000046: 13,2326 02152 ALPHAV
050818,000047: 13,2327 51406 PUSH ABVAL # 0-5D= R FOR R-TO-RP
050819,000048: 13,2330 16310 STODL ALPHAM # ABS. VALUE OF R FOR ALT FORMULA BELOW
050820,000049: 13,2331 11453 ZEROVEC # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
050821,000050: 13,2332 71414 BOFF COS # USE COS(0) TO GET NON-ZERO IN MPAC
050822,000051: 13,2333 01743 LUNAFLAG # 0=EARTH,1=MOON
050823,000052: 13,2334 26335 CALLRTRP
050824,000053: 13,2335 77624 CALLRTRP CALL
050825,000054: 13,2336 55366 R-TO-RP # RP VECTOR CONVERTED FROM R B-29
050826,000055: 13,2337 77656 UNIT # UNIT RP B-1
050827,000056: 13,2340 36152 STCALL ALPHAV # U2= 1/2 SINL FOR SETRE SUBR BELOW
050828,000057: 13,2341 26523 SETGAMMA # SET GAMMA=B2/A2 FOR EARTH,=1 FOR MOON
050829,000058: 13,2342 77624 CALL # SCALED B-1
050830,000059: 13,2343 26533 SETRE # CALC RE METERS B-29
050831,000060: 13,2344 63545 DLOAD DSQ
050832,000061: 13,2345 02152 ALPHAV
050833,000062: 13,2346 63525 PDDL DSQ
050834,000063: 13,2347 02154 ALPHAV +2
050835,000064: # # Page 1204
050836,000065: 13,2350 75415 DAD SQRT
050837,000066: 13,2351 76405 DMP SL1R
050838,000067: 13,2352 00011 GAMRP
050839,000068: 13,2353 14021 STODL COSTH # COS(LAT) B-1
050840,000069: 13,2354 02156 ALPHAV +4
050841,000070: 13,2355 34023 STCALL SINTH # SIN(LAT) B-1
050842,000071: 13,2356 26463 ARCTAN
050843,000072: 13,2357 15104 STODL LAT # LAT B0
050844,000073: 13,2360 02152 ALPHAV
050845,000074: 13,2361 14021 STODL COSTH # COS(LONG) B-1
050846,000075: 13,2362 02154 ALPHAV +2
050847,000076: 13,2363 34023 STCALL SINTH # SIN(LONG) B-1
050848,000077: 13,2364 26463 ARCTAN
050849,000078: 13,2365 15106 STODL LONG # LONG. REVS B-0 IN RANGE -1/2 TO 1/2
050850,000079: 13,2366 02310 ALPHAM
050851,000080: 13,2367 77625 DSU # ALT= R-RE METERS B-29
050852,000081: 13,2370 02241 ERADM
050853,000082: 13,2371 35110 STCALL ALT # EXIT WITH ALT METERS B-29
050854,000083: 13,2372 02242 INCORPEX
050855,000084:
050856,000085: # # Page 1205
050857,000086: # SUBROUTINE TO CONVERT LAT,LONG.ALT AT GIVEN TIME TO RADIUS VECTOR
050858,000087: # CALLING SEQUENCE
050859,000088:
050860,000089: # L-1 CALL
050861,000090: # L LALOTORV
050862,000091: # SUBROUTINES USED
050863,000092:
050864,000093: # SETGAMMA,SETRE,RP-TO-R
050865,000094: # ERASABLE INIT. REQ.
050866,000095:
050867,000096: # AXO,AYO,AZO,TEPHEM SET AT LAUNCH TIME
050868,000097: # LAT-- LATITUDE (REVS B0)
050869,000098: # LONG-- LONGITUDE (REVS B0)
050870,000099: # ALT--ALTITUDE (METERS) B-29
050871,000100: # MPAC-- TIME (CSECS B-28)
050872,000101: # ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
050873,000102: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
050874,000103: # OUTPUT
050875,000104:
050876,000105: # R-VECTOR IN ALPHAV (METERS B-29)
050877,000106: 13,2373 40220 LALOTORV STQ SETPD # LAT,LONG,ALT TO R VECTOR
050878,000107: 13,2374 02242 INCORPEX
050879,000108: 13,2375 00001 0D
050880,000109: 13,2376 34007 STCALL 6D # 6-7D= TIME FOR RP-TO-R
050881,000110: 13,2377 26523 SETGAMMA # GAMMA=B2/A2 FOR EARTH,1 FOR MOON B-1
050882,000111: 13,2400 73545 DLOAD SIN # COS(LONG)COS(LAT) IN MPAC
050883,000112: 13,2401 01104 LAT # UNIT RP= SIN(LONG)COS(LAT) 2-3D
050884,000113: 13,2402 65275 DMPR PDDL # PD 2 GAMMA*SIN(LAT) 0-1D
050885,000114: 13,2403 00011 GAMRP
050886,000115: 13,2404 01104 LAT # 0-1D= GAMMA*SIN(LAT) B-2
050887,000116: 13,2405 65346 COS PDDL # PD 4 2-3D=COS(LAT) B-1 TEMPORARILY
050888,000117: 13,2406 01106 LONG
050889,000118: 13,2407 57356 SIN DMPR # PD 2
050890,000119: 13,2410 71525 PDDL COS # PD 4 2-3D=SIN(LONG)COS(LAT) B-2
050891,000120: 13,2411 01104 LAT
050892,000121: 13,2412 71525 PDDL COS # PD 6 4-5D=COS(LAT) B-1 TEMPORARILY
050893,000122: 13,2413 01106 LONG
050894,000123: 13,2414 55475 DMPR VDEF # PD4 MPAC= COS(LONG)COS(LAT) B-2
050895,000124: 13,2415 41456 UNIT PUSH # 0-5D= UNIT RP FOR RP-TO-R SUBR.
050896,000125: 13,2416 36152 STCALL ALPHAV # ALPHAV +4= SINL FOR SETRE SUBR.
050897,000126: 13,2417 26533 SETRE # RE METERS B-29
050898,000127: 13,2420 43145 DLOAD BOFF # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
050899,000128: 13,2421 11453 ZEROVEC
050900,000129: 13,2422 01743 LUNAFLAG
050901,000130: 13,2423 26425 CALLRPRT
050902,000131: 13,2424 77746 COS # USE COS(0) TO GET NON-ZERO IN MPAC
050903,000132: 13,2425 77624 CALLRPRT CALL
050904,000133: 13,2426 55341 RP-TO-R # EXIT WITH UNIT R VECTOR IN MPAC
050905,000134: 13,2427 16152 STODL ALPHAV
050906,000135: 13,2430 02241 ERADM
050907,000136: # # Page 1206
050908,000137: 13,2431 74215 DAD VXSC # (RE + ALT)(UNIT R) METERS B-30
050909,000138: 13,2432 01110 ALT
050910,000139: 13,2433 02152 ALPHAV
050911,000140: 13,2434 77772 VSL1 # R METERS B-29
050912,000141: 13,2435 36152 STCALL ALPHAV # EXIT WITH R IN METERS B-29
050913,000142: 13,2436 02242 INCORPEX
050914,000143: # SUBROUTINE TO COMPUTE EARTH RADIUS
050915,000144:
050916,000145: # INPUT
050917,000146:
050918,000147: # 1/2 SIN LAT IN ALPHAV +4
050919,000148:
050920,000149: # OUTPUT
050921,000150:
050922,000151: # EARTH RADIUS IN ERADM AND MPAC (METERS B-29)
050923,000152:
050924,000153: 13,2437 63545 GETERAD DLOAD DSQ
050925,000154: 13,2440 02156 ALPHAV +4 # SIN**2(L)
050926,000155: 13,2441 44352 SL1 BDSU
050927,000156: 13,2442 11451 DP1/2 # COS**2(L)
050928,000157: 13,2443 44275 DMPR BDSU
050929,000158: 13,2444 26460 EE
050930,000159: 13,2445 11451 DP1/2
050931,000160: 13,2446 75465 BDDV SQRT
050932,000161: 13,2447 26454 B2XSC
050933,000162: 13,2450 77622 SR4R
050934,000163: 13,2451 02241 STORE ERADM
050935,000164: 13,2452 77616 RVQ
050936,000165:
050937,000166: # THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166,B=6356784 METERS
050938,000167: # B2XSC= B**2 SCALED B-51
050939,000168: # B2/A2= B**2/A**2 SCALED B-1
050940,000169: # EE=(1-B**2/A**2) SCALED B-0
050941,000170:
050942,000171: 13,2453 00446 00305 B2XSC 2DEC .0179450689 # B**2 SCALED B-51
050943,000172: 13,2455 04,3450 DP1/2 = XUNIT
050944,000173: 13,2455 17711 05254 B2/A2 2DEC .9933064884 B-1 # GAMMA= B**2/A**2 B-1
050945,000174: 13,2457 00155 25250 EE 2DEC 6.6935116 E-3 # (1-B**2/A**2) B-0
050946,000175: 13,2461 00302 17755 ERAD 2DEC 6373338 B-29 # PAD RADIUS
050947,000176:
050948,000177: # # Page 1207
050949,000178: # ARCTAN SUBROUTINE
050950,000179:
050951,000180:
050952,000181: # CALLING SEQUENCE
050953,000182:
050954,000183: # SIN THETA IN SINTH B-1
050955,000184: # COS THETA IN COSTH B-1
050956,000185: # CALL ARCTAN
050957,000186:
050958,000187: # OUTPUT
050959,000188: # ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
050960,000189:
050961,000190:
050962,000191: 13,2463 77600 ARCTAN BOV
050963,000192: 13,2464 26465 CLROVFLW
050964,000193: 13,2465 63545 CLROVFLW DLOAD DSQ
050965,000194: 13,2466 00023 SINTH
050966,000195: 13,2467 63525 PDDL DSQ
050967,000196: 13,2470 00021 COSTH
050968,000197: 13,2471 77615 DAD
050969,000198: 13,2472 75454 BZE SQRT
050970,000199: 13,2473 26511 ARCTANXX # ATAN=0/0 SET THETA=0
050971,000200: 13,2474 40065 BDDV BOV
050972,000201: 13,2475 00023 SINTH
050973,000202: 13,2476 26516 ATAN=90
050974,000203: 13,2477 67542 SR1 ASIN
050975,000204: 13,2500 00025 STORE THETA
050976,000205: 13,2501 50125 PDDL BMN
050977,000206: 13,2502 00021 COSTH
050978,000207: 13,2503 26505 NEGCOS
050979,000208: 13,2504 43545 DLOAD RVQ
050980,000209: 13,2505 57545 NEGCOS DLOAD DCOMP
050981,000210: 13,2506 43244 BPL DAD
050982,000211: 13,2507 26513 NEGOUT
050983,000212: 13,2510 11451 DP1/2
050984,000213: 13,2511 00025 ARCTANXX STORE THETA
050985,000214: 13,2512 77616 RVQ
050986,000215:
050987,000216: 13,2513 52025 NEGOUT DSU GOTO
050988,000217: 13,2514 11451 DP1/2
050989,000218: 13,2515 26511 ARCTANXX
050990,000219: 13,2516 75345 ATAN=90 DLOAD SIGN
050991,000220: 13,2517 11477 LODP1/4
050992,000221: 13,2520 00023 SINTH
050993,000222: 13,2521 00025 STORE THETA
050994,000223: 13,2522 77616 RVQ
050995,000224:
050996,000225: 13,2523 04,3452 2DZERO = DPZERO
050997,000226:
050998,000227: # # Page 1208
050999,000228: # ..... SETGAMMA SUBROUTINE .....
051000,000229: # SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
051001,000230:
051002,000231: # GAMMA = B**2/A**2 FOR EARTH (B-1)
051003,000232: # GAMMA = 1 FOR MOON (B-1)
051004,000233:
051005,000234: # CALLING SEQUENCE
051006,000235: # L CALL
051007,000236: # L+1 SETGAMMA
051008,000237:
051009,000238: # INPUT
051010,000239: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
051011,000240:
051012,000241: # OUTPUT
051013,000242: # GAMMA IN GAMRP (B-1)
051014,000243:
051015,000244: 13,2523 43145 SETGAMMA DLOAD BOFF # BRANCH FOR EARTH
051016,000245: 13,2524 26456 B2/A2 # EARTH GAMMA
051017,000246: 13,2525 01743 LUNAFLAG
051018,000247: 13,2526 26531 SETGMEX
051019,000248: 13,2527 77735 SLOAD
051020,000249: 13,2530 11451 1B1 # MOON GAMMA
051021,000250: 13,2531 00011 SETGMEX STORE GAMRP
051022,000251: 13,2532 77616 RVQ
051023,000252: 13,2533 GAMRP = 8D
051024,000253:
051025,000254: # # Page 1209
051026,000255: # .....SETRE SUBROUTINE .....1
051027,000256: # SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
051028,000257:
051029,000258: # RE= RM FOR MOON
051030,000259: # RE= RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
051031,000260:
051032,000261: # CALLING SEQUENCE
051033,000262: # L CALL
051034,000263: # L+1 SETRE
051035,000264:
051036,000265: # SUBROUTINES USED
051037,000266: # CETERAD
051038,000267:
051039,000268: # INPUT
051040,000269: # ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED RE
051041,000270: # ALPHAV +4= 1/2 SINL IF GETERAD IS CALLED
051042,000271: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
051043,000272:
051044,000273: # OUTPUT
051045,000274: # ERADM= 504RM FOR MOON (METERS B-29)
051046,000275: # ERADM= ERAD OR COMPUTED RE FOR EARTH (METERS B-29)
051047,000276:
051048,000277: 13,2533 71220 SETRE STQ DLOAD
051049,000278: 13,2534 00051 SETREX
051050,000279: 13,2535 26560 504RM
051051,000280: 13,2536 71214 BON DLOAD # BRANCH FOR MOON
051052,000281: 13,2537 01703 LUNAFLAG
051053,000282: 13,2540 26550 TSTRLSRM
051054,000283: 13,2541 26462 ERAD
051055,000284: 13,2542 45014 BOFF CALL # ERADFLAG=0 FOR FIXED RE,1 FOR COMPUTED
051056,000285: 13,2543 00742 ERADFLAG
051057,000286: 13,2544 26546 SETRXX
051058,000287: 13,2545 26437 GETERAD
051059,000288: 13,2546 36241 SETRXX STCALL ERADM # EXIT WITH RE OR RM METERS B-29
051060,000289: 13,2547 00051 SETREX
051061,000290: 13,2550 77214 TSTRLSRM BON VLOAD # ERADFLAG=0,SET R0=RLS
051062,000291: 13,2551 00702 ERADFLAG # =1 R0=RM
051063,000292: 13,2552 26546 SETRXX
051064,000293: 13,2553 02026 RLS
051065,000294: 13,2554 64446 ABVAL SR2R # SCALE FROM B-27 TO B-29
051066,000295: 13,2555 77650 GOTO
051067,000296: 13,2556 26546 SETRXX
051068,000297: 13,2557 0000051 SETREX = S2
051069,000298: 13,2557 00065 01265 504RM 2DEC 1738090 B-29 # METERS B-29 (MOON RADIUS)
End of include-file LATITUDE_LONGITUDE_SUBROUTINES.agc. Parent file is MAIN.agc