GAP: ASSEMBLE REVISION 237 OF AGC PROGRAM COLOSSUS BY NASA 2021111-031 1:17 AUG. 24, 1968Note that the date is the date of the printout, not the date of the program revision.
Source Code
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These source-code files were derived from scans of the
Colossus 237 (Apollo 8 Command Module) program listing from the private collection of original
AGC developer Fred Martin. Scanning was by Ron Burkey. Pre-existing Colossus 249
(Apollo 9 CM) source files were used as a template, and changes between Colossus 249
and Colossus 237 were manually transcribed by a team of volunteers. 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, 1968Note that the date is the date of the printout, not the date of the program revision. |
051050,000002: ## Copyright: Public domain.
051051,000003: ## Filename: LATITUDE_LONGITUDE_SUBROUTINES.agc
051052,000004: ## Purpose: Part of the source code for Colossus build 237.
051053,000005: ## This is for the Command Module's (CM) Apollo Guidance
051054,000006: ## Computer (AGC), for Apollo 8.
051055,000007: ## Assembler: yaYUL
051056,000008: ## Contact: Jim Lawton <jim DOT lawton AT gmail DOT com>
051057,000009: ## Website: www.ibiblio.org/apollo/index.html
051058,000010: ## Page Scans: www.ibiblio.org/apollo/ScansForConversion/Colossus237/
051059,000011: ## Mod history: 2011-04-13 JL Adapted from corresponding Colossus 249 file.
051060,000012: ## 2017-01-01 RSB Proofed comment text using octopus/ProoferComments,
051061,000013: ## and fixed errors found.
051062,000014: ## 2017-02-05 RSB Back-ported comment corrections
051063,000015: ## identified while proofing Artemis 072.
051064,000016: ## 2017-03-15 RSB Comment-text fixes identified in 5-way
051065,000017: ## side-by-side diff of Luminary 69/99/116/131/210.
051066,000018:
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Page 1203 |
051068,000020: # SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
051069,000021:
051070,000022: # CALLING SEQUENCE
051071,000023:
051072,000024: # L-1 CALL
051073,000025: # L LAT-LONG
051074,000026: # SUBROUTINES USED
051075,000027:
051076,000028: # R-TO-RP,ARCTAN,SETGAMMA,SETRE
051077,000029: # ERASABLE INIT. REQ.
051078,000030:
051079,000031: # AXO,-AYO,AZO,TEPHEM (SET AT LAUNCH TIME)
051080,000032: # ALPHAV = POSITION VECTOR METERS B-29
051081,000033: # MPAC-- TIME (CSECS B-28)
051082,000034: # ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
051083,000035: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
051084,000036: # OUTPUT
051085,000037:
051086,000038: # LATITUDE IN LAT (REVS. B-0)
051087,000039: # LONGITUDE IN LONG (REVS. B-0)
051088,000040: # ALTITUDE IN ALT METERS B-29
051089,000041: 30,3776 BANK 30
051090,000042: 13,2000 SETLOC LATLONG
051091,000043: 13,2000 BANK
051092,000044:
051093,000045: 13,2322 COUNT 13/LT-LG
051094,000046:
051095,000047: 13,2322 E4,1551 EBANK= ALPHAV
051096,000048: 13,2322 40220 LAT-LONG STQ SETPD
051097,000049: 13,2323 02242 INCORPEX
051098,000050: 13,2324 00001 0D
051099,000051: 13,2325 24007 STOVL 6D # SAVE TIME IN 6-7D FOR R-TO-RP
051100,000052: 13,2326 02152 ALPHAV
051101,000053: 13,2327 51406 PUSH ABVAL # 0-5D= R FOR R-TO-RP
051102,000054: 13,2330 16310 STODL ALPHAM # ABS. VALUE OF R FOR ALT FORMULA BELOW
051103,000055: 13,2331 11453 ZEROVEC # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
051104,000056: 13,2332 71414 BOFF COS # USE COS(0) TO GET NON-ZERO IN MPAC
051105,000057: 13,2333 01743 LUNAFLAG # 0=EARTH,1=MOON
051106,000058: 13,2334 26335 CALLRTRP
051107,000059: 13,2335 77624 CALLRTRP CALL
051108,000060: 13,2336 55366 R-TO-RP # RP VECTOR CONVERTED FROM R B-29
051109,000061: 13,2337 77656 UNIT # UNIT RP B-1
051110,000062: 13,2340 36152 STCALL ALPHAV # U2= 1/2 SINL FOR SETRE SUBR BELOW
051111,000063: 13,2341 26523 SETGAMMA # SET GAMMA=B2/A2 FOR EARTH,=1 FOR MOON
051112,000064: 13,2342 77624 CALL # SCALED B-1
051113,000065: 13,2343 26533 SETRE # CALC RE METERS B-29
051114,000066: 13,2344 63545 DLOAD DSQ
051115,000067: 13,2345 02152 ALPHAV
051116,000068: 13,2346 63525 PDDL DSQ
051117,000069: 13,2347 02154 ALPHAV +2
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Page 1204 |
051119,000071: 13,2350 75415 DAD SQRT
051120,000072: 13,2351 76405 DMP SL1R
051121,000073: 13,2352 00011 GAMRP
051122,000074: 13,2353 14021 STODL COSTH # COS(LAT) B-1
051123,000075: 13,2354 02156 ALPHAV +4
051124,000076: 13,2355 34023 STCALL SINTH # SIN(LAT) B-1
051125,000077: 13,2356 26463 ARCTAN
051126,000078: 13,2357 15104 STODL LAT # LAT B0
051127,000079: 13,2360 02152 ALPHAV
051128,000080: 13,2361 14021 STODL COSTH # COS(LONG) B-1
051129,000081: 13,2362 02154 ALPHAV +2
051130,000082: 13,2363 34023 STCALL SINTH # SIN(LONG) B-1
051131,000083: 13,2364 26463 ARCTAN
051132,000084: 13,2365 15106 STODL LONG # LONG. REVS B-0 IN RANGE -1/2 TO 1/2
051133,000085: 13,2366 02310 ALPHAM
051134,000086: 13,2367 77625 DSU # ALT= R-RE METERS B-29
051135,000087: 13,2370 02241 ERADM
051136,000088: 13,2371 35110 STCALL ALT # EXIT WITH ALT METERS B-29
051137,000089: 13,2372 02242 INCORPEX
051138,000090:
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Page 1205 |
051140,000092: # SUBROUTINE TO CONVERT LAT,LONG,ALT AT GIVEN TIME TO RADIUS VECTOR
051141,000093: # CALLING SEQUENCE
051142,000094:
051143,000095: # L-1 CALL
051144,000096: # L LALOTORV
051145,000097: # SUBROUTINES USED
051146,000098:
051147,000099: # SETGAMMA,SETRE,RP-TO-R
051148,000100: # ERASABLE INIT. REQ.
051149,000101:
051150,000102: # AXO,AYO,AZO,TEPHEM SET AT LAUNCH TIME
051151,000103: # LAT-- LATITUDE (REVS B0)
051152,000104: # LONG-- LONGITUDE (REVS B0)
051153,000105: # ALT--ALTITUDE (METERS) B-29
051154,000106: # MPAC-- TIME (CSECS B-28)
051155,000107: # ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
051156,000108: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
051157,000109: # OUTPUT
051158,000110:
051159,000111: # R-VECTOR IN ALPHAV (METERS B-29)
051160,000112: 13,2373 40220 LALOTORV STQ SETPD # LAT,LONG,ALT TO R VECTOR
051161,000113: 13,2374 02242 INCORPEX
051162,000114: 13,2375 00001 0D
051163,000115: 13,2376 34007 STCALL 6D # 6-7D= TIME FOR RP-TO-R
051164,000116: 13,2377 26523 SETGAMMA # GAMMA=B2/A2 FOR EARTH,1 FOR MOON B-1
051165,000117: 13,2400 73545 DLOAD SIN # COS(LONG)COS(LAT) IN MPAC
051166,000118: 13,2401 01104 LAT # UNIT RP= SIN(LONG)COS(LAT) 2-3D
051167,000119: 13,2402 65275 DMPR PDDL # PD 2 GAMMA*SIN(LAT) 0-1D
051168,000120: 13,2403 00011 GAMRP
051169,000121: 13,2404 01104 LAT # 0-1D= GAMMA*SIN(LAT) B-2
051170,000122: 13,2405 65346 COS PDDL # PD 4 2-3D=COS(LAT) B-1 TEMPORARILY
051171,000123: 13,2406 01106 LONG
051172,000124: 13,2407 57356 SIN DMPR # PD 2
051173,000125: 13,2410 71525 PDDL COS # PD 4 2-3D=SIN(LONG)COS(LAT) B-2
051174,000126: 13,2411 01104 LAT
051175,000127: 13,2412 71525 PDDL COS # PD 6 4-5D=COS(LAT) B-1 TEMPORARILY
051176,000128: 13,2413 01106 LONG
051177,000129: 13,2414 55475 DMPR VDEF # PD4 MPAC= COS(LONG)COS(LAT) B-2
051178,000130: 13,2415 41456 UNIT PUSH # 0-5D= UNIT RP FOR RP-TO-R SUBR.
051179,000131: 13,2416 36152 STCALL ALPHAV # ALPHAV +4= SINL FOR SETRE SUBR.
051180,000132: 13,2417 26533 SETRE # RE METERS B-29
051181,000133: 13,2420 43145 DLOAD BOFF # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
051182,000134: 13,2421 11453 ZEROVEC
051183,000135: 13,2422 01743 LUNAFLAG
051184,000136: 13,2423 26425 CALLRPRT
051185,000137: 13,2424 77746 COS # USE COS(0) TO GET NON-ZERO IN MPAC
051186,000138: 13,2425 77624 CALLRPRT CALL
051187,000139: 13,2426 55341 RP-TO-R # EXIT WITH UNIT R VECTOR IN MPAC
051188,000140: 13,2427 16152 STODL ALPHAV
051189,000141: 13,2430 02241 ERADM
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Page 1206 |
051191,000143: 13,2431 74215 DAD VXSC # (RE + ALT)(UNIT R) METERS B-30
051192,000144: 13,2432 01110 ALT
051193,000145: 13,2433 02152 ALPHAV
051194,000146: 13,2434 77772 VSL1 # R METERS B-29
051195,000147: 13,2435 36152 STCALL ALPHAV # EXIT WITH R IN METERS B-29
051196,000148: 13,2436 02242 INCORPEX
051197,000149: # SUBROUTINE TO COMPUTE EARTH RADIUS
051198,000150:
051199,000151: # INPUT
051200,000152:
051201,000153: # 1/2 SIN LAT IN ALPHAV +4
051202,000154:
051203,000155: # OUTPUT
051204,000156:
051205,000157: # EARTH RADIUS IN ERADM AND MPAC (METERS B-29)
051206,000158:
051207,000159: 13,2437 63545 GETERAD DLOAD DSQ
051208,000160: 13,2440 02156 ALPHAV +4 # SIN**2(L)
051209,000161: 13,2441 44352 SL1 BDSU
051210,000162: 13,2442 11451 DP1/2 # COS**2(L)
051211,000163: 13,2443 44275 DMPR BDSU
051212,000164: 13,2444 26460 EE
051213,000165: 13,2445 11451 DP1/2
051214,000166: 13,2446 75465 BDDV SQRT
051215,000167: 13,2447 26454 B2XSC
051216,000168: 13,2450 77622 SR4R
051217,000169: 13,2451 02241 STORE ERADM
051218,000170: 13,2452 77616 RVQ
051219,000171:
051220,000172: # THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166,B=6356784 METERS
051221,000173: # B2XSC= B**2 SCALED B-51
051222,000174: # B2/A2= B**2/A**2 SCALED B-1
051223,000175: # EE=(1-B**2/A**2) SCALED B-0
051224,000176:
051225,000177: 13,2453 00446 00305 B2XSC 2DEC .0179450689 # B**2 SCALED B-51
051226,000178: 13,2455 04,3450 DP1/2 = XUNIT
051227,000179: 13,2455 17711 05254 B2/A2 2DEC .9933064884 B-1 # GAMMA= B**2/A**2 B-1
051228,000180: 13,2457 00155 25250 EE 2DEC 6.6935116 E-3 # (1-B**2/A**2) B-0
051229,000181: 13,2461 00302 17755 ERAD 2DEC 6373338 B-29 # PAD RADIUS
051230,000182:
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Page 1207 |
051232,000184: # ARCTAN SUBROUTINE
051233,000185:
051234,000186:
051235,000187: # CALLING SEQUENCE
051236,000188:
051237,000189: # SIN THETA IN SINTH B-1
051238,000190: # COS THETA IN COSTH B-1
051239,000191: # CALL ARCTAN
051240,000192:
051241,000193: # OUTPUT
051242,000194: # ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
051243,000195:
051244,000196:
051245,000197: 13,2463 77600 ARCTAN BOV
051246,000198: 13,2464 26465 CLROVFLW
051247,000199: 13,2465 63545 CLROVFLW DLOAD DSQ
051248,000200: 13,2466 00023 SINTH
051249,000201: 13,2467 63525 PDDL DSQ
051250,000202: 13,2470 00021 COSTH
051251,000203: 13,2471 77615 DAD
051252,000204: 13,2472 75454 BZE SQRT
051253,000205: 13,2473 26511 ARCTANXX # ATAN=0/0 SET THETA=0
051254,000206: 13,2474 40065 BDDV BOV
051255,000207: 13,2475 00023 SINTH
051256,000208: 13,2476 26516 ATAN=90
051257,000209: 13,2477 67542 SR1 ASIN
051258,000210: 13,2500 00025 STORE THETA
051259,000211: 13,2501 50125 PDDL BMN
051260,000212: 13,2502 00021 COSTH
051261,000213: 13,2503 26505 NEGCOS
051262,000214: 13,2504 43545 DLOAD RVQ
051263,000215: 13,2505 57545 NEGCOS DLOAD DCOMP
051264,000216: 13,2506 43244 BPL DAD
051265,000217: 13,2507 26513 NEGOUT
051266,000218: 13,2510 11451 DP1/2
051267,000219: 13,2511 00025 ARCTANXX STORE THETA
051268,000220: 13,2512 77616 RVQ
051269,000221:
051270,000222: 13,2513 52025 NEGOUT DSU GOTO
051271,000223: 13,2514 11451 DP1/2
051272,000224: 13,2515 26511 ARCTANXX
051273,000225: 13,2516 75345 ATAN=90 DLOAD SIGN
051274,000226: 13,2517 11477 LODP1/4
051275,000227: 13,2520 00023 SINTH
051276,000228: 13,2521 00025 STORE THETA
051277,000229: 13,2522 77616 RVQ
051278,000230:
051279,000231: 13,2523 04,3452 2DZERO = DPZERO
051280,000232:
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Page 1208 |
051282,000234: # ..... SETGAMMA SUBROUTINE .....
051283,000235: # SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
051284,000236:
051285,000237: # GAMMA = B**2/A**2 FOR EARTH (B-1)
051286,000238: # GAMMA = 1 FOR MOON (B-1)
051287,000239:
051288,000240: # CALLING SEQUENCE
051289,000241: # L CALL
051290,000242: # L+1 SETGAMMA
051291,000243:
051292,000244: # INPUT
051293,000245: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
051294,000246:
051295,000247: # OUTPUT
051296,000248: # GAMMA IN GAMRP (B-1)
051297,000249:
051298,000250: 13,2523 43145 SETGAMMA DLOAD BOFF # BRANCH FOR EARTH
051299,000251: 13,2524 26456 B2/A2 # EARTH GAMMA
051300,000252: 13,2525 01743 LUNAFLAG
051301,000253: 13,2526 26531 SETGMEX
051302,000254: 13,2527 77735 SLOAD
051303,000255: 13,2530 11451 1B1 # MOON GAMMA
051304,000256: 13,2531 00011 SETGMEX STORE GAMRP
051305,000257: 13,2532 77616 RVQ
051306,000258: 13,2533 GAMRP = 8D
051307,000259:
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Page 1209 |
051309,000261: # .....SETRE SUBROUTINE .....
051310,000262: # SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
051311,000263:
051312,000264: # RE= RM FOR MOON
051313,000265: # RE= RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
051314,000266:
051315,000267: # CALLING SEQUENCE
051316,000268: # L CALL
051317,000269: # L+1 SETRE
051318,000270:
051319,000271: # SUBROUTINES USED
051320,000272: # GETERAD
051321,000273:
051322,000274: # INPUT
051323,000275: # ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED RE
051324,000276: # ALPHAV +4= 1/2 SINL IF GETERAD IS CALLED
051325,000277: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
051326,000278:
051327,000279: # OUTPUT
051328,000280: # ERADM= 504RM FOR MOON (METERS B-29)
051329,000281: # ERADM= ERAD OR COMPUTED RF FOR EARTH (METERS B-29)
051330,000282:
051331,000283: 13,2533 71220 SETRE STQ DLOAD
051332,000284: 13,2534 00051 SETREX
051333,000285: 13,2535 26560 504RM
051334,000286: 13,2536 71214 BON DLOAD # BRANCH FOR MOON
051335,000287: 13,2537 01703 LUNAFLAG
051336,000288: 13,2540 26550 TSTRLSRM
051337,000289: 13,2541 26462 ERAD
051338,000290: 13,2542 45014 BOFF CALL # ERADFLAG=0 FOR FIXED RE,1 FOR COMPUTED
051339,000291: 13,2543 00742 ERADFLAG
051340,000292: 13,2544 26546 SETRXX
051341,000293: 13,2545 26437 GETERAD
051342,000294: 13,2546 36241 SETRXX STCALL ERADM # EXIT WITH RE OR RM METERS B-29
051343,000295: 13,2547 00051 SETREX
051344,000296: 13,2550 77214 TSTRLSRM BON VLOAD # ERADFLAG=0,SET R0=RLS
051345,000297: 13,2551 00702 ERADFLAG # =1 R0=RM
051346,000298: 13,2552 26546 SETRXX
051347,000299: 13,2553 02026 RLS
051348,000300: 13,2554 64446 ABVAL SR2R # SCALE FROM B-27 TO B-29
051349,000301: 13,2555 77650 GOTO
051350,000302: 13,2556 26546 SETRXX
051351,000303: 13,2557 0000051 SETREX = S2
051352,000304: 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