Source Code
|
These source-code files are part of a reconstructed copy of Luminary 163, the
first (unflown) release of the Apollo 14 Lunar Module (LM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with reconstructed source code for Luminary 173. Changes
between revision 163 and 173 were backed out, as described by Luminary memos 157
and 158. 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 163 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.
|
047563,000002: ## Copyright: Public domain.
047564,000003: ## Filename: LATITUDE_LONGITUDE_SUBROUTINES.agc
047565,000004: ## Purpose: A section of Luminary revision 163.
047566,000005: ## It is part of the reconstructed source code for the first
047567,000006: ## (unflown) release of the flight software for the Lunar
047568,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 14.
047569,000008: ## The code has been recreated from a reconstructed copy of
047570,000009: ## Luminary 173, as well as Luminary memos 157 amd 158.
047571,000010: ## It has been adapted such that the resulting bugger words
047572,000011: ## exactly match those specified for Luminary 163 in NASA
047573,000012: ## drawing 2021152N, which gives relatively high confidence
047574,000013: ## that the reconstruction is correct.
047575,000014: ## Reference: pp. 1124-1130
047576,000015: ## Assembler: yaYUL
047577,000016: ## Contact: Ron Burkey <info@sandroid.org>.
047578,000017: ## Website: www.ibiblio.org/apollo/index.html
047579,000018: ## Mod history: 2019-08-21 MAS Created from Luminary 173.
047580,000019:
|
|
Page 1124
|
047582,000021: # SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
047583,000022:
047584,000023: # CALLING SEQUENCE
047585,000024:
047586,000025: # L-1 CALL
047587,000026: # L LAT-LONG
047588,000027: # SUBROUTINES USED
047589,000028:
047590,000029: # R-TO-RP,ARCTAN,SETGAMMA,SETRE
047591,000030: # ERASABLE INIT. REQ.
047592,000031:
047593,000032: # AXO,-AYO,AZO,TEPHEM (SET AT LAUNCH TIME)
047594,000033: # ALPHAV = POSITION VECTOR METERS B-29
047595,000034: # MPAC-- TIME (CSECS B-28)
047596,000035: # ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
047597,000036: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
047598,000037: # OUTPUT
047599,000038:
047600,000039: # LATITUDE IN LAT (REVS. B-0)
047601,000040: # LONGITUDE IN LONG (REVS. B-0)
047602,000041: # ALTITUDE IN ALT METERS B-29
047603,000042: 30,3760 BANK 30
047604,000043: 13,2000 SETLOC LATLONG
047605,000044: 13,2000 BANK
047606,000045:
047607,000046: 13,2347 COUNT* $$/LT-LG
047608,000047: 13,2347 E4,1431 EBANK= ALPHAV
047609,000048: 13,2347 40220 LAT-LONG STQ SETPD
047610,000049: 13,2350 03674 INCORPEX
047611,000050: 13,2351 00001 0D
047612,000051: 13,2352 24007 STOVL 6D # SAVE TIME IN 6-7D FOR R-TO-RP
047613,000052: 13,2353 02032 ALPHAV
047614,000053: 13,2354 51406 PUSH ABVAL # 0-5D= R FOR R-TO-RP
047615,000054: 13,2355 16070 STODL ALPHAM # ABS. VALUE OF R FOR ALT FORMULA BELOW
047616,000055: 13,2356 24007 ZEROVEC # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
047617,000056: 13,2357 71414 BOFF COS # USE COS(0) TO GET NON-ZERO IN MPAC
047618,000057: 13,2360 01743 LUNAFLAG # 0=EARTH,1=MOON
047619,000058: 13,2361 26362 CALLRTRP
047620,000059: 13,2362 77624 CALLRTRP CALL
047621,000060: 13,2363 51632 R-TO-RP # RP VECTOR CONVERTED FROM R B-29
047622,000061: 13,2364 77656 UNIT # UNIT RP B-1
047623,000062: 13,2365 36032 STCALL ALPHAV # U2= 1/2 SINL FOR SETRE SUBR BELOW
047624,000063: 13,2366 26546 SETGAMMA # SET GAMMA=B2/A2 FOR EARTH,=1 FOR MOON
047625,000064: 13,2367 77624 CALL # SCALED B-1
047626,000065: 13,2370 26556 SETRE # CALC RE METERS B-29
047627,000066: 13,2371 63545 DLOAD DSQ
047628,000067: 13,2372 02032 ALPHAV
047629,000068: 13,2373 63525 PDDL DSQ
047630,000069: 13,2374 02034 ALPHAV +2
047631,000070: 13,2375 75415 DAD SQRT
|
|
Page 1125
|
047633,000072: 13,2376 76405 DMP SL1R
047634,000073: 13,2377 00011 GAMRP
047635,000074: 13,2400 14021 STODL COSTH # COS(LAT) B-1
047636,000075: 13,2401 02036 ALPHAV +4
047637,000076: 13,2402 34023 STCALL SINTH # SIN(LAT) B-1
047638,000077: 13,2403 26506 ARCTAN
047639,000078: 13,2404 15120 STODL LAT # LAT B0
047640,000079: 13,2405 02032 ALPHAV
047641,000080: 13,2406 14021 STODL COSTH # COS(LONG) B-1
047642,000081: 13,2407 02034 ALPHAV +2
047643,000082: 13,2410 34023 STCALL SINTH # SIN(LONG) B-1
047644,000083: 13,2411 26506 ARCTAN
047645,000084: 13,2412 15122 STODL LONG # LONG. REVS B-0 IN RANGE -1/2 TO 1/2
047646,000085: 13,2413 02070 ALPHAM
047647,000086: 13,2414 77625 DSU # ALT= R-RE METERS B-29
047648,000087: 13,2415 03673 ERADM
047649,000088: 13,2416 35124 STCALL ALT # EXIT WITH ALT METERS B-29
047650,000089: 13,2417 03674 INCORPEX
047651,000090:
|
|
Page 1126
|
047653,000092: # SUBROUTINE TO CONVERT LAT,LONG,ALT AT GIVEN TIME TO RADIUS VECTOR
047654,000093: # CALLING SEQUENCE
047655,000094:
047656,000095: # L-1 CALL
047657,000096: # L LALOTORV
047658,000097: # SUBROUTINES USED
047659,000098:
047660,000099: # SETGAMMA,SETRE,RP-TO-R
047661,000100: # ERASABLE INIT. REQ.
047662,000101:
047663,000102: # AXO,AYO,AZO,TEPHEM SET AT LAUNCH TIME
047664,000103: # LAT-- LATITUDE (REVS B0)
047665,000104: # LONG-- LONGITUDE (REVS B0)
047666,000105: # ALT--ALTITUDE (METERS) B-29
047667,000106: # MPAC-- TIME (CSECS B-28)
047668,000107: # ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
047669,000108: # LUNAFLAG=0 FOR EARTH,1 FOR MOON
047670,000109: # OUTPUT
047671,000110:
047672,000111: # R-VECTOR IN ALPHAV (METERS B-29)
047673,000112: 13,2420 40220 LALOTORV STQ SETPD # LAT,LONG,ALT TO R VECTOR
047674,000113: 13,2421 03674 INCORPEX
047675,000114: 13,2422 00001 0D
047676,000115: 13,2423 34007 STCALL 6D # 6-7D= TIME FOR RP-TO-R
047677,000116: 13,2424 26546 SETGAMMA # GAMMA=B2/A2 FOR EARTH,1 FOR MOON B-1
047678,000117: 13,2425 73545 DLOAD SIN # COS(LONG)COS(LAT) IN MPAC
047679,000118: 13,2426 01120 LAT # UNIT RP= SIN(LONG)COS(LAT) 2-3D
047680,000119: 13,2427 65275 DMPR PDDL # PD 2 GAMMA*SIN(LAT) 0-1D
047681,000120: 13,2430 00011 GAMRP
047682,000121: 13,2431 01120 LAT # 0-1D= GAMMA*SIN(LAT) B-2
047683,000122: 13,2432 65346 COS PDDL # PD4 2-3D=COS(LAT) B-1 TEMPORARILY
047684,000123: 13,2433 01122 LONG
047685,000124: 13,2434 57356 SIN DMPR # PD 2
047686,000125: 13,2435 71525 PDDL COS # PD 4 2-3D=SIN(LONG)COS(LAT) B-2
047687,000126: 13,2436 01120 LAT
047688,000127: 13,2437 71525 PDDL COS # PD 6 4-5D=COS(LAT) B-1 TEMPORARILY
047689,000128: 13,2440 01122 LONG
047690,000129: 13,2441 55475 DMPR VDEF # PD 4 MPAC= COS(LONG)COS(LAT) B-2
047691,000130: 13,2442 41456 UNIT PUSH # 0-5D= UNIT RP FOR RP-TO-R SUBR.
047692,000131: 13,2443 36032 STCALL ALPHAV # ALPHAV +4= SINL FOR SETRE SUBR.
047693,000132: 13,2444 26556 SETRE # RE METERS B-29
047694,000133: 13,2445 43145 DLOAD BOFF # SET MPAC=0 FOR EARTH,NON-ZERO FOR MOON
047695,000134: 13,2446 24007 ZEROVEC
047696,000135: 13,2447 01743 LUNAFLAG
047697,000136: 13,2450 26452 CALLRPRT
047698,000137: 13,2451 77746 COS # USE COS(0) TO GET NON-ZERO IN MPAC
047699,000138: 13,2452 77624 CALLRPRT CALL
047700,000139: 13,2453 55720 RP-TO-R # EXIT WITH UNIT R VECTOR IN MPAC
047701,000140: 13,2454 16032 STODL ALPHAV
047702,000141: 13,2455 03673 ERADM
|
|
Page 1127
|
047704,000143: 13,2456 74215 DAD VXSC # (RE + ALT)(UNIT R) METERS B-30
047705,000144: 13,2457 01124 ALT
047706,000145: 13,2460 02032 ALPHAV
047707,000146: 13,2461 77772 VSL1 # R METERS B-29
047708,000147: 13,2462 36032 STCALL ALPHAV # EXIT WITH R IN METERS B-29
047709,000148: 13,2463 03674 INCORPEX
047710,000149: # SUBROUTINE TO COMPUTE EARTH RADIUS
047711,000150:
047712,000151: # INPUT
047713,000152:
047714,000153: # 1/2 SIN LAT IN ALPHAV +4
047715,000154:
047716,000155: # OUTPUT
047717,000156:
047718,000157: # EARTH RADIUS IN ERADM AND MPAC (METERS B-29)
047719,000158:
047720,000159: 13,2464 63545 GETERAD DLOAD DSQ
047721,000160: 13,2465 02036 ALPHAV +4 # SIN**2(L)
047722,000161: 13,2466 44352 SL1 BDSU
047723,000162: 13,2467 24005 DP1/2 # COS**2(L)
047724,000163: 13,2470 44275 DMPR BDSU
047725,000164: 13,2471 26505 EE
047726,000165: 13,2472 24005 DP1/2
047727,000166: 13,2473 75465 BDDV SQRT
047728,000167: 13,2474 26501 B2XSC
047729,000168: 13,2475 77622 SR4R
047730,000169: 13,2476 03673 STORE ERADM
047731,000170: 13,2477 77616 RVQ
047732,000171:
047733,000172: # THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166,B=6356784 METERS
047734,000173: # B2XSC= B**2 SCALED B-51
047735,000174: # B2/A2= B**2/A**2 SCALED B-1
047736,000175: # EE=(1-B**2/A**2) SCALED B-0
047737,000176: 13,2500 00446 00305 B2XSC 2DEC .0179450689 # B**2 SCALED B-51
047738,000177:
047739,000178: 13,2502 12,2004 DP1/2 = XUNIT
047740,000179: 13,2502 17711 05254 B2/A2 2DEC .9933064884 B-1 # GAMMA= B**2/A**2 B-1
047741,000180:
047742,000181: 13,2504 00155 25250 EE 2DEC 6.6935116 E-3 # (1-B**2/A**2) B-0
047743,000182:
|
|
Page 1128
|
047745,000184: # ARCTAN SUBROUTINE
047746,000185:
047747,000186:
047748,000187: # CALLING SEQUENCE
047749,000188:
047750,000189: # SIN THETA IN SINTH B-1
047751,000190: # COS THETA IN COSTH B-1
047752,000191: # CALL ARCTAN
047753,000192:
047754,000193: # OUTPUT
047755,000194: # ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
047756,000195:
047757,000196:
047758,000197: 13,2506 77600 ARCTAN BOV
047759,000198: 13,2507 26510 CLROVFLW
047760,000199: 13,2510 63545 CLROVFLW DLOAD DSQ
047761,000200: 13,2511 00023 SINTH
047762,000201: 13,2512 63525 PDDL DSQ
047763,000202: 13,2513 00021 COSTH
047764,000203: 13,2514 77615 DAD
047765,000204: 13,2515 75454 BZE SQRT
047766,000205: 13,2516 26534 ARCTANXX # ATAN=0/0 SET THETA=0
047767,000206: 13,2517 40065 BDDV BOV
047768,000207: 13,2520 00023 SINTH
047769,000208: 13,2521 26541 ATAN=90
047770,000209: 13,2522 67542 SR1 ASIN
047771,000210: 13,2523 00025 STORE THETA
047772,000211: 13,2524 50125 PDDL BMN
047773,000212: 13,2525 00021 COSTH
047774,000213: 13,2526 26530 NEGCOS
047775,000214: 13,2527 43545 DLOAD RVQ
047776,000215: 13,2530 57545 NEGCOS DLOAD DCOMP
047777,000216: 13,2531 43244 BPL DAD
047778,000217: 13,2532 26536 NEGOUT
047779,000218: 13,2533 24005 DP1/2
047780,000219: 13,2534 00025 ARCTANXX STORE THETA
047781,000220: 13,2535 77616 RVQ
047782,000221:
047783,000222: 13,2536 52025 NEGOUT DSU GOTO
047784,000223: 13,2537 24005 DP1/2
047785,000224: 13,2540 26534 ARCTANXX
047786,000225: 13,2541 75345 ATAN=90 DLOAD SIGN
047787,000226: 13,2542 11011 LODP1/4
047788,000227: 13,2543 00023 SINTH
047789,000228: 13,2544 00025 STORE THETA
047790,000229: 13,2545 77616 RVQ
047791,000230:
047792,000231: 13,2546 12,2006 2DZERO = DPZERO
047793,000232:
|
|
Page 1129
|
047795,000234: # ..... SETGAMMA SUBROUTINE .....
047796,000235: # SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
047797,000236:
047798,000237: # GAMMA = B**2/A**2 FOR EARTH (B-1)
047799,000238: # GAMMA = 1 FOR MOON (B-1)
047800,000239:
047801,000240: # CALLING SEQUENCE
047802,000241: # L CALL
047803,000242: # L+1 SETGAMMA
047804,000243:
047805,000244: # INPUT
047806,000245: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
047807,000246:
047808,000247: # OUTPUT
047809,000248: # GAMMA IN GAMRP (B-1)
047810,000249:
047811,000250: 13,2546 43145 SETGAMMA DLOAD BOFF # BRANCH FOR EARTH
047812,000251: 13,2547 26503 B2/A2 # EARTH GAMMA
047813,000252: 13,2550 01743 LUNAFLAG
047814,000253: 13,2551 26554 SETGMEX
047815,000254: 13,2552 77735 SLOAD
047816,000255: 13,2553 24005 1B1 # MOON GAMMA
047817,000256: 13,2554 00011 SETGMEX STORE GAMRP
047818,000257: 13,2555 77616 RVQ
047819,000258: 13,2556 GAMRP = 8D
047820,000259:
|
|
Page 1130
|
047822,000261: # .....SETRE SUBROUTINE .....
047823,000262: # SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
047824,000263:
047825,000264: # RE= RM FOR MOON
047826,000265: # RE= RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
047827,000266:
047828,000267: # CALLING SEQUENCE
047829,000268: # L CALL
047830,000269: # L+1 SETRE
047831,000270:
047832,000271: # SUBROUTINES USED
047833,000272: # GETERAD
047834,000273:
047835,000274: # INPUT
047836,000275: # ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED RE
047837,000276: # ALPHAV +4= 1/2 SINL IF GETERAD IS CALLED
047838,000277: # LUNAFLAG=0 FOR EARTH,=1 FOR MOON
047839,000278:
047840,000279: # OUTPUT
047841,000280: # ERADM= 504RM FOR MOON (METERS B-29)
047842,000281: # ERADM= ERAD OR COMPUTED RF FOR EARTH (METERS B-29)
047843,000282:
047844,000283: 13,2556 71220 SETRE STQ DLOAD
047845,000284: 13,2557 00051 SETREX
047846,000285: 13,2560 10003 504RM
047847,000286: 13,2561 71214 BON DLOAD # BRANCH FOR MOON
047848,000287: 13,2562 01703 LUNAFLAG
047849,000288: 13,2563 26573 TSTRLSRM
047850,000289: 13,2564 10001 ERAD
047851,000290: 13,2565 45014 BOFF CALL # ERADFLAG=0 FOR FIXED RE,1 FOR COMPUTED
047852,000291: 13,2566 00742 ERADFLAG
047853,000292: 13,2567 26571 SETRXX
047854,000293: 13,2570 26464 GETERAD
047855,000294: 13,2571 37673 SETRXX STCALL ERADM # EXIT WITH RE OR RM METERS B-29
047856,000295: 13,2572 00051 SETREX
047857,000296: 13,2573 77214 TSTRLSRM BON VLOAD # ERADFLAG=0,SET R0=RLS
047858,000297: 13,2574 00702 ERADFLAG # =1 R0=RM
047859,000298: 13,2575 26571 SETRXX
047860,000299: 13,2576 02021 RLS
047861,000300: 13,2577 64446 ABVAL SR2R # SCALE FROM B-27 TO B-29
047862,000301: 13,2600 77650 GOTO
047863,000302: 13,2601 26571 SETRXX
047864,000303: 13,2602 0000051 SETREX = S2
End of include-file LATITUDE_LONGITUDE_SUBROUTINES.agc. Parent file is MAIN.agc