Source Code

051635,000001: # Copyright: Public domain. 051636,000002: # Filename: INFLIGHT_ALIGNMENT_ROUTINES.agc 051637,000003: # Purpose: A section of Luminary 1C, revision 131. 051638,000004: # It is part of the source code for the Lunar Module's (LM) 051639,000005: # Apollo Guidance Computer (AGC) for Apollo 13 and Apollo 14. 051640,000006: # This file is intended to be a faithful transcription, except 051641,000007: # that the code format has been changed to conform to the 051642,000008: # requirements of the yaYUL assembler rather than the 051643,000009: # original YUL assembler. 051644,000010: # Reference: pp. 1246-1255 of 1729.pdf. 051645,000011: # Contact: Ron Burkey <info@sandroid.org>. 051646,000012: # Website: www.ibiblio.org/apollo/index.html 051647,000013: # Mod history: 06/03/03 RSB. Began transcribing. 051648,000014: # 05/14/05 RSB. Corrected website reference above. 051649,000015: 051650,000016: # Page 1246 051651,000017: 22,3773 BANK 22 051652,000018: 23,2000 SETLOC INFLIGHT 051653,000019: 23,2000 BANK 051654,000020: 051655,000021: 23,3251 E5,1642 EBANK= XSM 051656,000022: 051657,000023: # CALCGTA COMPUTES THE GYRO TORQUE ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION. 051658,000024: 051659,000025: # THE INPUT IS THE DESIRED STABLE MEMBER COORDINATES REFERRED TO PRESENT STABLE MEMBER COORDINATES. THE THREE 051660,000026: # HALF-UNIT VECTORS ARE STORED AT XDC, YDC, AND ZDC. 051661,000027: 051662,000028: # THE OUTPUTS ARE THE THREE GYRO TORQUE ANGLES TO BE APPLIED TO THE Y, Z, AND X GYROS AND ARE STORED DP AT IGC, 051663,000029: # MGC, AND OGC RESPECTIVELY. 051664,000030: 051665,000031: 23,3251 COUNT* $$/INFLT 051666,000032: 23,3251 71220 CALCGTA ITA DLOAD # PUSHDOWN 00-03, 16D-27D, 34D-37D 051667,000033: 23,3252 00051 S2 # XDC = (XD1 XD2 XD3) 051668,000034: 23,3253 02665 XDC # YDC = (YD1 YD2 YD3) 051669,000035: 23,3254 65325 PDDL PDDL # ZDC = (ZD1 ZD2 ZD3) 051670,000036: 23,3255 06524 HI6ZEROS 051671,000037: 23,3256 02671 XDC +4 051672,000038: 23,3257 55476 DCOMP VDEF 051673,000039: 23,3260 77656 UNIT 051674,000040: 23,3261 14027 STODL ZPRIME # ZP = UNIT(-XD3 0 XD1) = (ZP1 ZP2 ZP3) 051675,000041: 23,3262 00027 ZPRIME 051676,000042: 051677,000043: 23,3263 77742 SR1 051678,000044: 23,3264 14023 STODL SINTH # SIN(IGC) = ZP1 051679,000045: 23,3265 00033 ZPRIME +4 051680,000046: 23,3266 77742 SR1 051681,000047: 23,3267 34021 STCALL COSTH # COS(IGC) = ZP3 051682,000048: 23,3270 47322 ARCTRIG 051683,000049: 051684,000050: 23,3271 16742 STODL IGC # Y GYRO TORQUING ANGLE FRACTION OF REV. 051685,000051: 23,3272 02667 XDC +2 051686,000052: 23,3273 77742 SR1 051687,000053: 23,3274 14023 STODL SINTH # SIN(MGC) = XD2 051688,000054: 23,3275 00027 ZPRIME 051689,000055: 051690,000056: 23,3276 65205 DMP PDDL 051691,000057: 23,3277 02671 XDC +4 # PD00 = (ZP1)(XD3) 051692,000058: 23,3300 00033 ZPRIME +4 051693,000059: 051694,000060: 23,3301 45205 DMP DSU 051695,000061: 23,3302 02665 XDC # MPAC = (ZP3)(XD1) 051696,000062: 23,3303 77626 STADR 051697,000063: 23,3304 43756 STCALL COSTH # COS(MGC) = MPAC - PD00 051698,000064: 23,3305 47322 ARCTRIG 051699,000065: # Page 1247 051700,000066: 23,3306 26744 STOVL MGC # Z GYRO TORQUING ANGLE FRACTION OF REV. 051701,000067: 23,3307 00027 ZPRIME 051702,000068: 23,3310 77641 DOT 051703,000069: 23,3311 02701 ZDC 051704,000070: 23,3312 24021 STOVL COSTH # COS(OGC) = ZP . ZDC 051705,000071: 23,3313 00027 ZPRIME 051706,000072: 23,3314 77641 DOT 051707,000073: 23,3315 02673 YDC 051708,000074: 23,3316 34023 STCALL SINTH # SIN(OGC) = ZP . YDC 051709,000075: 23,3317 47322 ARCTRIG 051710,000076: 051711,000077: 23,3320 36740 STCALL OGC # X GYRO TORQUING ANGLE FRACTION OF REV. 051712,000078: 23,3321 00051 S2 051713,000079: 051714,000080: # Page 1248 051715,000081: # ARCTRIG COMPUTES AN ANGLE GIVEN THE SINE AND COSINE OF THIS ANGLE. 051716,000082: 051717,000083: # THE INPUTS ARE SIN/4 AND COS/4 STORED UP AT SINTH AND COSTH. 051718,000084: 051719,000085: # THE OUTPUT IS THE CALCULATED ANGLE BETWEEN +.5 AND -.5 REVOLUTIONS AND STORED AT THETA. THE OUTPUT IS ALSO 051720,000086: # AVAILABLE AT MPAC. 051721,000087: 051722,000088: 23,3322 51545 ARCTRIG DLOAD ABS # PUSHDOWN 16D-21D 051723,000089: 23,3323 00023 SINTH 051724,000090: 23,3324 50025 DSU BMN 051725,000091: 23,3325 07536 QTSN45 # ABS(SIN/4) - SIN(45)/4 051726,000092: 23,3326 47335 TRIG1 # IF (-45,45) OR (135,-135) 051727,000093: 051728,000094: 23,3327 72545 DLOAD SL1 # (45,135) OR (-135,-45) 051729,000095: 23,3330 00021 COSTH 051730,000096: 23,3331 75326 ACOS SIGN 051731,000097: 23,3332 00023 SINTH 051732,000098: 23,3333 00025 STORE THETA # X = ARCCOS(COS) WITH SIGN(SIN) 051733,000099: 23,3334 77616 RVQ 051734,000100: 051735,000101: 23,3335 72545 TRIG1 DLOAD SL1 # (-45,45) OR (135,-135) 051736,000102: 23,3336 00023 SINTH 051737,000103: 23,3337 77736 ASIN 051738,000104: 23,3340 14025 STODL THETA # X = ARCSIN(SIN) WITH SIGN(SIN) 051739,000105: 23,3341 00021 COSTH 051740,000106: 23,3342 77640 BMN 051741,000107: 23,3343 47346 TRIG2 # IF (135,-135) 051742,000108: 051743,000109: 23,3344 43545 DLOAD RVQ 051744,000110: 23,3345 00025 THETA # X = ARCSIN(SIN) (-45,45) 051745,000111: 051746,000112: 23,3346 75345 TRIG2 DLOAD SIGN # (135,-135) 051747,000113: 23,3347 06522 HIDPHALF 051748,000114: 23,3350 00023 SINTH 051749,000115: 23,3351 77625 DSU 051750,000116: 23,3352 00025 THETA 051751,000117: 23,3353 00025 STORE THETA # X = .5 WITH SIGN(SIN) - ARCSIN(SIN) 051752,000118: 23,3354 77616 RVQ # (+) - (+) OR (-) - (-) 051753,000119: 051754,000120: # Page 1249 051755,000121: # SMNB, NBSM, AND AXISROT, WHICH USED TO APPEAR HERE, HAVE BEEN 051756,000122: # COMBINED IN A ROUTINE CALLED AX*SR*T, WHICH APPEARS AMONG THE POWERED 051757,000123: # FLIGHT SUBROUTINES. 051758,000124: 051759,000125: # Page 1250 051760,000126: # CALCGA COMPUTES THE CDU DRIVING ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION. 051761,000127: 051762,000128: # THE INPUTS ARE 1) THE NAVIGATION BASE COORDINATES REFERRED TO ANY COORDINATE SYSTEM. THE THREE HALF-UNIT 051763,000129: # VECTORS ARE STORED AT XNB, YNB, AND ZNB. 2) THE DESIRED STABLE MEMBER COORDINATES REFERRED TO THE SAME 051764,000130: # COORDINATE SYSTEM ARE STORED AT XSM, YSM, AND ZSM. 051765,000131: 051766,000132: # THE OUTPUTS ARE THE THREE CDU DRIVING ANGLES AND ARE STORED SP AT THETAD, THETAD +1, AND THETAD +2. 051767,000133: 051768,000134: 23,3355 77601 CALCGA SETPD # PUSHDOWN 00-05, 16D-21D, 34D-37D 051769,000135: 23,3356 00001 0 051770,000136: 23,3357 47375 VLOAD VXV 051771,000137: 23,3360 02665 XNB # XNB = OGA (OUTER GIMBAL AXIS) 051772,000138: 23,3361 02651 YSM # YSM = IGA (INNER GIMBAL AXIS) 051773,000139: 23,3362 41456 UNIT PUSH # PD0 = UNIT(OGA X IGA) = MGA 051774,000140: 051775,000141: 23,3363 44041 DOT ITA 051776,000142: 23,3364 02701 ZNB 051777,000143: 23,3365 00051 S2 051778,000144: 23,3366 24021 STOVL COSTH # COS(OG) = MGA . ZNB 051779,000145: 23,3367 00001 0 051780,000146: 23,3370 77641 DOT 051781,000147: 23,3371 02673 YNB 051782,000148: 23,3372 34023 STCALL SINTH # SIN(OG) = MGA . YNB 051783,000149: 23,3373 47322 ARCTRIG 051784,000150: 23,3374 26740 STOVL OGC 051785,000151: 23,3375 00001 0 051786,000152: 051787,000153: 23,3376 50235 VXV DOT # PROVISION FOR MG ANGLE OF 90 DEGREES 051788,000154: 23,3377 02665 XNB 051789,000155: 23,3400 02651 YSM 051790,000156: 23,3401 77752 SL1 051791,000157: 23,3402 24021 STOVL COSTH # COS(MG) = IGA . (MGA X OGA) 051792,000158: 23,3403 02651 YSM 051793,000159: 23,3404 77641 DOT 051794,000160: 23,3405 02665 XNB 051795,000161: 23,3406 34023 STCALL SINTH # SIN(MG) = IGA . OGA 051796,000162: 23,3407 47322 ARCTRIG 051797,000163: 23,3410 02744 STORE MGC 051798,000164: 051799,000165: 23,3411 45246 ABS DSU 051800,000166: 23,3412 07540 .166... 051801,000167: 23,3413 77644 BPL 051802,000168: 23,3414 47433 GIMLOCK1 # IF ANGLE GREATER THAN 60 DEGREES 051803,000169: 051804,000170: 23,3415 50375 CALCGA1 VLOAD DOT 051805,000171: 23,3416 02657 ZSM 051806,000172: 23,3417 00001 0 051807,000173: 23,3420 24021 STOVL COSTH # COS(IG) = ZSM . MGA 051808,000174: 23,3421 02643 XSM 051809,000175: # Page 1251 051810,000176: 23,3422 45441 DOT STADR 051811,000177: 23,3423 43754 STCALL SINTH # SIN(IG) = XSM . MGA 051812,000178: 23,3424 47322 ARCTRIG 051813,000179: 051814,000180: 23,3425 26742 STOVL IGC 051815,000181: 23,3426 02740 OGC 051816,000182: 23,3427 77634 RTB 051817,000183: 23,3430 21621 V1STO2S 051818,000184: 23,3431 34322 STCALL THETAD 051819,000185: 23,3432 00051 S2 051820,000186: 051821,000187: 23,3433 77776 GIMLOCK1 EXIT 051822,000188: 23,3434 05567 TC ALARM 051823,000189: 23,3435 00401 OCT 00401 051824,000190: 23,3436 05504 TC UPFLAG # GIMBAL LOCK HAS OCCURRED 051825,000191: 23,3437 00056 ADRES GLOKFAIL 051826,000192: 051827,000193: 23,3440 06042 TC INTPRET 051828,000194: 23,3441 77650 GOTO 051829,000195: 23,3442 47415 CALCGA1 051830,000196: 051831,000197: # Page 1252 051832,000198: # AXISGEN COMPUTES THE COORDINATES OF ONE COORDINATE SYSTEM REFERRED TO ANOTHER COORDINATE SYSTEM. 051833,000199: 051834,000200: # THE INPUTS ARE 1) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM A STORED AT STARAD. 2) THE STAR2 VECTOR 051835,000201: # REFERRED TO COORDINATE SYSTEM A STORED AT STARAD +6. 3) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM B STORED 051836,000202: # AT LOCATION 6 OF THE VAC AREA. 4) THE STAR2 VECTOR REFERRED TO COORDINATE SYSTEM B STORED AT LOCATION 12D OF 051837,000203: # THE VAC AREA. 051838,000204: 051839,000205: # THE OUTPUT DEFINES COORDINATE SYSTEM A REFERRED TO COORDINATE SYSTEM B. THE THREE HALF-UNIT VECTORS ARE STORED 051840,000206: # AT LOCATIONS XDC, XDC +6, XDC +12D, AND STARAD, STARAD +6, STARAD +12D. 051841,000207: 051842,000208: 23,3443 66370 AXISGEN AXT,1 SSP # PUSHDOWN 00-30D, 34D-37D 051843,000209: 23,3444 02714 STARAD +6 051844,000210: 23,3445 00051 S1 051845,000211: 23,3446 02700 STARAD -6 051846,000212: 051847,000213: 23,3447 77601 SETPD 051848,000214: 23,3450 00001 0 051849,000215: 23,3451 46773 AXISGEN1 VLOAD* VXV* # 06D UA = S1 051850,000216: 23,3452 02723 STARAD +12D,1 # STARAD +00D UB = S1 051851,000217: 23,3453 02731 STARAD +18D,1 051852,000218: 23,3454 77656 UNIT # 12D VA = UNIT(S1 X S2) 051853,000219: 23,3455 06731 STORE STARAD +18D,1 # STARAD +06D VB = UNIT(S1 X S2) 051854,000220: 23,3456 77773 VLOAD* 051855,000221: 23,3457 02723 STARAD +12D,1 051856,000222: 051857,000223: 23,3460 76433 VXV* VSL1 051858,000224: 23,3461 02731 STARAD +18D,1 # 18D WA = UA X VA 051859,000225: 23,3462 06737 STORE STARAD +24D,1 # STARAD +12D WB = UB X VB 051860,000226: 051861,000227: 23,3463 77700 TIX,1 051862,000228: 23,3464 47451 AXISGEN1 051863,000229: 051864,000230: 23,3465 66160 AXC,1 SXA,1 051865,000231: 23,3466 00006 6 051866,000232: 23,3467 00036 30D 051867,000233: 051868,000234: 23,3470 66370 AXT,1 SSP 051869,000235: 23,3471 00022 18D 051870,000236: 23,3472 00051 S1 051871,000237: 23,3473 00006 6 051872,000238: 051873,000239: 23,3474 66374 AXT,2 SSP 051874,000240: 23,3475 00006 6 051875,000241: 23,3476 00052 S2 051876,000242: 23,3477 00002 2 051877,000243: 051878,000244: 23,3500 76720 AXISGEN2 XCHX,1 VLOAD* 051879,000245: 23,3501 00036 30D # X1=-6 X2=+6 X1=-6 X2=+4 X1=-6 X2=+2 051880,000246: 23,3502 00001 0,1 051881,000247: 051882,000248: # Page 1253 051883,000249: 23,3503 62757 VXSC* PDVL* # J=(UA)(UB1) J=(UA)(UB2) J=(UA)(UB3) 051884,000250: 23,3504 75062 STARAD +6,2 051885,000251: 23,3505 00007 6,1 051886,000252: 23,3506 77757 VXSC* 051887,000253: 23,3507 75054 STARAD +12D,2 051888,000254: 23,3510 30031 STOVL* 24D # K=(VA)(VB1) J=(VA)(VB2) J=(VA)(VB3) 051889,000255: 23,3511 00015 12D,1 051890,000256: 051891,000257: 23,3512 53357 VXSC* VAD 051892,000258: 23,3513 75046 STARAD +18D,2 # L=(WA)(WB1) J=(WA)(WB2) J=(WA)(WB3) 051893,000259: 23,3514 76455 VAD VSL1 051894,000260: 23,3515 00031 24D 051895,000261: 23,3516 53520 XCHX,1 UNIT 051896,000262: 23,3517 00036 30D 051897,000263: 23,3520 06707 STORE XDC +18D,1 # XDC = L+J+K YDC = L+J+K ZDC = L+J+K 051898,000264: 051899,000265: 23,3521 77700 TIX,1 051900,000266: 23,3522 47523 AXISGEN3 051901,000267: 051902,000268: 23,3523 77704 AXISGEN3 TIX,2 051903,000269: 23,3524 47500 AXISGEN2 051904,000270: 051905,000271: 23,3525 77775 VLOAD 051906,000272: 23,3526 02665 XDC 051907,000273: 23,3527 26707 STOVL STARAD 051908,000274: 23,3530 02673 YDC 051909,000275: 23,3531 26715 STOVL STARAD +6 051910,000276: 23,3532 02701 ZDC 051911,000277: 23,3533 02723 STORE STARAD +12D 051912,000278: 051913,000279: 23,3534 77616 RVQ 051914,000280: 051915,000281: # Page 1254 051916,000282: 23,3535 05520 26075 QTSN45 2DEC .1768 051917,000283: 23,3537 05252 25253 .166... 2DEC .1666666667 051918,000284: 051919,000285: # Page 1255 051920,000286: # (There is no source code on this page of the original assembly listing.) End of include-file INFLIGHT_ALIGNMENT_ROUTINES.agc. Parent file is MAIN.agc