Source Code
051604,000001: # Copyright: Public domain.
051605,000002: # Filename: INFLIGHT_ALIGNMENT_ROUTINES.agc
051606,000003: # Purpose: A section of Luminary 1C, revision 131.
051607,000004: # It is part of the source code for the Lunar Module's (LM)
051608,000005: # Apollo Guidance Computer (AGC) for Apollo 13 and Apollo 14.
051609,000006: # This file is intended to be a faithful transcription, except
051610,000007: # that the code format has been changed to conform to the
051611,000008: # requirements of the yaYUL assembler rather than the
051612,000009: # original YUL assembler.
051613,000010: # Reference: pp. 1246-1255 of 1729.pdf.
051614,000011: # Contact: Ron Burkey <info@sandroid.org>.
051615,000012: # Website: www.ibiblio.org/apollo/index.html
051616,000013: # Mod history: 06/03/03 RSB. Began transcribing.
051617,000014: # 05/14/05 RSB. Corrected website reference above.
051618,000015:
051619,000016: # Page 1246
051620,000017: 22,3773 BANK 22
051621,000018: 23,2000 SETLOC INFLIGHT
051622,000019: 23,2000 BANK
051623,000020:
051624,000021: 23,3251 E5,1642 EBANK= XSM
051625,000022:
051626,000023: # CALCGTA COMPUTES THE GYRO TORQUE ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION.
051627,000024:
051628,000025: # THE INPUT IS THE DESIRED STABLE MEMBER COORDINATES REFERRED TO PRESENT STABLE MEMBER COORDINATES. THE THREE
051629,000026: # HALF-UNIT VECTORS ARE STORED AT XDC, YDC, AND ZDC.
051630,000027:
051631,000028: # THE OUTPUTS ARE THE THREE GYRO TORQUE ANGLES TO BE APPLIED TO THE Y, Z, AND X GYROS AND ARE STORED DP AT IGC,
051632,000029: # MGC, AND OGC RESPECTIVELY.
051633,000030:
051634,000031: 23,3251 COUNT* $$/INFLT
051635,000032: 23,3251 71220 CALCGTA ITA DLOAD # PUSHDOWN 00-03, 16D-27D, 34D-37D
051636,000033: 23,3252 00051 S2 # XDC = (XD1 XD2 XD3)
051637,000034: 23,3253 02665 XDC # YDC = (YD1 YD2 YD3)
051638,000035: 23,3254 65325 PDDL PDDL # ZDC = (ZD1 ZD2 ZD3)
051639,000036: 23,3255 06524 HI6ZEROS
051640,000037: 23,3256 02671 XDC +4
051641,000038: 23,3257 55476 DCOMP VDEF
051642,000039: 23,3260 77656 UNIT
051643,000040: 23,3261 14027 STODL ZPRIME # ZP = UNIT(-XD3 0 XD1) = (ZP1 ZP2 ZP3)
051644,000041: 23,3262 00027 ZPRIME
051645,000042:
051646,000043: 23,3263 77742 SR1
051647,000044: 23,3264 14023 STODL SINTH # SIN(IGC) = ZP1
051648,000045: 23,3265 00033 ZPRIME +4
051649,000046: 23,3266 77742 SR1
051650,000047: 23,3267 34021 STCALL COSTH # COS(IGC) = ZP3
051651,000048: 23,3270 47322 ARCTRIG
051652,000049:
051653,000050: 23,3271 16742 STODL IGC # Y GYRO TORQUING ANGLE FRACTION OF REV.
051654,000051: 23,3272 02667 XDC +2
051655,000052: 23,3273 77742 SR1
051656,000053: 23,3274 14023 STODL SINTH # SIN(MGC) = XD2
051657,000054: 23,3275 00027 ZPRIME
051658,000055:
051659,000056: 23,3276 65205 DMP PDDL
051660,000057: 23,3277 02671 XDC +4 # PD00 = (ZP1)(XD3)
051661,000058: 23,3300 00033 ZPRIME +4
051662,000059:
051663,000060: 23,3301 45205 DMP DSU
051664,000061: 23,3302 02665 XDC # MPAC = (ZP3)(XD1)
051665,000062: 23,3303 77626 STADR
051666,000063: 23,3304 43756 STCALL COSTH # COS(MGC) = MPAC - PD00
051667,000064: 23,3305 47322 ARCTRIG
051668,000065: # Page 1247
051669,000066: 23,3306 26744 STOVL MGC # Z GYRO TORQUING ANGLE FRACTION OF REV.
051670,000067: 23,3307 00027 ZPRIME
051671,000068: 23,3310 77641 DOT
051672,000069: 23,3311 02701 ZDC
051673,000070: 23,3312 24021 STOVL COSTH # COS(OGC) = ZP . ZDC
051674,000071: 23,3313 00027 ZPRIME
051675,000072: 23,3314 77641 DOT
051676,000073: 23,3315 02673 YDC
051677,000074: 23,3316 34023 STCALL SINTH # SIN(OGC) = ZP . YDC
051678,000075: 23,3317 47322 ARCTRIG
051679,000076:
051680,000077: 23,3320 36740 STCALL OGC # X GYRO TORQUING ANGLE FRACTION OF REV.
051681,000078: 23,3321 00051 S2
051682,000079:
051683,000080: # Page 1248
051684,000081: # ARCTRIG COMPUTES AN ANGLE GIVEN THE SINE AND COSINE OF THIS ANGLE.
051685,000082:
051686,000083: # THE INPUTS ARE SIN/4 AND COS/4 STORED UP AT SINTH AND COSTH.
051687,000084:
051688,000085: # THE OUTPUT IS THE CALCULATED ANGLE BETWEEN +.5 AND -.5 REVOLUTIONS AND STORED AT THETA. THE OUTPUT IS ALSO
051689,000086: # AVAILABLE AT MPAC.
051690,000087:
051691,000088: 23,3322 51545 ARCTRIG DLOAD ABS # PUSHDOWN 16D-21D
051692,000089: 23,3323 00023 SINTH
051693,000090: 23,3324 50025 DSU BMN
051694,000091: 23,3325 07536 QTSN45 # ABS(SIN/4) - SIN(45)/4
051695,000092: 23,3326 47335 TRIG1 # IF (-45,45) OR (135,-135)
051696,000093:
051697,000094: 23,3327 72545 DLOAD SL1 # (45,135) OR (-135,-45)
051698,000095: 23,3330 00021 COSTH
051699,000096: 23,3331 75326 ACOS SIGN
051700,000097: 23,3332 00023 SINTH
051701,000098: 23,3333 00025 STORE THETA # X = ARCCOS(COS) WITH SIGN(SIN)
051702,000099: 23,3334 77616 RVQ
051703,000100:
051704,000101: 23,3335 72545 TRIG1 DLOAD SL1 # (-45,45) OR (135,-135)
051705,000102: 23,3336 00023 SINTH
051706,000103: 23,3337 77736 ASIN
051707,000104: 23,3340 14025 STODL THETA # X = ARCSIN(SIN) WITH SIGN(SIN)
051708,000105: 23,3341 00021 COSTH
051709,000106: 23,3342 77640 BMN
051710,000107: 23,3343 47346 TRIG2 # IF (135,-135)
051711,000108:
051712,000109: 23,3344 43545 DLOAD RVQ
051713,000110: 23,3345 00025 THETA # X = ARCSIN(SIN) (-45,45)
051714,000111:
051715,000112: 23,3346 75345 TRIG2 DLOAD SIGN # (135,-135)
051716,000113: 23,3347 06522 HIDPHALF
051717,000114: 23,3350 00023 SINTH
051718,000115: 23,3351 77625 DSU
051719,000116: 23,3352 00025 THETA
051720,000117: 23,3353 00025 STORE THETA # X = .5 WITH SIGN(SIN) - ARCSIN(SIN)
051721,000118: 23,3354 77616 RVQ # (+) - (+) OR (-) - (-)
051722,000119:
051723,000120: # Page 1249
051724,000121: # SMNB, NBSM, AND AXISROT, WHICH USED TO APPEAR HERE, HAVE BEEN
051725,000122: # COMBINED IN A ROUTINE CALLED AX*SR*T, WHICH APPEARS AMONG THE POWERED
051726,000123: # FLIGHT SUBROUTINES.
051727,000124:
051728,000125: # Page 1250
051729,000126: # CALCGA COMPUTES THE CDU DRIVING ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION.
051730,000127:
051731,000128: # THE INPUTS ARE 1) THE NAVIGATION BASE COORDINATES REFERRED TO ANY COORDINATE SYSTEM. THE THREE HALF-UNIT
051732,000129: # VECTORS ARE STORED AT XNB, YNB, AND ZNB. 2) THE DESIRED STABLE MEMBER COORDINATES REFERRED TO THE SAME
051733,000130: # COORDINATE SYSTEM ARE STORED AT XSM, YSM, AND ZSM.
051734,000131:
051735,000132: # THE OUTPUTS ARE THE THREE CDU DRIVING ANGLES AND ARE STORED SP AT THETAD, THETAD +1, AND THETAD +2.
051736,000133:
051737,000134: 23,3355 77601 CALCGA SETPD # PUSHDOWN 00-05, 16D-21D, 34D-37D
051738,000135: 23,3356 00001 0
051739,000136: 23,3357 47375 VLOAD VXV
051740,000137: 23,3360 02665 XNB # XNB = OGA (OUTER GIMBAL AXIS)
051741,000138: 23,3361 02651 YSM # YSM = IGA (INNER GIMBAL AXIS)
051742,000139: 23,3362 41456 UNIT PUSH # PD0 = UNIT(OGA X IGA) = MGA
051743,000140:
051744,000141: 23,3363 44041 DOT ITA
051745,000142: 23,3364 02701 ZNB
051746,000143: 23,3365 00051 S2
051747,000144: 23,3366 24021 STOVL COSTH # COS(OG) = MGA . ZNB
051748,000145: 23,3367 00001 0
051749,000146: 23,3370 77641 DOT
051750,000147: 23,3371 02673 YNB
051751,000148: 23,3372 34023 STCALL SINTH # SIN(OG) = MGA . YNB
051752,000149: 23,3373 47322 ARCTRIG
051753,000150: 23,3374 26740 STOVL OGC
051754,000151: 23,3375 00001 0
051755,000152:
051756,000153: 23,3376 50235 VXV DOT # PROVISION FOR MG ANGLE OF 90 DEGREES
051757,000154: 23,3377 02665 XNB
051758,000155: 23,3400 02651 YSM
051759,000156: 23,3401 77752 SL1
051760,000157: 23,3402 24021 STOVL COSTH # COS(MG) = IGA . (MGA X OGA)
051761,000158: 23,3403 02651 YSM
051762,000159: 23,3404 77641 DOT
051763,000160: 23,3405 02665 XNB
051764,000161: 23,3406 34023 STCALL SINTH # SIN(MG) = IGA . OGA
051765,000162: 23,3407 47322 ARCTRIG
051766,000163: 23,3410 02744 STORE MGC
051767,000164:
051768,000165: 23,3411 45246 ABS DSU
051769,000166: 23,3412 07540 .166...
051770,000167: 23,3413 77644 BPL
051771,000168: 23,3414 47433 GIMLOCK1 # IF ANGLE GREATER THAN 60 DEGREES
051772,000169:
051773,000170: 23,3415 50375 CALCGA1 VLOAD DOT
051774,000171: 23,3416 02657 ZSM
051775,000172: 23,3417 00001 0
051776,000173: 23,3420 24021 STOVL COSTH # COS(IG) = ZSM . MGA
051777,000174: 23,3421 02643 XSM
051778,000175: # Page 1251
051779,000176: 23,3422 45441 DOT STADR
051780,000177: 23,3423 43754 STCALL SINTH # SIN(IG) = XSM . MGA
051781,000178: 23,3424 47322 ARCTRIG
051782,000179:
051783,000180: 23,3425 26742 STOVL IGC
051784,000181: 23,3426 02740 OGC
051785,000182: 23,3427 77634 RTB
051786,000183: 23,3430 21621 V1STO2S
051787,000184: 23,3431 34322 STCALL THETAD
051788,000185: 23,3432 00051 S2
051789,000186:
051790,000187: 23,3433 77776 GIMLOCK1 EXIT
051791,000188: 23,3434 05567 TC ALARM
051792,000189: 23,3435 00401 OCT 00401
051793,000190: 23,3436 05504 TC UPFLAG # GIMBAL LOCK HAS OCCURRED
051794,000191: 23,3437 00056 ADRES GLOKFAIL
051795,000192:
051796,000193: 23,3440 06042 TC INTPRET
051797,000194: 23,3441 77650 GOTO
051798,000195: 23,3442 47415 CALCGA1
051799,000196:
051800,000197: # Page 1252
051801,000198: # AXISGEN COMPUTES THE COORDINATES OF ONE COORDINATE SYSTEM REFERRED TO ANOTHER COORDINATE SYSTEM.
051802,000199:
051803,000200: # THE INPUTS ARE 1) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM A STORED AT STARAD. 2) THE STAR2 VECTOR
051804,000201: # REFERRED TO COORDINATE SYSTEM A STORED AT STARAD +6. 3) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM B STORED
051805,000202: # AT LOCATION 6 OF THE VAC AREA. 4) THE STAR2 VECTOR REFERRED TO COORDINATE SYSTEM B STORED AT LOCATION 12D OF
051806,000203: # THE VAC AREA.
051807,000204:
051808,000205: # THE OUTPUT DEFINES COORDINATE SYSTEM A REFERRED TO COORDINATE SYSTEM B. THE THREE HALF-UNIT VECTORS ARE STORED
051809,000206: # AT LOCATIONS XDC, XDC +6, XDC +12D, AND STARAD, STARAD +6, STARAD +12D.
051810,000207:
051811,000208: 23,3443 66370 AXISGEN AXT,1 SSP # PUSHDOWN 00-30D, 34D-37D
051812,000209: 23,3444 02714 STARAD +6
051813,000210: 23,3445 00051 S1
051814,000211: 23,3446 02700 STARAD -6
051815,000212:
051816,000213: 23,3447 77601 SETPD
051817,000214: 23,3450 00001 0
051818,000215: 23,3451 46773 AXISGEN1 VLOAD* VXV* # 06D UA = S1
051819,000216: 23,3452 02723 STARAD +12D,1 # STARAD +00D UB = S1
051820,000217: 23,3453 02731 STARAD +18D,1
051821,000218: 23,3454 77656 UNIT # 12D VA = UNIT(S1 X S2)
051822,000219: 23,3455 06731 STORE STARAD +18D,1 # STARAD +06D VB = UNIT(S1 X S2)
051823,000220: 23,3456 77773 VLOAD*
051824,000221: 23,3457 02723 STARAD +12D,1
051825,000222:
051826,000223: 23,3460 76433 VXV* VSL1
051827,000224: 23,3461 02731 STARAD +18D,1 # 18D WA = UA X VA
051828,000225: 23,3462 06737 STORE STARAD +24D,1 # STARAD +12D WB = UB X VB
051829,000226:
051830,000227: 23,3463 77700 TIX,1
051831,000228: 23,3464 47451 AXISGEN1
051832,000229:
051833,000230: 23,3465 66160 AXC,1 SXA,1
051834,000231: 23,3466 00006 6
051835,000232: 23,3467 00036 30D
051836,000233:
051837,000234: 23,3470 66370 AXT,1 SSP
051838,000235: 23,3471 00022 18D
051839,000236: 23,3472 00051 S1
051840,000237: 23,3473 00006 6
051841,000238:
051842,000239: 23,3474 66374 AXT,2 SSP
051843,000240: 23,3475 00006 6
051844,000241: 23,3476 00052 S2
051845,000242: 23,3477 00002 2
051846,000243:
051847,000244: 23,3500 76720 AXISGEN2 XCHX,1 VLOAD*
051848,000245: 23,3501 00036 30D # X1=-6 X2=+6 X1=-6 X2=+4 X1=-6 X2=+2
051849,000246: 23,3502 00001 0,1
051850,000247:
051851,000248: # Page 1253
051852,000249: 23,3503 62757 VXSC* PDVL* # J=(UA)(UB1) J=(UA)(UB2) J=(UA)(UB3)
051853,000250: 23,3504 75062 STARAD +6,2
051854,000251: 23,3505 00007 6,1
051855,000252: 23,3506 77757 VXSC*
051856,000253: 23,3507 75054 STARAD +12D,2
051857,000254: 23,3510 30031 STOVL* 24D # K=(VA)(VB1) J=(VA)(VB2) J=(VA)(VB3)
051858,000255: 23,3511 00015 12D,1
051859,000256:
051860,000257: 23,3512 53357 VXSC* VAD
051861,000258: 23,3513 75046 STARAD +18D,2 # L=(WA)(WB1) J=(WA)(WB2) J=(WA)(WB3)
051862,000259: 23,3514 76455 VAD VSL1
051863,000260: 23,3515 00031 24D
051864,000261: 23,3516 53520 XCHX,1 UNIT
051865,000262: 23,3517 00036 30D
051866,000263: 23,3520 06707 STORE XDC +18D,1 # XDC = L+J+K YDC = L+J+K ZDC = L+J+K
051867,000264:
051868,000265: 23,3521 77700 TIX,1
051869,000266: 23,3522 47523 AXISGEN3
051870,000267:
051871,000268: 23,3523 77704 AXISGEN3 TIX,2
051872,000269: 23,3524 47500 AXISGEN2
051873,000270:
051874,000271: 23,3525 77775 VLOAD
051875,000272: 23,3526 02665 XDC
051876,000273: 23,3527 26707 STOVL STARAD
051877,000274: 23,3530 02673 YDC
051878,000275: 23,3531 26715 STOVL STARAD +6
051879,000276: 23,3532 02701 ZDC
051880,000277: 23,3533 02723 STORE STARAD +12D
051881,000278:
051882,000279: 23,3534 77616 RVQ
051883,000280:
051884,000281: # Page 1254
051885,000282: 23,3535 05520 26075 QTSN45 2DEC .1768
051886,000283: 23,3537 05252 25253 .166... 2DEC .1666666667
051887,000284:
051888,000285: # Page 1255
051889,000286: # (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