Source Code
![]() |
This source code is very close to the Apollo Guidance Computer software for the
Apollo 13 Lunar module. This revision of the Luminary 131 program is from December
of 1969, whereas there was a later revision in January of 1970, and still another
revision in February, which is the code that flew on the mission.
As far as this transcription is concerned, it was originally from a copy made in 1991 of
a printout from the collection of AGC developer Don Eyles for collector David Craig.
It was subsequently scanned by Gary Neff, reprocessed for online
presentation at the now-discontinued History of Recent Science and Technology (HRST) website
of MIT's Dibner Institute (the full-quality scans being discarded in the process),
and finally transcribed by Ron Burkey for the Virtual AGC Project. Although a
high-quality replacement scan for a completely illegible page was later provided by Gary
Neff, the reduced legibility of the reprocessed HRST posting nevertheless caused many
errors to be introduced into the transcription. Accordingly, a second scan of the same physical
printout was made in 2017 for the Virtual AGC Project's collection at the Internet Archive,
and used to correct the transcription errors. All of the scanned materials mentioned,
as well as other Luminary 131 related material, are available online.
Don Eyles apprently made additional hand-written notes in printout between 1991 and 2017,
so the two scans are not identical in that respect. The page-headings in the printout read, in part:GAP: ASSEMBLE REVISION 131 OF AGC PROGRAM LUMINARY BY NASA 2021112-091 17:53 DEC. 19, 1969Note that the date is the date the printout was made, not the date on which the program revision was released, although these happen to be very close together. |
062204,000002: ## Copyright: Public domain.
062205,000003: ## Filename: TRIM_GIMBAL_CNTROL_SYSTEM.agc
062206,000004: ## Purpose: A section of Luminary 1C, revision 131.
062207,000005: ## It is part of the source code for the Lunar Module's (LM)
062208,000006: ## Apollo Guidance Computer (AGC) for Apollo 13.
062209,000007: ## This file is intended to be a faithful transcription, except
062210,000008: ## that the code format has been changed to conform to the
062211,000009: ## requirements of the yaYUL assembler rather than the
062212,000010: ## original YUL assembler.
062213,000011: ## Reference: pp. 1464-1476
062214,000012: ## Contact: Ron Burkey <info@sandroid.org>.
062215,000013: ## Website: www.ibiblio.org/apollo/index.html
062216,000014: ## Mod history: 06/08/03 RSB. Began transcribing.
062217,000015: ## 05/14/05 RSB Corrected website reference above.
062218,000016: ## 2010-10-25 JL Indentation fixes.
062219,000017: ## 2017-01-06 RSB Page numbers now agree with those on the
062220,000018: ## original hardcopy, as opposed to the PDF page
062221,000019: ## numbers in 1701.pdf.
062222,000020: ## 2017-02-28 RSB Proofed comment text using octopus/ProoferComments.
062223,000021: ## 2017-03-14 RSB Comment-text fixes noted in proofing Luminary 116.
062224,000022:
![]() |
Page 1464 |
062226,000024: 21,3076 BANK 21
062227,000025: 21,3076 E6,1450 EBANK= QDIFF
062228,000026: 21,2000 SETLOC DAPS4
062229,000027: 21,2000 BANK
062230,000028:
062231,000029: 21,3076 COUNT* $$/DAPGT
062232,000030:
062233,000031: # CONTROL REACHES THIS POINT UNDER EITHER OF THE FOLLOWING TWO CONDITIONS ONCE THE DESCENT ENGINE AND THE DIGITAL
062234,000032: # AUTOPILOT ARE BOTH ON:
062235,000033: # A) THE TRIM GIMBAL CONTROL LAW WAS ON DURING THE PREVIOUS Q,R-AXIS TIME5 INTERRUPT (OR THE DAPIDLER
062236,000034: # INITIALIZATION WAS SET FOR TRIM GIMBAL CONTROL AND THIS IS THE FIRST PASS), OR
062237,000035: # B) THE Q,R-AXES RCS AUTOPILOT DETERMINED THAT THE VEHICLE WAS ENTERING (OR HAD JUST ENTERED) A COAST
062238,000036: # ZONE WITH A SMALL OFFSET ANGULAR ACCELERATION.
062239,000037: # GTS IS THE ENTRY TO THE GIMBAL TRIM SYSTEM FOR CONTROLLING ATTITUDE ERRORS AND RATES AS WELL AS ACCELERATIONS.
062240,000038:
062241,000039: 21,3076 37752 GTS CAF NEGONE # MAKE THE NEXT PASS THROUGH THE DAP BE
062242,000040: 21,3077 55630 TS COTROLER # THROUGH RCS CONTROL,
062243,000041: 21,3100 34751 CAF FOUR # AND ENSURE THAT IT IS NOT A SKIP.
062244,000042: 21,3101 55534 TS SKIPU
062245,000043: 21,3102 55535 TS SKIPV
062246,000044:
062247,000045: 21,3103 34752 CAF TWO
062248,000046: 21,3104 55632 TS INGTS # SET INDICATOR OF GTS CONTROL POSITIVE.
062249,000047: 21,3105 55631 TS QGIMTIMR # SET TIMERS TO 200 MSEC TO AVOID BOTH
062250,000048: 21,3106 55633 TS RGIMTIMR # RUNAWAY AND INTERFERENCE BY NULLING.
062251,000049:
062252,000050: # THE DRIVE SETTING ALGORITHM
062253,000051: # DEL = SGN(OMEGA + ALPHA*ABS(ALPHA)/(2*K))
062254,000052: # 2 1/2 2 3/2
062255,000053: # NEGUSUM = ERROR*K + ALPHA*(DEL*OMEGA + ALPHA /(3*K)) + DEL*K (DEL*OMEGA + ALPHA /(2*K))
062256,000054: # DRIVE = -SGN(NEGUSUM)
062257,000055:
062258,000056: 21,3107 30021 CA SR # SAVE THE SR. SHIFT IT LEFT TO CORRECT
062259,000057: 21,3110 60000 AD A # FOR THE RIGHT SHIFT DUE TO EDITING.
062260,000058: 21,3111 55505 TS SAVESR
062261,000059:
062262,000060: 21,3112 34752 GTSGO+DN CAF TWO # SET INDEXER FOR R-AXIS CALCULATIONS.
062263,000061: 21,3113 13115 TCF GOQTRIMG +1
062264,000062:
062265,000063: 21,3114 34755 GOQTRIMG CAF ZERO # SET INDEXER FOR Q-AXIS CALCULATIONS
062266,000064: 21,3115 55747 TS QRCNTR
062267,000065:
062268,000066: 21,3116 51747 INDEX QRCNTR # AOS SCALED AT PI/2
062269,000067: 21,3117 31536 CA AOSQ
062270,000068: 21,3120 00006 EXTEND
062271,000069: 21,3121 74752 MP BIT2 # RESCALE AOS TO PI/4
![]() |
Page 1465 |
062273,000071: 21,3122 00006 EXTEND
062274,000072: 21,3123 13127 BZF GTSQAXIS -3 # USE FULL SCALE FOR LARGER AOS ESTIMATES.
062275,000073:
062276,000074: 21,3124 50000 INDEX A
062277,000075: 21,3125 44734 CS LIMITS # LIMITS +1 CONTAINS NEGMAX.
062278,000076: 21,3126 56001 XCH L # LIMITS -1 CONTAINS POSMAX.
062279,000077:
062280,000078: 21,3127 11747 CCS QRCNTR # PICK UP RATE FOR THIS AXIS. RATE CELLS
062281,000079: 21,3130 50000 INDEX A # ARE ADJACENT, NOT SEPARATED. AT PI/4
062282,000080: 21,3131 31436 CA EDOTQ
062283,000081: 21,3132 53743 GTSQAXIS DXCH WCENTRAL
062284,000082:
062285,000083: 21,3133 51747 INDEX QRCNTR # COLLECT K FOR THIS AXIS
062286,000084: 21,3134 31504 CA KQ
062287,000085: 21,3135 55740 TS KCENTRAL
062288,000086:
062289,000087: 21,3136 00006 EXTEND # CONTROL AUTHORITY ZERO. AVOID DRIVING
062290,000088: 21,3137 13575 BZF POSDRIVE +1 # ENGINE BELL TO THE STOPS.
062291,000089:
062292,000090: 21,3140 51747 INDEX QRCNTR # QDIFF, RDIFF ARE STORED IN D.P.
062293,000091: 21,3141 31450 CAE QDIFF
062294,000092:
062295,000093: 21,3142 00006 ALGORTHM EXTEND # Q(R)DIFF IS THETA (ERROR) SCALED AT PI.
062296,000094: 21,3143 71740 MP KCENTRAL # FORM K*ERROR AT PI(2)/2(8), IN D.P.
062297,000095: 21,3144 23736 LXCH K2THETA
062298,000096: 21,3145 00006 EXTEND
062299,000097: 21,3146 74747 MP BIT5 # RESCALE TO 4*PI(2)
062300,000098: 21,3147 53737 DXCH K2THETA
062301,000099: 21,3150 00006 EXTEND
062302,000100: 21,3151 74747 MP BIT5 # FIRST TERM OF NEGUSUM IN K2THETA.
062303,000101: 21,3152 27737 ADS K2THETA +1 # NO CARRY NEEDED D.P. AT 4*PI(2)
062304,000102:
062305,000103: 21,3153 41743 CS ACENTRAL # FORM ALPHA(2)/(2*K) AT 16*PI, IN D.P.,
062306,000104: 21,3154 00006 EXTEND # LIMITING QUOTIENT TO AVOID OVERFLOW.
062307,000105: 21,3155 74736 MP BIT14 # -ALPHA/2 IN A, SCALED AT PI/4
062308,000106: 21,3156 00006 EXTEND
062309,000107: 21,3157 71743 MP ACENTRAL # -ALPHA(2)/2 IN A,L, SCALED AT PI(2)/16
062310,000108: 21,3160 61740 AD KCENTRAL
062311,000109: 21,3161 00006 EXTEND
062312,000110: 21,3162 63177 BZMF HUGEQUOT # K-ALPHA(2)/2 SHOULD BE PNZ FO DIVISION
062313,000111:
062314,000112: 21,3163 00006 EXTEND
062315,000113: 21,3164 40001 DCS A # ALPHA(2)/2 - K
062316,000114: 21,3165 61740 AD KCENTRAL
062317,000115: 21,3166 00006 EXTEND
062318,000116: 21,3167 11740 DV KCENTRAL # HIGH ORDER OF QUOTIENT.
062319,000117: 21,3170 57745 XCH A2CNTRAL
062320,000118: 21,3171 30001 CA L # SHIFT UP THE REMAINDER.
062321,000119: 21,3172 22007 LXCH 7 # ZERO LOW-ORDER DIVIDEND.
062322,000120: 21,3173 00006 EXTEND
![]() |
Page 1466 |
062324,000122: 21,3174 11740 DV KCENTRAL
062325,000123: 21,3175 57746 XCH A2CNTRAL +1 # QUOTIENT STORED AT 16*PI, D.P.
062326,000124: 21,3176 13202 TCF HAVEQUOT
062327,000125:
062328,000126: 21,3177 34733 HUGEQUOT CA POSMAX
062329,000127: 21,3200 54001 TS L
062330,000128: 21,3201 53746 DXCH A2CNTRAL # LIMITED QUOTIENT STORED AT 16*PI, D.P.
062331,000129:
062332,000130: 21,3202 31742 HAVEQUOT CA WCENTRAL
062333,000131: 21,3203 00006 EXTEND
062334,000132: 21,3204 74743 MP BIT9 # RESCALE OMEGA AT 16*PI IN D.P.
062335,000133: 21,3205 53742 DXCH K2CNTRAL # LOWER WORD OVERLAYS OMEGA IN WCENTRAL
062336,000134:
062337,000135: 21,3206 00006 EXTEND
062338,000136: 21,3207 31742 DCA K2CNTRAL
062339,000137: 21,3210 53751 DXCH FUNCTION
062340,000138:
062341,000139: 21,3211 31743 CA ACENTRAL # GET ALPHA*ABS(ALPHA)/(2*K)
062342,000140: 21,3212 00006 EXTEND
062343,000141: 21,3213 63217 BZMF +4
062344,000142:
062345,000143: 21,3214 00006 EXTEND
062346,000144: 21,3215 31746 DCA A2CNTRAL
062347,000145: 21,3216 13221 TCF +3
062348,000146:
062349,000147: 21,3217 00006 EXTEND
062350,000148: 21,3220 41746 DCS A2CNTRAL
062351,000149:
062352,000150: 21,3221 21751 DAS FUNCTION # OMEGA + ALPHA*ABS(ALPHA)/2*K) AT 16*PI
062353,000151:
062354,000152: 21,3222 11750 CCS FUNCTION # DEL = +1 FOR FUNCT1 GREATER THAN ZERO.
062355,000153: 21,3223 13227 TCF POSFNCT1 # OTHERWISE DEL = -1
062356,000154: 21,3224 13226 TCF +2
062357,000155: 21,3225 13231 TCF NEGFNCT1
062358,000156:
062359,000157: 21,3226 11751 CCS FUNCTION +1 # USE LOW ORDER WORD SINCE HIGH IS ZERO
062360,000158: 21,3227 34753 POSFNCT1 CAF BIT1
062361,000159: 21,3230 13232 TCF +2
062362,000160: 21,3231 44753 NEGFNCT1 CS BIT1
062363,000161: 21,3232 55744 TS DEL
062364,000162:
062365,000163: 21,3233 11744 CCS DEL # REPLACE OMEGA BY DEL*OMEGA
062366,000164: 21,3234 13246 TCF FUNCT2 # POSITIVE DEL VALUE. PROCEED.
062367,000165: 21,3235 13237 TCF DEFUNCT
062368,000166: 21,3236 13243 TCF NEGFNCT2
062369,000167:
062370,000168: 21,3237 55741 DEFUNCT TS K2CNTRAL
062371,000169: 21,3240 55742 TS K2CNTRAL +1
062372,000170: 21,3241 13246 TCF FUNCT2
062373,000171:
![]() |
Page 1467 |
062375,000173: 21,3242 65252 NEG1/3 DEC -.33333
062376,000174:
062377,000175: 21,3243 00006 NEGFNCT2 EXTEND
062378,000176: 21,3244 41742 DCS K2CNTRAL
062379,000177: 21,3245 53742 DXCH K2CNTRAL
062380,000178:
062381,000179: 21,3246 00006 FUNCT2 EXTEND
062382,000180: 21,3247 31746 DCA A2CNTRAL
062383,000181: 21,3250 21742 DAS K2CNTRAL # DEL*OMEGA + ALPHA(2)/(2*K) AT 16*PI, D.P.
062384,000182:
062385,000183: 21,3251 31745 FUNCT3 CA A2CNTRAL
062386,000184: 21,3252 00006 EXTEND
062387,000185: 21,3253 73242 MP NEG1/3
062388,000186: 21,3254 53746 DXCH A2CNTRAL
062389,000187: 21,3255 30001 CA L
062390,000188: 21,3256 00006 EXTEND
062391,000189: 21,3257 73242 MP NEG1/3
062392,000190: 21,3260 27746 ADS A2CNTRAL +1
062393,000191: 21,3261 54001 TS L
062394,000192: 21,3262 13264 TCF +2 # A2CNTRAL NOW CONTAINS -ALPHA(2)/(6*K),
062395,000193: 21,3263 27745 ADS A2CNTRAL # SCALED AT 16*PI, IN D.P.
062396,000194:
062397,000195: 21,3264 00006 EXTEND
062398,000196: 21,3265 31742 DCA K2CNTRAL # DEL*OMEGA + ALPHA(2)/(3*K) IN A2CNTRAL,
062399,000197: 21,3266 21746 DAS A2CNTRAL # SCALED AT 16*PI, D.P.
062400,000198:
062401,000199: 21,3267 31745 CA A2CNTRAL
062402,000200: 21,3270 00006 EXTEND
062403,000201: 21,3271 71743 MP ACENTRAL
062404,000202: 21,3272 21737 DAS K2THETA
062405,000203: 21,3273 31746 CA A2CNTRAL +1
062406,000204: 21,3274 00006 EXTEND
062407,000205: 21,3275 71743 MP ACENTRAL # ACENTRAL MAY NOW BE OVERLAID.
062408,000206: 21,3276 27737 ADS K2THETA +1
062409,000207: 21,3277 54001 TS L
062410,000208: 21,3300 13302 TCF +2 # TWO TERMS OF NEGUSUM ACCUMULATED, SO FAR
062411,000209: 21,3301 27736 ADS K2THETA # SCALED AT 4*PI(2), IN D.P.
062412,000210:
062413,000211: 21,3302 31741 GETROOT CA K2CNTRAL # K*(DEL*OMEGA + ALPHA(2)/(2*K)) IS THE
062414,000212: 21,3303 00006 EXTEND # TERM FOR WHICH A SQUARE ROOT IS NEEDED.
062415,000213: 21,3304 71740 MP KCENTRAL # K AT PI/2(8)
062416,000214: 21,3305 53751 DXCH FUNCTION
062417,000215: 21,3306 31742 CA K2CNTRAL +1
062418,000216: 21,3307 00006 EXTEND
062419,000217: 21,3310 71740 MP KCENTRAL
062420,000218: 21,3311 27751 ADS FUNCTION +1
062421,000219: 21,3312 54001 TS L
062422,000220: 21,3313 13315 TCF +2
062423,000221: 21,3314 27750 ADS FUNCTION # DESIRED TERM IN FUNCTION, AT PI(2)/16
![]() |
Page 1468 |
062425,000223: 21,3315 11744 CCS DEL
062426,000224: 21,3316 13523 TCF RSTOFGTS
062427,000225: 21,3317 13565 TCF NEGUSUM
062428,000226: 21,3320 13322 TCF NEGATE
062429,000227: 21,3321 13565 TCF NEGUSUM
062430,000228:
062431,000229: 21,3322 00006 NEGATE EXTEND
062432,000230: 21,3323 41742 DCS K2CNTRAL
062433,000231: 21,3324 53742 DXCH K2CNTRAL
062434,000232: 21,3325 13523 TCF RSTOFGTS
062435,000233:
062436,000234: 16,3741 BANK 16
062437,000235: 16,3741 E6,1501 EBANK= NEGUQ
062438,000236: 16,2000 SETLOC DAPS1
062439,000237: 16,2000 BANK
062440,000238:
062441,000239: # THE WRCHN12 SUBROUTINE SETS BITS 9,10,11,12 OF CHANNEL 12 ON THE BASIS OF THE CONTENTS OF NEGUQ,NEGUR WHICH ARE
062442,000240: # THE NEGATIVES OF THE DESIRED ACCELERATION CHANGES. ACDT+C12 SETS Q(R)ACCDOT TO REFLECT THE NEW DRIVES.
062443,000241:
062444,000242: # WARNING: ACDT+C12 AND WRCHN12 MUST BE CALLED WITH INTERRUPT INHIBITED.
062445,000243:
062446,000244: 16,3741 07400 BGIM OCTAL 07400
062447,000245: 16,3742 0066 CHNL12 EQUALS ITEMP6
062448,000246: 16,3742 41501 ACDT+C12 CS NEGUQ
062449,000247: 16,3743 00006 EXTEND # GIMBAL DRIVE REQUESTS.
062450,000248: 16,3744 71507 MP ACCDOTQ
062451,000249: 16,3745 23510 LXCH QACCDOT
062452,000250: 16,3746 41503 CS NEGUR
062453,000251: 16,3747 00006 EXTEND
062454,000252: 16,3750 71511 MP ACCDOTR
062455,000253: 16,3751 23512 LXCH RACCDOT
062456,000254:
062457,000255: 16,3752 11501 CCS NEGUQ
062458,000256: 16,3753 34742 CAF BIT10
062459,000257: 16,3754 13756 TCF +2
062460,000258: 16,3755 34743 CAF BIT9
062461,000259: 16,3756 54066 TS CHNL12
062462,000260:
062463,000261: 16,3757 11503 CCS NEGUR
062464,000262: 16,3760 34740 CAF BIT12
062465,000263: 16,3761 13763 TCF +2
062466,000264: 16,3762 34741 CAF BIT11
062467,000265: 16,3763 26066 ADS CHNL12 # (STORED RESULT NOT USED AT PRESENT)
062468,000266:
062469,000267: 16,3764 43741 CS BGIM
062470,000268: 16,3765 00006 EXTEND
062471,000269: 16,3766 02012 RAND CHAN12
062472,000270: 16,3767 60066 AD CHNL12
062473,000271: 16,3770 00006 EXTEND
062474,000272: 16,3771 01012 WRITE CHAN12
![]() |
Page 1469 |
062476,000274: 16,3772 44747 CS CALLGMBL # TURN OFF REQUEST FOR ACDT+C12 EXECUTION.
062477,000275: 16,3773 71262 MASK RCSFLAGS
062478,000276: 16,3774 55262 TS RCSFLAGS
062479,000277:
062480,000278: 16,3775 00002 TC Q # RETURN TO CALLER.
062481,000279:
062482,000280: 21,3326 BANK 21
062483,000281: 21,3326 E6,1450 EBANK= QDIFF
062484,000282: 21,2000 SETLOC DAPS4
062485,000283: 21,2000 BANK
062486,000284:
![]() |
Page 1470 |
062488,000286: # SUBROUTINE TIMEGMBL: MOD 0, OCTOBER 1967, CRAIG WORK
062489,000287:
062490,000288: # TIMEGMBL COMPUTES THE DRIVE TIME NEEDED FOR THE TRIM GIMBAL TO POSITION THE DESCENT ENGINE NOZZLE SO AS TO NULL
062491,000289: # THE OFFSET ANGULAR ACCELERATION ABOUT THE Q (OR R) AXIS. INSTEAD OF USING AOSQ(R), TIMEGMBL USES .4*AOSQ(R),
062492,000290: # SCALED AT PI/8. FOR EACH AXIS, THE DRIVE TIME IS COMPUTED AS ABS(ALPHA/ACCDOT). A ZERO
062493,000291: # ALPHA OR ACCDOT OR A ZERO QUOTIENT TURNS OFF THE GIMBAL DRIVE IMMEDIATELY. OTHERWISE, THE GIMBAL IS TURNED ON
062494,000292: # DRIVING IN THE CORRECT DIRECTION. THE Q(R)GIMTIMR IS SET TO TERMINATE THE DRIVE AND Q(R)ACCDOT
062495,000293: # IS STORED TO REFLECT THE NEW ACCELERATION DERIVATIVE. NEGUQ(R) WILL CONTAIN +1,+0,-1 FOR A Q(R)ACCDOT VALUE
062496,000294: # WHICH IS NEGATIVE, ZERO, OR POSITIVE.
062497,000295:
062498,000296: # INPUTS: AOSQ,AOSR, SCALED AT P1/2, AND ACCDOTQ, ACCDOTR AT PI/2(7). PI/2(7).
062499,000297:
062500,000298: # OUTPUTS: NEW GIMBAL DRIVE BITS IN CHANNEL 12, NEGUQ, NEGUR, QACCDOT AND RACCDOT, THE LAST SCALED AT PI/2(7).
062501,000299: # Q(R)GIMTIMR WILL BE SET TO TIME AND TERMINATE GIMBAL DRIVE(S)
062502,000300:
062503,000301: # DEBRIS: A, L, Q, ITEMPS 2, 3, 6, RUPTREG2 AND ACDT+C12 DEBRIS.
062504,000302:
062505,000303: # EXITS: VIA TC Q.
062506,000304:
062507,000305: # ALARMS, ABORTS, : NONE
062508,000306:
062509,000307: # SUBROUTINES: ACDT+C12, IBNKCALL
062510,000308:
062511,000309: # WARNING: THIS SUBROUTINE WRITES INTO CHANNEL 12 AND USES THE ITEMPS. THEREFORE IT MAY ONLY BE CALLED WITH
062512,000310: # INTERRUPT INHIBITED.
062513,000311:
062514,000312: # ERASABLE STORAGE CONFIGURATION (NEEDED BY THE INDEXING METHODS):
062515,000313: # NEGUQ ERASE +2 NEGATIVE OF Q-AXIS GIMBAL DRIVE
062516,000314: # (SPWORD) EQUALS NEGUQ +1 ANY S.P. ERASABLE NUMBER, NOW THRSTCMD
062517,000315: # NEGUR EQUALS NEGUQ +2 NEGATIVE OF R-AXIS GIMBAL DRIVE
062518,000316: # ACCDOTQ ERASE +2 Q-JERK TERM SCALED AT PI/2(7) RAD/SEC(3)
062519,000317: # (SPWORD) EQUALS ACCDOTQ +1 ANY S.P. ERASABLE NUMBER NOW QACCDOT
062520,000318: # ACCDOTR EQUALS ACCDOTQ +2 R-JERK TERM SCALED AT PI/2(7) RAD/SEC(3)
062521,000319: # ACCDOTQ, ACCDOTR ARE MAGNITUDES.
062522,000320: # AOSQ ERASE +4 Q-AXIS ACC., D.P. AT PI/2 R/SEC(2)
062523,000321: # AOSR EQUALS AOSQ +2 R-AXIS ACCELERATION SCALED AT PI/2 R/S2
062524,000322:
062525,000323: 21,3326 0066 QRNDXER EQUALS ITEMP6
062526,000324: 21,3326 23146 OCT23146 OCTAL 23146 # DECIMAL .6
062527,000325: 21,3327 0063 NZACCDOT EQUALS ITEMP3
062528,000326:
062529,000327: 21,3327 34753 TIMEGMBL CAF ONE # INITIALIZE ALLOWGTS.
062530,000328: 21,3330 55502 TS ALLOWGTS
062531,000329:
062532,000330: 21,3331 34752 CAF TWO # SET UP LOOP FOR R AXIS.
062533,000331: 21,3332 22002 LXCH Q # SAVE RETURN ADDRESS.
062534,000332: 21,3333 22071 LXCH RUPTREG2
![]() |
Page 1471 |
062536,000334: 21,3334 13336 TCF +2
062537,000335: 21,3335 34755 TIMQGMBL CAF ZERO # NOW DO THE Q-AXIS
062538,000336: 21,3336 54066 TS QRNDXER
062539,000337: 21,3337 50066 INDEX QRNDXER
062540,000338: 21,3340 31507 CA ACCDOTQ # ACCDOT IS PRESUMED TO BE AT PI/2(7).
062541,000339: 21,3341 00006 EXTEND
062542,000340: 21,3342 63412 BZMF TGOFFNOW # IS ACCDOT LESS THAN OR EQUAL TO 0?
062543,000341: 21,3343 54063 TS NZACCDOT # NO. STORE NON-ZERO, POSITIVE ACCDOT.
062544,000342:
062545,000343: 21,3344 50066 ALPHATRY INDEX QRNDXER
062546,000344: 21,3345 41536 CS AOSQ
062547,000345: 21,3346 00006 EXTEND
062548,000346: 21,3347 13412 BZF TGOFFNOW # IS ALPHA ZERO?
062549,000347:
062550,000348: 21,3350 54002 TS Q # SAVE A COPY OF -AOS.
062551,000349: 21,3351 00006 EXTEND # NO. RESCALE FOR TIMEGMBL USE.
062552,000350: 21,3352 73326 MP OCT23146 # OCTAL 23146 IS DECIMAL .6
062553,000351: 21,3353 60002 AD Q # -1.6*AOS AT PI/2 = -.4*AOS AT PI/8.
062554,000352: 21,3354 54001 TS L # WAS THERE OVERFLOW?
062555,000353: 21,3355 13362 TCF SETNEGU # NO. COMPUTE DRIVE TIME.
062556,000354:
062557,000355: 21,3356 40000 CS A # RECOVER -SGN(AOS) IN THE A REGISTER.
062558,000356: 21,3357 50066 INDEX QRNDXER # YES. START DRIVE WITHOUT WAITLIST.
062559,000357: 21,3360 57501 XCH NEGUQ
062560,000358: 21,3361 13416 TCF NOTALLOW # KNOCK DOWN THE ALLOWGTS FLAG.
062561,000359:
062562,000360: 21,3362 00006 SETNEGU EXTEND
062563,000361: 21,3363 63370 BZMF POSALPH
062564,000362:
062565,000363: 21,3364 40000 COM
062566,000364: 21,3365 54062 TS ITEMP2 # STORE -ABS(.4*AOS) SCALED AT PI/8.
062567,000365: 21,3366 44753 CS BIT1
062568,000366: 21,3367 13372 TCF POSALPH +2
062569,000367: 21,3370 54062 POSALPH TS ITEMP2 # STORE -ABS(.4*AOS) SCALED AT PI/8.
062570,000368: 21,3371 34753 CA BIT1
062571,000369: 21,3372 50066 +2 INDEX QRNDXER # SGN(AOS) INTO NEGU
062572,000370: 21,3373 55501 TS NEGUQ # STORE SGN(APLHA) AS NEGU
062573,000371:
062574,000372: 21,3374 30063 CA NZACCDOT
062575,000373: 21,3375 00006 EXTEND
062576,000374: 21,3376 74740 MP BIT12 # 2*ACCDOT, SCALED AT PI/8.
062577,000375: 21,3377 60062 AD ITEMP2 # -ABS(ALPHA) + 2*ACCDOT, AT PI/8.
062578,000376: 21,3400 00006 EXTEND
062579,000377: 21,3401 63416 BZMF NOTALLOW # IS DRIVE TIME MORE THAN TWO SECONDS?
062580,000378: 21,3402 40062 CS ITEMP2 # NO. COMPUTE DRIVE TIME.
062581,000379: 21,3403 00006 EXTEND # ABS(ALPHA) AT PI/8.
062582,000380: 21,3404 73437 MP OCT00240 # DECIMAL 10/1024
062583,000381: 21,3405 00006 EXTEND # QUOTIENT IS DRIVE TIME AT WAITLIST.
062584,000382: 21,3406 10063 DV NZACCDOT # ABS(ALPHA)/ACCDOT AT 2(14)/100
![]() |
Page 1472 |
062586,000384: 21,3407 00006 EXTEND
062587,000385: 21,3410 13412 BZF TGOFFNOW # DRIVE TIME MUST BE GREATER THAN ZERO.
062588,000386:
062589,000387: 21,3411 13424 TCF DRIVEON
062590,000388:
062591,000389: 21,3412 34755 TGOFFNOW CAF ZERO # TURN OFF GIMBAL NOW.
062592,000390: 21,3413 50066 INDEX QRNDXER
062593,000391: 21,3414 55501 TS NEGUQ
062594,000392:
062595,000393: 21,3415 13426 TCF DONEYET
062596,000394:
062597,000395: 21,3416 36010 NOTALLOW CAF OCT31
062598,000396: 21,3417 50066 INDEX QRNDXER
062599,000397: 21,3420 55631 TS QGIMTIMR
062600,000398: 21,3421 34755 CAF ZERO # DRIVE TIME IS MORE THAN 2 SECONDS, SO
062601,000399: 21,3422 55502 TS ALLOWGTS # DO NOT PERMIT FURTHER GTS ATTITUDE-RATE
062602,000400: # CONTROL UNTIL AOSTASK APPROVES.
062603,000401: 21,3423 13426 TCF DONEYET # NO WAITLIST CALL IS MADE.
062604,000402:
062605,000403: 21,3424 50066 DRIVEON INDEX QRNDXER
062606,000404: 21,3425 55631 TS QGIMTIMR # CHOOSE Q OR R AXIS.
062607,000405:
062608,000406: 21,3426 10066 DONEYET CCS QRNDXER
062609,000407: 21,3427 13335 TCF TIMQGMBL
062610,000408:
062611,000409: 21,3430 52073 DXCH RUPTREG3 # PROTECT IBNKCALL ERASABLES. ACDT+C12
062612,000410: 21,3431 52063 DXCH ITEMP2 # LEAVES ITEMPS2,3 ALONE.
062613,000411:
062614,000412: 21,3432 04674 TC IBNKCALL # TURN OF CHANNEL BITS, SET Q(R)ACCDOTS.
062615,000413: 21,3433 35742 CADR ACDT+C12
062616,000414:
062617,000415: 21,3434 52063 DXCH ITEMP2 # RESTORE ERASABLES FOR IBNKCALL.
062618,000416: 21,3435 52073 DXCH RUPTREG3
062619,000417:
062620,000418: 21,3436 00071 TC RUPTREG2 # RETURN TO CALLER.
062621,000419:
062622,000420: 21,3437 00240 OCT00240 OCTAL 00240 # DECIMAL 10/1024
062623,000421:
![]() |
Page 1473 |
062625,000423: # THE FOLLOWING SECTION IS A CONTINUATION OF THE TRIM GIMBAL CONTROL FROM THE LAST GTS ENTRY. THE QUANTITY NEGUSUM
062626,000424: # IS COMPUTED FOR EACH AXIS (Q,R), .707*DEL*FUNCTION(3/2) + K2THETA = NEGUSUM. NEW DRIVES ARE ENTERED TO CH 12.
062627,000425:
062628,000426: # THE SUBROUTINE GTSQRT ACCEPTS A DOUBLE PRECISION VALUE IN FUNCTION, FUNCTION +1 AND RETURNS A SINGLE-PRECISION
062629,000427: # SQUARE ROOT OF THE FOURTEEN MOST SIGNIFICANT BITS OF THE ARGUMENT. ALSO, THE CELL SHFTFLAG CONTAINS A BINARY
062630,000428: # EXPONENT S, SUCH THAT THE SQUARE ROOT (RETURNED IN THE A REGISTER) MUST BE SHIFTED RIGHT (MULTIPLIED BY 2 TO THE
062631,000429: # POWER (-S)) IN ORDER TO BE THE TRUE SQUARE ROOT OF THE FOURTEEN MOST SIGNIFICANT BITS OF FUNCTION, FUNCTION +1.
062632,000430: # SQUARE ROOT ERROR IS NOT MORE THAN 2 IN THE 14TH SIGNIFICANT BIT. CELLS CLOBBERED ARE A, L, SHFTFLAG, ININDEX,
062633,000431: # HALFARG, SCRATCH, SR, FUNCTION, FUNCTION +1. GTSQRT IS CALLED BY TC GTSQRT AND RETURNS VIA TC Q OR TC FUNCTION +1.
062634,000432: # ZERO OR NEGATIVE ARGUMENTS YIELD ZERO FOR SQUARE ROOTS.
062635,000433:
062636,000434: 21,3440 11750 GTSQRT CCS FUNCTION
062637,000435: 21,3441 13457 TCF GOODARG # FUNCTION IS POSITIVE. TAKE SQUARE ROOT.
062638,000436: 21,3442 13444 TCF +2 # HIGH ORDER WORD IS ZERO. TRY THE LOWER.
062639,000437: 21,3443 13450 TCF ZEROOT # NEGATIVE. USE ZERO FOR 1/2 POWER.
062640,000438:
062641,000439: 21,3444 31751 CA FUNCTION +1
062642,000440: 21,3445 00006 EXTEND
062643,000441: 21,3446 63450 BZMF ZEROOT
062644,000442:
062645,000443: 21,3447 13453 TCF ZEROHIGH # PROCEED.
062646,000444: 21,3450 34755 ZEROOT CA ZERO
062647,000445: 21,3451 55740 TS SHFTFLAG
062648,000446: 21,3452 00002 TC Q
062649,000447:
062650,000448: 21,3453 57750 ZEROHIGH XCH FUNCTION # 14 MOST SIGNIFICANT BITS ARE IN THE
062651,000449: 21,3454 57751 XCH FUNCTION +1 # LOWER WORD. EXCHANGE THEM.
062652,000450: 21,3455 34757 CA SEVEN
062653,000451: 21,3456 13460 TCF GOODARG +1
062654,000452:
062655,000453: 21,3457 34755 GOODARG CA ZERO
062656,000454: 21,3460 55740 TS SHFTFLAG
062657,000455: 21,3461 35741 CA TWELVE # INITIALIZE THE SCALING LOOP.
062658,000456: 21,3462 55743 TS ININDEX
062659,000457: 21,3463 13472 TCF SCALLOOP
062660,000458:
062661,000459: 21,3464 31750 SCALSTRT CA FUNCTION
062662,000460: 21,3465 13506 TCF SCALDONE
062663,000461:
062664,000462: 21,3466 37751 MULBUSH CA NEG2 # IF ARG IS NOT LESS THAN 1/4, INDEX IS
062665,000463: 21,3467 27743 ADS ININDEX # ZERO, INDICATING NO SHIFT NEEDED.
062666,000464: 21,3470 00006 EXTEND # BRANCH IF ARG IS NOT LESS THAN 1/4.
062667,000465: 21,3471 63464 BZMF SCALSTRT # OTHERWISE COMPARE ARG WITH A REFERENCE
062668,000466: # WHICH IS 4 TIMES LARGER THAN THE LAST.
062669,000467: 21,3472 41750 SCALLOOP CS FUNCTION
062670,000468: 21,3473 51743 INDEX ININDEX
062671,000469: 21,3474 64735 AD BIT15 # REFERENCE MAGNITUDE LESS OR EQUAL TO 1/4
062672,000470: 21,3475 00006 EXTEND
062673,000471: 21,3476 63466 BZMF MULBUSH # IF ARG IS NOT LESS THAN REFERENCE, GO
062674,000472: # AROUND THE MULBERRY BUSH ONCE MORE.
![]() |
Page 1474 |
062676,000474: 21,3477 51743 INDEX ININDEX
062677,000475: 21,3500 34735 CA BIT15 # THIS IS THE SCALE MAGNITUDE
062678,000476: 21,3501 57746 XCH HALFARG # 2**(-ININDEX) IS THE SHIFT DIVISOR.
062679,000477: 21,3502 00006 EXTEND # RESCALE ARGUMENT.
062680,000478: 21,3503 31751 DCA FUNCTION
062681,000479: 21,3504 00006 EXTEND
062682,000480: 21,3505 11746 DV HALFARG
062683,000481: # ININDEX AND SHFTFLAG PRESERVE INFO FOR
062684,000482: # RESCALING AFTER ROOT PROCESS.
062685,000483: 21,3506 00006 SCALDONE EXTEND
062686,000484: 21,3507 23751 QXCH FUNCTION +1 # SAVE Q FOR RETURN
062687,000485: 21,3510 00006 EXTEND
062688,000486: 21,3511 74736 MP BIT14
062689,000487: 21,3512 55746 TS HALFARG
062690,000488: 21,3513 74737 MASK BIT13
062691,000489: 21,3514 10000 CCS A
062692,000490: 21,3515 33633 CA OCT11276
062693,000491: 21,3516 63631 AD ROOTHALF # INITIAL GUESS IS ROOT 1/2 OR POSMAX
062694,000492: 21,3517 03635 TC ROOTCYCL
062695,000493: 21,3520 03635 TC ROOTCYCL
062696,000494: 21,3521 03635 TC ROOTCYCL
062697,000495: 21,3522 01751 TC FUNCTION +1
062698,000496:
062699,000497: # ****************************************************************************************************************
062700,000498:
062701,000499: 21,3523 03440 RSTOFGTS TC GTSQRT
062702,000500: 21,3524 57741 PRODUCT XCH K2CNTRAL
062703,000501: 21,3525 00006 EXTEND
062704,000502: 21,3526 71741 MP K2CNTRAL
062705,000503: 21,3527 53742 DXCH K2CNTRAL
062706,000504: 21,3530 00006 EXTEND # THE PRODUCT OF
062707,000505: 21,3531 70001 MP L # 1/2 2 1/2
062708,000506: 21,3532 27742 ADS K2CNTRAL +1 # K *(DEL*OMEGA + ALPHA /(2*K))
062709,000507: 21,3533 54001 TS L # AND
062710,000508: 21,3534 13536 TCF +2 # 2
062711,000509: 21,3535 27741 ADS K2CNTRAL # DEL*(DEL*OMEGA + ALPHA /(2*K)) NOW IN
062712,000510: # K2CNTRAL
062713,000511:
062714,000512: 21,3536 31743 DOSHIFT CA ININDEX
062715,000513: 21,3537 00006 EXTEND # MULTIPLY IN THE FACTOR 2(-S), RETURNED
062716,000514: 21,3540 74736 MP BIT14 # BY THE GTSQRT SUBROUTINE
062717,000515: 21,3541 27740 ADS SHFTFLAG
062718,000516: 21,3542 00006 EXTEND
062719,000517: 21,3543 13562 BZF ADDITIN
062720,000518: 21,3544 51740 INDEX SHFTFLAG
062721,000519: 21,3545 34735 CA BIT15
![]() |
Page 1475 |
062723,000521: 21,3546 57741 XCH K2CNTRAL
062724,000522: 21,3547 00006 EXTEND
062725,000523: 21,3550 71741 MP K2CNTRAL
062726,000524: 21,3551 21737 DAS K2THETA
062727,000525: 21,3552 57741 XCH K2CNTRAL
062728,000526: 21,3553 00006 EXTEND
062729,000527: 21,3554 71742 MP K2CNTRAL +1
062730,000528: 21,3555 27737 ADS K2THETA +1
062731,000529: 21,3556 54001 TS L
062732,000530: 21,3557 13561 TCF +2
062733,000531: 21,3560 27736 ADS K2THETA
062734,000532:
062735,000533: 21,3561 13565 TCF NEGUSUM
062736,000534:
062737,000535: 21,3562 00006 ADDITIN EXTEND
062738,000536: 21,3563 31742 DCA K2CNTRAL
062739,000537: 21,3564 21737 DAS K2THETA # NOW ADD IN THE K2THETA TERM.
062740,000538: 21,3565 11736 NEGUSUM CCS K2THETA # TEST SIGN OF HIGH ORDER PART.
062741,000539: 21,3566 13572 TCF NEGDRIVE
062742,000540: 21,3567 13571 TCF +2
062743,000541: 21,3570 13574 TCF POSDRIVE
062744,000542:
062745,000543: 21,3571 11737 CCS K2THETA +1 # SIGN TEST FOR LOW ORDER PART.
062746,000544: 21,3572 34753 NEGDRIVE CA BIT1
062747,000545: 21,3573 13575 TCF +2 # STOP GIMBAL DRIVE FOR A ZERO NEGUSUM.
062748,000546: 21,3574 44753 POSDRIVE CS BIT1
062749,000547: 21,3575 54001 TS L # SAVE FOR DRIVE REVERSAL TEST.
062750,000548: 21,3576 51747 INDEX QRCNTR
062751,000549: 21,3577 57501 XCH NEGUQ
062752,000550:
062753,000551: 21,3600 00006 EXTEND
062754,000552: 21,3601 70001 MP L # MULTIPLY OLD NEGU AND NEW NEGU.
062755,000553: 21,3602 10001 CCS L
062756,000554: 21,3603 13620 TCF LOUPE # NON-ZERO GIMBAL DRIVE BEING CONTINUED.
062757,000555:
062758,000556: 21,3604 13615 TCF ZEROLOUP # NO REVERSAL PROBLEM HERE.
062759,000557:
062760,000558: 21,3605 13607 TCF REVERSAL # NON-ZERO GIMBAL DRIVE BEING REVERSED.
062761,000559: 21,3606 13615 TCF ZEROLOUP # NO REVERSAL PROBLEM HERE.
062762,000560:
062763,000561: 21,3607 51747 REVERSAL INDEX QRCNTR # A ZERO-DRIVE PAUSE IS NEEDED HERE. ZERO
062764,000562: 21,3610 55510 TS QACCDOT # IS IN A REGISTER FROM CCS ON (-1).
062765,000563: 21,3611 51747 INDEX QRCNTR
062766,000564: 21,3612 43632 CS GMBLBITA
062767,000565: 21,3613 00006 EXTEND
062768,000566: 21,3614 03012 WAND CHAN12
062769,000567:
062770,000568: 21,3615 41262 ZEROLOUP CS RCSFLAGS # SET UP REQUEST FOR ACDT+C12 CALL.
062771,000569: 21,3616 74747 MASK CALLGMBL
062772,000570: 21,3617 27262 ADS RCSFLAGS
![]() |
Page 1476 |
062774,000572: 21,3620 11747 LOUPE CCS QRCNTR # HAVE BOTH AXES BEEN PROCESSED?
062775,000573: 21,3621 13114 TCF GOQTRIMG # NO. DO Q AXIS NEXT.
062776,000574:
062777,000575: 21,3622 31505 CA SAVESR # RESTORE THE SR
062778,000576: 21,3623 54021 TS SR
062779,000577:
062780,000578: 21,3624 00006 GOCLOSE EXTEND # TERMINATE THE JASK.
062781,000579: 21,3625 33630 DCA CLOSEADR
062782,000580: 21,3626 52006 DTCB
062783,000581:
062784,000582: 21,3627 E6,1536 EBANK= AOSQ
062785,000583: 21,3627 03270 36106 CLOSEADR 2CADR CLOSEOUT # TERMINATE THE JASK.
062786,000584:
062787,000585: 21,3631 5741 TWELVE EQUALS OCT14
062788,000586: 21,3631 26501 ROOTHALF OCTAL 26501 # SQUARE ROOT OF 1/2
062789,000587: 21,3632 01400 GMBLBITA OCTAL 01400 # INDEXED WRT GMBLBITB DO NOT MOVE ******
062790,000588: 21,3633 11276 OCT11276 OCTAL 11276 # POSMAX - ROOTHALF
062791,000589: 21,3634 06000 GMBLBITB OCTAL 06000 # INDEXED WRT GMBLBITA DO NOT MOVE ******
062792,000590:
062793,000591: # SUBROUTINE ROOTCYCL: BY CRAIG WORK, 3 APRIL 68
062794,000592:
062795,000593: # ROOTCYCL IS A SUBROUTINE WHICH EXECUTES ONE NEWTON SQUARE ROOT ALGORITHM ITERATION. THE INITIAL GUESS AT THE
062796,000594: # SQUARE ROOT IS PRESUMED TO BE IN THE A REGISTER AND ONE-HALF THE SQUARE IS TAKEN FROM HALFARG. THE NEW APPROXI-
062797,000595: # MATION TO THE SQUARE ROOT IS RETURNED IN THE A REGISTER. DEBRIS: A, L, SR, SCRATCH. ROOTCYCL IS CALLED FROM
062798,000596: # LOCATION (LOC) BY A TC ROOTCYCL, AND RETURNS (TC Q) TO LOC +1.
062799,000597:
062800,000598: # WARNING: IF THE INITIAL GUESS IS NOT GREATER THAN THE SQUARE, DIVIDE OR ADD OVERFLOW IS A REAL POSSIBILITY.
062801,000599:
062802,000600: 21,3635 55745 ROOTCYCL TS SCRATCH # STORE X
062803,000601: 21,3636 54021 TS SR # X/2 NOW IN SR
062804,000602: 21,3637 31746 CA HALFARG # ARG/2 IN THE A REG
062805,000603: 21,3640 22007 ZL # PREPARE FOR DIVISION
062806,000604: 21,3641 00006 EXTEND
062807,000605: 21,3642 11745 DV SCRATCH # (ARG/X)/2
062808,000606: 21,3643 60021 AD SR # (X + ARG/X)/2 IN THE A REG
062809,000607: 21,3644 00002 TC Q
062810,000608:
062811,000609:
End of include-file TRIM_GIMBAL_CONTROL_SYSTEM.agc. Parent file is MAIN.agc