Source Code
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These source-code files are part of a reconstructed copy of Luminary 69/2,
the flown, final release of the Apollo 10 Lunar Module (LM) Apollo Guidance Computer (AGC) software.
The reconstruction is based on the source code of Luminary 69 — i.e., the
initial, unflown version, "revision 0" — of which
a contemporary listing was available. The code was then updated by incorporating the
differences between Luminary 69 and Luminary 69/2, known from other contemporary
documentation. The only such difference is the implementation in
Luminary 69/2 of the "R-2 Lunar Potential Model", the source code for which was taken
from program Luminary 99/1 (Apollo 11 LM), of which a contemporary listing was also available.
Finally, the now-reconstructed Luminary 69/2 was then validated by assembling it to
executable form and verifying that its memory banks had the correct checksums,
known from still other contemporary documentation.
Note that page numbers in the reconstructed code match those in the original Luminary 69
program listing, or in the ORBITAL INTEGRATION log section, in Luminary 99/1. Page numbers
would certainly differ somewhat in a contemporary Luminary 69/2 listing.
Moreover, annotations that were not present in the contemporary source code have been added
to the reconstructed code to justify each change in Luminary 69/2 relative to
Luminary 69. Here's a guide to the Apollo documentation referenced in those annotations:
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.
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060066,000002: ## Copyright: Public domain.
060067,000003: ## Filename: RTB_OP_CODES.agc
060068,000004: ## Purpose: A section of LUM69 revision 2.
060069,000005: ## It is part of the reconstructed source code for the flown
060070,000006: ## version of the flight software for the Lunar Module's (LM)
060071,000007: ## Apollo Guidance Computer (AGC) for Apollo 10. The code has
060072,000008: ## been recreated from a copy of Luminary revsion 069, using
060073,000009: ## changes present in Luminary 099 which were described in
060074,000010: ## Luminary memos 75 and 78. The code has been adapted such
060075,000011: ## that the resulting bugger words exactly match those specified
060076,000012: ## for LUM69 revision 2 in NASA drawing 2021152B, which gives
060077,000013: ## relatively high confidence that the reconstruction is correct.
060078,000014: ## Reference: pp. 1390-1397
060079,000015: ## Assembler: yaYUL
060080,000016: ## Contact: Ron Burkey <info@sandroid.org>.
060081,000017: ## Website: www.ibiblio.org/apollo/index.html
060082,000018: ## Mod history: 2019-07-27 MAS Created from Luminary 69.
060083,000019:
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Page 1390
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060085,000021: 22,3731 BANK 22
060086,000022: 10,2000 SETLOC RTBCODES
060087,000023: 10,2000 BANK
060088,000024:
060089,000025: 10,3462 E5,1664 EBANK= XNB
060090,000026: 10,3462 COUNT* $$/RTB
060091,000027:
060092,000028: # LOAD TIME2, TIME1 INTO MPAC:
060093,000029:
060094,000030: 10,3462 00006 LOADTIME EXTEND
060095,000031: 10,3463 30025 DCA TIME2
060096,000032: 10,3464 16054 TCF SLOAD2
060097,000033:
060098,000034: # CONVERT THE SINGLE PRECISION 2'S COMPLEMENT NUMBER ARRIVING IN MPAC (SCALED IN HALF-REVOLUTIONS) TO A
060099,000035: # DP 1'S COMPLEMENT NUMBER SCALED IN REVOLUTIONS.
060100,000036:
060101,000037: 10,3465 10154 CDULOGIC CCS MPAC
060102,000038: 10,3466 34755 CAF ZERO
060103,000039: 10,3467 13472 TCF +3
060104,000040: 10,3470 13471 NOOP
060105,000041: 10,3471 44736 CS HALF
060106,000042:
060107,000043: 10,3472 54155 TS MPAC +1
060108,000044: 10,3473 34755 CAF ZERO
060109,000045: 10,3474 56154 XCH MPAC
060110,000046: 10,3475 00006 EXTEND
060111,000047: 10,3476 74736 MP HALF
060112,000048: 10,3477 20155 DAS MPAC
060113,000049: 10,3500 16060 TCF DANZIG # MODE IS ALREADY AT DOUBLE-PRECISION
060114,000050:
060115,000051: # READ THE PIPS INTO MPAC WITHOUT CHANGING THEM:
060116,000052:
060117,000053: 10,3501 00004 READPIPS INHINT
060118,000054: 10,3502 30037 CA PIPAX
060119,000055: 10,3503 54154 TS MPAC
060120,000056: 10,3504 30040 CA PIPAY
060121,000057: 10,3505 54157 TS MPAC +3
060122,000058: 10,3506 30041 CA PIPAZ
060123,000059: 10,3507 00003 RELINT
060124,000060: 10,3510 54161 TS MPAC +5
060125,000061:
060126,000062: 10,3511 34755 CAF ZERO
060127,000063: 10,3512 54155 TS MPAC +1
060128,000064: 10,3513 54160 TS MPAC +4
060129,000065: 10,3514 54162 TS MPAC +6
060130,000066:
060131,000067: 10,3515 16520 VECMODE TCF VMODE
060132,000068:
060133,000069: # FORCE TP SIGN AGREEMENT IN MPAC:
060134,000070:
060135,000071: 10,3516 07256 SGNAGREE TC TPAGREE
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Page 1391
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060137,000073: 10,3517 16060 TCF DANZIG
060138,000074:
060139,000075: # CONVERT THE DP 1'S COMPLEMENT ANGLE SCALED IN REVOLUTIONS TO A SINGLE PRECISION 2'S COMPLEMENT ANGLE
060140,000076: # SCALED IN HALF-REVOLUTIONS.
060141,000077:
060142,000078: 10,3520 03550 1STO2S TC 1TO2SUB
060143,000079: 10,3521 34755 CAF ZERO
060144,000080: 10,3522 54155 TS MPAC +1
060145,000081: 10,3523 16057 TCF NEWMODE
060146,000082:
060147,000083: # DO 1STO2S ON A VECTOR OF ANGLES:
060148,000084:
060149,000085: 10,3524 03550 V1STO2S TC 1TO2SUB # ANSWER ARRIVES IN A AND MPAC.
060150,000086:
060151,000087: 10,3525 52162 DXCH MPAC +5
060152,000088: 10,3526 52155 DXCH MPAC
060153,000089: 10,3527 03550 TC 1TO2SUB
060154,000090: 10,3530 54156 TS MPAC +2
060155,000091:
060156,000092: 10,3531 52160 DXCH MPAC +3
060157,000093: 10,3532 52155 DXCH MPAC
060158,000094: 10,3533 03550 TC 1TO2SUB
060159,000095: 10,3534 54155 TS MPAC +1
060160,000096:
060161,000097: 10,3535 30161 CA MPAC +5
060162,000098: 10,3536 54154 TS MPAC
060163,000099:
060164,000100: 10,3537 34753 TPMODE CAF ONE # MODE IS TP.
060165,000101: 10,3540 16057 TCF NEWMODE
060166,000102:
060167,000103: # V1STO2S FOR 2 COMPONENT VECTOR. USED BY RR.
060168,000104:
060169,000105: 10,3541 03550 2V1STO2S TC 1TO2SUB
060170,000106: 10,3542 52160 DXCH MPAC +3
060171,000107: 10,3543 52155 DXCH MPAC
060172,000108: 10,3544 03550 TC 1TO2SUB
060173,000109: 10,3545 54001 TS L
060174,000110: 10,3546 30157 CA MPAC +3
060175,000111: 10,3547 16054 TCF SLOAD2
060176,000112:
060177,000113: # SUBROUTINE TO DO DOUBLING AND 1'S TO 2'S CONVERSION:
060178,000114:
060179,000115: 10,3550 52155 1TO2SUB DXCH MPAC # FINAL MPAC +1 UNSPECIFIED.
060180,000116: 10,3551 20001 DDOUBL
060181,000117: 10,3552 10000 CCS A
060182,000118: 10,3553 64753 AD ONE
060183,000119: 10,3554 13556 TCF +2
060184,000120: 10,3555 40000 COM # THIS WAS REVERSE OF MSU.
060185,000121:
060186,000122: 10,3556 54154 TS MPAC # AND SKIP ON OVERFLOW.
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Page 1392
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060188,000124: 10,3557 00002 TC Q
060189,000125:
060190,000126: 10,3560 50000 INDEX A # OVERFLOW UNCORRECT AND IN MSU.
060191,000127: 10,3561 34734 CAF LIMITS
060192,000128: 10,3562 26154 ADS MPAC
060193,000129: 10,3563 00002 TC Q
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Page 1393
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060195,000131: # SUBROUTINE TO INCREMENT CDUS
060196,000132: 10,3564 33577 INCRCDUS CAF LOCTHETA
060197,000133: 10,3565 54130 TS BUF # PLACE ADRES(THETA) IN BUF.
060198,000134: 10,3566 30154 CAE MPAC # INCREMENT IN 1S COMPL.
060199,000135: 10,3567 03600 TC CDUINC
060200,000136:
060201,000137: 10,3570 24130 INCR BUF
060202,000138: 10,3571 30157 CAE MPAC +3
060203,000139: 10,3572 03600 TC CDUINC
060204,000140:
060205,000141: 10,3573 24130 INCR BUF
060206,000142: 10,3574 30161 CAE MPAC +5
060207,000143: 10,3575 03600 TC CDUINC
060208,000144:
060209,000145: 10,3576 13515 TCF VECMODE
060210,000146:
060211,000147: 10,3577 00321 LOCTHETA ADRES THETAD
060212,000148:
060213,000149: # THE FOLLOWING ROUTINE INCREMENTS IN 2S COMPLEMENT THE REGISTER WHOSE ADDRESS IS IN BUF BY THE 1S COMPL.
060214,000150: # QUANTITY FOUND IN TEM2. THIS MAY BE USED TO INCREMENT DESIRED IMU AND OPTICS CDU ANGLES OR ANY OTHER 2S COMPL.
060215,000151: # (+0 UNEQUAL TO -0) QUANTITY. MAY BE CALLED BY BANKCALL/SWCALL.
060216,000152:
060217,000153: 10,3600 54142 CDUINC TS TEM2 # 1S COMPL.QUANT. ARRIVES IN ACC. STORE IT
060218,000154: 10,3601 50130 INDEX BUF
060219,000155: 10,3602 10000 CCS 0 # CHANGE 2S COMPL. ANGLE(IN BUF)INTO 1S
060220,000156: 10,3603 64753 AD ONE
060221,000157: 10,3604 13610 TCF +4
060222,000158: 10,3605 64753 AD ONE
060223,000159: 10,3606 64753 AD ONE # OVERFLOW HERE IF 2S COMPL. IS 180 DEG.
060224,000160: 10,3607 40000 COM
060225,000161:
060226,000162: 10,3610 60142 AD TEM2 # SULT MOVES FROM 2ND TO 3D QUAD.(OR BACK)
060227,000163: 10,3611 10000 CCS A # BACK TO 2S COMPL.
060228,000164: 10,3612 64753 AD ONE
060229,000165: 10,3613 13615 TCF +2
060230,000166: 10,3614 40000 COM
060231,000167: 10,3615 54142 TS TEM2 # STORE 14BIT QUANTITY WITH PRESENT SIGN
060232,000168: 10,3616 13622 TCF +4
060233,000169: 10,3617 50000 INDEX A # SIGN.
060234,000170: 10,3620 34734 CAF LIMITS # FIX IT, BY ADDING IN 37777 OR 40000
060235,000171: 10,3621 60142 AD TEM2
060236,000172:
060237,000173: 10,3622 50130 INDEX BUF
060238,000174: 10,3623 54000 TS 0 # STORE NEW ANGLE IN 2S COMPLEMENT.
060239,000175: 10,3624 00002 TC Q
060240,000176:
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Page 1394
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060242,000178: # RTB TO TORQUE GYROS, EXCEPT FOR THE CALL TO IMUSTALL. ECADR OF COMMANDS ARRIVES IN X1.
060243,000179:
060244,000180: 10,3625 50120 PULSEIMU INDEX FIXLOC # ADDRESS OF GYRO COMMANDS SHOULD BE IN X1
060245,000181: 10,3626 30046 CA X1
060246,000182: 10,3627 04616 TC BANKCALL
060247,000183: 10,3630 17276 CADR IMUPULSE
060248,000184: 10,3631 16060 TCF DANZIG
060249,000185:
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Page 1395
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060251,000187: # EACH ROUTINE TAKES A 3X3 MATRIX STORED IN DOUBLE PRECISION IN A FIXED AREA OF ERASABLE MEMORY AND REPLACES IT
060252,000188: # WITH THE TRANSPOSE MATRIX. TRANSP1 USES LOCATIONS XNB+0,+1 THROUGH XNB+16D, 17D AND TRANSP2 USES LOCATIONS
060253,000189: # XNB1+0,+1 THROUGH XNB1+16D, 17D. EACH MATRIX IS STORED BY ROWS.
060254,000190:
060255,000191: 10,3632 02664 XNBEB ECADR XNB
060256,000192: 10,3633 03467 XNB1EB ECADR XNB1
060257,000193:
060258,000194: 10,3634 E5,1664 EBANK= XNB
060259,000195:
060260,000196: 10,3634 33632 TRANSP1 CAF XNBEB
060261,000197: 10,3635 54003 TS EBANK
060262,000198: 10,3636 53667 DXCH XNB +2
060263,000199: 10,3637 53673 DXCH XNB +6
060264,000200: 10,3640 53667 DXCH XNB +2
060265,000201:
060266,000202: 10,3641 53671 DXCH XNB +4
060267,000203: 10,3642 53701 DXCH XNB +12D
060268,000204: 10,3643 53671 DXCH XNB +4
060269,000205:
060270,000206: 10,3644 53677 DXCH XNB +10D
060271,000207: 10,3645 53703 DXCH XNB +14D
060272,000208: 10,3646 53677 DXCH XNB +10D
060273,000209: 10,3647 16060 TCF DANZIG
060274,000210:
060275,000211: 10,3650 E7,1467 EBANK= XNB1
060276,000212:
060277,000213: 10,3650 33633 TRANSP2 CAF XNB1EB
060278,000214: 10,3651 54003 TS EBANK
060279,000215: 10,3652 53472 DXCH XNB1 +2
060280,000216: 10,3653 53476 DXCH XNB1 +6
060281,000217: 10,3654 53472 DXCH XNB1 +2
060282,000218:
060283,000219: 10,3655 53474 DXCH XNB1 +4
060284,000220: 10,3656 53504 DXCH XNB1 +12D
060285,000221: 10,3657 53474 DXCH XNB1 +4
060286,000222:
060287,000223: 10,3660 53502 DXCH XNB1 +10D
060288,000224: 10,3661 53506 DXCH XNB1 +14D
060289,000225: 10,3662 53502 DXCH XNB1 +10D
060290,000226: 10,3663 16060 TCF DANZIG
060291,000227:
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Page 1396
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060293,000229: # THE SUBROUTINE SIGNMPAC SETS C(MPAC, MPAC +1) TO SIGN(MPAC).
060294,000230: # FOR THIS, ONLY THE CONTENTS OF MPAC ARE EXAMINED. ALSO +0 YIELDS POSMAX AND -0 YIELDS NEGMAX.
060295,000231:
060296,000232: # ENTRY MAY BE BY EITHER OF THE FOLLOWING:
060297,000233: # 1. LIMIT THE SIZE OF MPAC ON INTERPRETIVE OVERFLOW:
060298,000234: # ENTRY: BOVB
060299,000235: # SIGNMPAC
060300,000236: # 2. GENERATE IN MPAC THE SIGNUM FUNCTION OF MPAC:
060301,000237: # ENTRY: RTB
060302,000238: # SIGNMPAC
060303,000239: # IN EITHER CASE, RETURN IS TO THE NEXT INTERPRETIVE INSTRUCTION IN THE CALLING SEQUENCE.
060304,000240:
060305,000241: 10,3664 00006 SIGNMPAC EXTEND
060306,000242: 10,3665 34733 DCA DPOSMAX
060307,000243: 10,3666 52155 DXCH MPAC
060308,000244: 10,3667 10000 CCS A
060309,000245: 10,3670 34755 DPMODE CAF ZERO # SETS MPAC +2 TO ZERO IN THE PROCESS
060310,000246: 10,3671 16056 TCF SLOAD2 +2
060311,000247: 10,3672 13673 TCF +1
060312,000248: 10,3673 00006 EXTEND
060313,000249: 10,3674 44733 DCS DPOSMAX
060314,000250: 10,3675 16054 TCF SLOAD2
060315,000251:
060316,000252: # RTB OP CODE NORMUNIT IS LIKE INTERPRETIVE INSTRUCTION UNIT, EXCEPT THAT IT CAN BE DEPENDED ON NOT TO BLOW
060317,000253: # UP WHEN THE VECTOR BEING UNITIZED IS VERY SMALL -- IT WILL BLOW UP WHEN ALL COMPONENTS ARE ZERO. IF NORMUNIT
060318,000254: # IS USED AND THE UPPER ORDER HALVES OF ALL COMPONENTS ARE ZERO, THE MAGNITUDE RETURNED IN 36D WILL BE TOO LARGE
060319,000255: # BY A FACTOR OF 2(13) AND THE SQUARED MAGNITUDE RETURNED AT 34D WILL BE TOO BIG BY A FACTOR OF 2(26).
060320,000256:
060321,000257: 10,3676 34753 NORMUNX1 CAF ONE
060322,000258: 10,3677 13701 TCF NORMUNIT +1
060323,000259: 10,3700 34755 NORMUNIT CAF ZERO
060324,000260: 10,3701 60120 AD FIXLOC
060325,000261: 10,3702 54156 TS MPAC +2
060326,000262: 10,3703 04616 TC BANKCALL # GET SIGN AGREEMENT IN ALL COMPONENTS
060327,000263: 10,3704 01010 CADR VECAGREE
060328,000264: 10,3705 10154 CCS MPAC
060329,000265: 10,3706 13742 TCF NOSHIFT
060330,000266: 10,3707 13711 TCF +2
060331,000267: 10,3710 13742 TCF NOSHIFT
060332,000268: 10,3711 10157 CCS MPAC +3
060333,000269: 10,3712 13742 TCF NOSHIFT
060334,000270: 10,3713 13715 TCF +2
060335,000271: 10,3714 13742 TCF NOSHIFT
060336,000272: 10,3715 10161 CCS MPAC +5
060337,000273: 10,3716 13742 TCF NOSHIFT
060338,000274: 10,3717 13721 TCF +2
060339,000275: 10,3720 13742 TCF NOSHIFT
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Page 1397
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060341,000277: 10,3721 30155 CA MPAC +1 # SHIFT ALL COMPONENTS LEFT 13
060342,000278: 10,3722 00006 EXTEND
060343,000279: 10,3723 74736 MP BIT14
060344,000280: 10,3724 20155 DAS MPAC # DAS GAINS A LITTLE ACCURACY
060345,000281: 10,3725 30160 CA MPAC +4
060346,000282: 10,3726 00006 EXTEND
060347,000283: 10,3727 74736 MP BIT14
060348,000284: 10,3730 20160 DAS MPAC +3
060349,000285: 10,3731 30162 CA MPAC +6
060350,000286: 10,3732 00006 EXTEND
060351,000287: 10,3733 74736 MP BIT14
060352,000288: 10,3734 20162 DAS MPAC +5
060353,000289: 10,3735 34761 CAF THIRTEEN
060354,000290: 10,3736 50156 INDEX MPAC +2
060355,000291: 10,3737 54045 TS 37D
060356,000292: 10,3740 04635 OFFTUNIT TC POSTJUMP
060357,000293: 10,3741 01024 CADR UNIT +1 # SKIP THE "TC VECAGREE" DONE AT UNIT
060358,000294:
060359,000295: 10,3742 34755 NOSHIFT CAF ZERO
060360,000296: 10,3743 13736 TCF OFFTUNIT -2
060361,000297:
060362,000298: # RTB VECSGNAG ... FORCES SIGN AGREEMENT OF VECTOR IN MPAC.
060363,000299:
060364,000300: 10,3744 04616 VECSGNAG TC BANKCALL
060365,000301: 10,3745 01010 CADR VECAGREE
060366,000302: 10,3746 06060 TC DANZIG
End of include-file RTB_OP_CODES.agc. Parent file is MAIN.agc