Source Code
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These source-code files are part of a reconstructed copy of Luminary 173, the
second (unflown) release of the Apollo 14 Lunar Module (LM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with reconstructed source code for Luminary 178. Changes
between revision 173 and 178 were backed out, as described by Luminary memo 167
(revision 1). 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 173 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.
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059313,000002: ## Copyright: Public domain.
059314,000003: ## Filename: RTB_OP_CODES.agc
059315,000004: ## Purpose: A section of Luminary revision 173.
059316,000005: ## It is part of the reconstructed source code for the second
059317,000006: ## (unflown) release of the flight software for the Lunar
059318,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 14.
059319,000008: ## The code has been recreated from a reconstructed copy of
059320,000009: ## Luminary 178, as well as Luminary memo 167 (revision 1).
059321,000010: ## It has been adapted such that the resulting bugger words
059322,000011: ## exactly match those specified for Luminary 173 in NASA
059323,000012: ## drawing 2021152N, which gives relatively high confidence
059324,000013: ## that the reconstruction is correct.
059325,000014: ## Reference: pp. 1385-1390
059326,000015: ## Assembler: yaYUL
059327,000016: ## Contact: Ron Burkey <info@sandroid.org>.
059328,000017: ## Website: www.ibiblio.org/apollo/index.html
059329,000018: ## Mod history: 2019-09-18 MAS Created from Luminary 178.
059330,000019:
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Page 1385
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059332,000021: 22,3772 BANK 22
059333,000022: 10,2000 SETLOC RTBCODES
059334,000023: 10,2000 BANK
059335,000024:
059336,000025: 10,3574 E5,1664 EBANK= XNB
059337,000026: 10,3574 COUNT* $$/RTB
059338,000027:
059339,000028: # LOAD TIME2, TIME1 INTO MPAC:
059340,000029:
059341,000030: 10,3574 00006 LOADTIME EXTEND
059342,000031: 10,3575 30025 DCA TIME2
059343,000032: 10,3576 16060 TCF SLOAD2
059344,000033:
059345,000034: # CONVERT THE SINGLE PRECISION 2'S COMPLEMENT NUMBER ARRIVING IN MPAC (SCALED IN HALF-REVOLUTIONS) TO A
059346,000035: # DP 1'S COMPLEMENT NUMBER SCALED IN REVOLUTIONS.
059347,000036:
059348,000037: 10,3577 10154 CDULOGIC CCS MPAC
059349,000038: 10,3600 34755 CAF ZERO
059350,000039: 10,3601 13604 TCF +3
059351,000040: 10,3602 13603 NOOP
059352,000041: 10,3603 44736 CS HALF
059353,000042:
059354,000043: 10,3604 54155 TS MPAC +1
059355,000044: 10,3605 34755 CAF ZERO
059356,000045: 10,3606 56154 XCH MPAC
059357,000046: 10,3607 00006 EXTEND
059358,000047: 10,3610 74736 MP HALF
059359,000048: 10,3611 20155 DAS MPAC
059360,000049: 10,3612 16064 TCF DANZIG # MODE IS ALREADY AT DOUBLE-PRECISION
059361,000050:
059362,000051: # FORCE TP SIGN AGREEMENT IN MPAC:
059363,000052:
059364,000053: 10,3613 07262 SGNAGREE TC TPAGREE
059365,000054: 10,3614 16064 TCF DANZIG
059366,000055:
059367,000056: # CONVERT THE DP 1'S COMPLEMENT ANGLE SCALED IN REVOLUTIONS TO A SINGLE PRECISION 2'S COMPLEMENT ANGLE
059368,000057: # SCALED IN HALF-REVOLUTIONS.
059369,000058:
059370,000059: 10,3615 03645 1STO2S TC 1TO2SUB
059371,000060: 10,3616 34755 CAF ZERO
059372,000061: 10,3617 54155 TS MPAC +1
059373,000062: 10,3620 16063 TCF NEWMODE
059374,000063:
059375,000064: # DO 1STO2S ON A VECTOR OF ANGLES:
059376,000065:
059377,000066: 10,3621 03645 V1STO2S TC 1TO2SUB # ANSWER ARRIVES IN A AND MPAC.
059378,000067:
059379,000068: 10,3622 52162 DXCH MPAC +5
059380,000069: 10,3623 52155 DXCH MPAC
059381,000070: 10,3624 03645 TC 1TO2SUB
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Page 1386
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059383,000072: 10,3625 54156 TS MPAC +2
059384,000073:
059385,000074: 10,3626 52160 DXCH MPAC +3
059386,000075: 10,3627 52155 DXCH MPAC
059387,000076: 10,3630 03645 TC 1TO2SUB
059388,000077: 10,3631 54155 TS MPAC +1
059389,000078:
059390,000079: 10,3632 30161 CA MPAC +5
059391,000080: 10,3633 54154 TS MPAC
059392,000081:
059393,000082: 10,3634 34753 TPMODE CAF ONE # MODE IS TP.
059394,000083: 10,3635 16063 TCF NEWMODE
059395,000084:
059396,000085: # V1STO2S FOR 2 COMPONENT VECTOR. USED BY RR.
059397,000086:
059398,000087: 10,3636 03645 2V1STO2S TC 1TO2SUB
059399,000088: 10,3637 52160 DXCH MPAC +3
059400,000089: 10,3640 52155 DXCH MPAC
059401,000090: 10,3641 03645 TC 1TO2SUB
059402,000091: 10,3642 54001 TS L
059403,000092: 10,3643 30157 CA MPAC +3
059404,000093: 10,3644 16060 TCF SLOAD2
059405,000094:
059406,000095: # SUBROUTINE TO DO DOUBLING AND 1'S TO 2'S CONVERSION:
059407,000096:
059408,000097: 10,3645 52155 1TO2SUB DXCH MPAC # FINAL MPAC +1 UNSPECIFIED.
059409,000098: 10,3646 20001 DDOUBL
059410,000099: 10,3647 10000 CCS A
059411,000100: 10,3650 64753 AD ONE
059412,000101: 10,3651 13653 TCF +2
059413,000102: 10,3652 40000 COM # THIS WAS REVERSE OF MSU.
059414,000103:
059415,000104: 10,3653 54154 TS MPAC # AND SKIP ON OVERFLOW.
059416,000105: 10,3654 00002 TC Q
059417,000106:
059418,000107: 10,3655 50000 INDEX A # OVERFLOW UNCORRECT AND IN MSU.
059419,000108: 10,3656 34734 CAF LIMITS
059420,000109: 10,3657 26154 ADS MPAC
059421,000110: 10,3660 00002 TC Q
059422,000111:
059423,000112: # THE FOLLOWING ROUTINE INCREMENTS IN 2S COMPLEMENT THE REGISTER WHOSE ADDRESS IS IN BUF BY THE 1S COMPL.
059424,000113: # QUANTITY FOUND IN TEM2. THIS MAY BE USED TO INCREMENT DESIRED IMU AND OPTICS CDU ANGLES OR ANY OTHER 2S COMPL.
059425,000114: # (+0 UNEQUAL TO -0) QUANTITY. MAY BE CALLED BY BANKCALL/SWCALL.
059426,000115:
059427,000116: 10,3661 54142 CDUINC TS TEM2 # 1S COMPL.QUANT. ARRIVES IN ACC. STORE IT
059428,000117: 10,3662 50130 INDEX BUF
059429,000118: 10,3663 10000 CCS 0 # CHANGE 2S COMPL. ANGLE(IN BUF)INTO 1S
059430,000119: 10,3664 64753 AD ONE
059431,000120: 10,3665 13671 TCF +4
059432,000121: 10,3666 64753 AD ONE
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Page 1387
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059434,000123: 10,3667 64753 AD ONE # OVERFLOW HERE IF 2S COMPL. IS 180 DEG.
059435,000124: 10,3670 40000 COM
059436,000125:
059437,000126: 10,3671 60142 AD TEM2 # SULT MOVES FROM 2ND TO 3D QUAD.(OR BACK)
059438,000127: 10,3672 10000 CCS A # BACK TO 2S COMPL.
059439,000128: 10,3673 64753 AD ONE
059440,000129: 10,3674 13676 TCF +2
059441,000130: 10,3675 40000 COM
059442,000131: 10,3676 54142 TS TEM2 # STORE 14BIT QUANTITY WITH PRESENT SIGN
059443,000132: 10,3677 13703 TCF +4
059444,000133: 10,3700 50000 INDEX A # SIGN.
059445,000134: 10,3701 34734 CAF LIMITS # FIX IT,BY ADDING IN 37777 OR 40000
059446,000135: 10,3702 60142 AD TEM2
059447,000136:
059448,000137: 10,3703 50130 INDEX BUF
059449,000138: 10,3704 54000 TS 0 # STORE NEW ANGLE IN 2S COMPLEMENT.
059450,000139: 10,3705 00002 TC Q
059451,000140:
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Page 1388
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059453,000142: # RTB TO TORQUE GYROS, EXCEPT FOR THE CALL TO IMUSTALL. ECADR OF COMMANDS ARRIVES IN X1.
059454,000143:
059455,000144: 10,3706 50120 PULSEIMU INDEX FIXLOC # ADDRESS OF GYRO COMMANDS SHOULD BE IN X1
059456,000145: 10,3707 30046 CA X1
059457,000146: 10,3710 04616 TC BANKCALL
059458,000147: 10,3711 17307 CADR IMUPULSE
059459,000148: 10,3712 16064 TCF DANZIG
059460,000149:
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Page 1389
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059462,000151: # THE SUBROUTINE SIGNMPAC SETS C(MPAC, MPAC +1) TO SIGN(MPAC).
059463,000152: # FOR THIS, ONLY THE CONTENTS OF MPAC ARE EXAMINED. ALSO +0 YIELDS POSMAX AND -0 YIELDS NEGMAX.
059464,000153:
059465,000154: # ENTRY MAY BE BY EITHER OF THE FOLLOWING:
059466,000155:
059467,000156: # 1. LIMIT THE SIZE OF MPAC ON INTERPRETIVE OVERFLOW:
059468,000157: # ENTRY: BOVB
059469,000158: # SIGNMPAC
059470,000159:
059471,000160: # 2. GENERATE IN MPAC THE SIGNUM FUNCTION OF MPAC:
059472,000161: # ENTRY: RTB
059473,000162: # SIGNMPAC
059474,000163:
059475,000164: # IN EITHER CASE, RETURN IS TO THE NEXT INTERPRETIVE INSTRUCTION IN THE CALLING SEQUENCE.
059476,000165:
059477,000166: 10,3713 00006 SIGNMPAC EXTEND
059478,000167: 10,3714 34733 DCA DPOSMAX
059479,000168: 10,3715 52155 DXCH MPAC
059480,000169: 10,3716 10000 CCS A
059481,000170: 10,3717 34755 DPMODE CAF ZERO # SETS MPAC +2 TO ZERO IN THE PROCESS
059482,000171: 10,3720 16062 TCF SLOAD2 +2
059483,000172: 10,3721 13722 TCF +1
059484,000173: 10,3722 00006 EXTEND
059485,000174: 10,3723 44733 DCS DPOSMAX
059486,000175: 10,3724 16060 TCF SLOAD2
059487,000176:
059488,000177: # RTB OP CODE NORMUNIT IS LIKE INTERPRETIVE INSTRUCTION UNIT, EXCEPT THAT IT CAN BE DEPENDED ON NOT TO BLOW
059489,000178: # UP WHEN THE VECTOR BEING UNITIZED IS VERY SMALL -- IT WILL BLOW UP WHEN ALL COMPONENTS ARE ZERO. IF NORMUNIT
059490,000179: # IS USED AND THE UPPER ORDER HALVES OF ALL COMPONENTS ARE ZERO, THE MAGNITUDE RETURNED IN 36D WILL BE TOO LARGE
059491,000180: # BY A FACTOR OF 2(13) AND THE SQUARED MAGNITUDE RETURNED AT 34D WILL BE TOO BIG BY A FACTOR OF 2(26).
059492,000181:
059493,000182: 10,3725 34753 NORMUNX1 CAF ONE
059494,000183: 10,3726 13730 TCF NORMUNIT +1
059495,000184: 10,3727 34755 NORMUNIT CAF ZERO
059496,000185: 10,3730 60120 AD FIXLOC
059497,000186: 10,3731 54156 TS MPAC +2
059498,000187: 10,3732 04616 TC BANKCALL # GET SIGN AGREEMENT IN ALL COMPONENTS
059499,000188: 10,3733 01010 CADR VECAGREE
059500,000189: 10,3734 10154 CCS MPAC
059501,000190: 10,3735 13771 TCF NOSHIFT
059502,000191: 10,3736 13740 TCF +2
059503,000192: 10,3737 13771 TCF NOSHIFT
059504,000193: 10,3740 10157 CCS MPAC +3
059505,000194: 10,3741 13771 TCF NOSHIFT
059506,000195: 10,3742 13744 TCF +2
059507,000196: 10,3743 13771 TCF NOSHIFT
059508,000197: 10,3744 10161 CCS MPAC +5
059509,000198: 10,3745 13771 TCF NOSHIFT
059510,000199: 10,3746 13750 TCF +2
059511,000200: 10,3747 13771 TCF NOSHIFT
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Page 1390
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059513,000202: 10,3750 30155 CA MPAC +1 # SHIFT ALL COMPONENTS LEFT 13
059514,000203: 10,3751 00006 EXTEND
059515,000204: 10,3752 74736 MP BIT14
059516,000205: 10,3753 20155 DAS MPAC # DAS GAINS A LITTLE ACCURACY
059517,000206: 10,3754 30160 CA MPAC +4
059518,000207: 10,3755 00006 EXTEND
059519,000208: 10,3756 74736 MP BIT14
059520,000209: 10,3757 20160 DAS MPAC +3
059521,000210: 10,3760 30162 CA MPAC +6
059522,000211: 10,3761 00006 EXTEND
059523,000212: 10,3762 74736 MP BIT14
059524,000213: 10,3763 20162 DAS MPAC +5
059525,000214: 10,3764 34761 CAF THIRTEEN
059526,000215: 10,3765 50156 INDEX MPAC +2
059527,000216: 10,3766 54045 TS 37D
059528,000217: 10,3767 04635 OFFTUNIT TC POSTJUMP
059529,000218: 10,3770 01024 CADR UNIT +1 # SKIP THE "TC VECAGREE" DONE AT UNIT
059530,000219:
059531,000220:
059532,000221: 10,3771 34755 NOSHIFT CAF ZERO
059533,000222: 10,3772 13765 TCF OFFTUNIT -2
059534,000223:
059535,000224:
059536,000225: # RTB VECSGNAG ...FORCES SIGN AGREEMENT OF VECTOR IN MPAC.
059537,000226:
059538,000227: 10,3773 04616 VECSGNAG TC BANKCALL
059539,000228: 10,3774 01010 CADR VECAGREE
059540,000229: 10,3775 06064 TC DANZIG
End of include-file RTB_OP_CODES.agc. Parent file is MAIN.agc