Source Code
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These source-code files are part of a reconstructed copy of Luminary 97, the
second release of the Apollo 11 Lunar Module (LM) Apollo Guidance Computer
(AGC) software. It was created to fix two incorrect ephemeris constants in
Luminary 96, as described by anomaly report LNY-59.
The reconstruction began with source code of Luminary 99 revision 1 previously
transcribed from a digitized copy of that program. The code was then updated
by undoing changes described in original Luminary memos 83 and 85, using asterisks
indicating changed lines in the listing as a guide. The reconstruction was
verified by matching memory-bank checksums to those listed in drawing 2021152D.
Note that page numbers in the reconstructed code match those on the Luminary 099
revision 001 printout, although the added code would likely have changed page
numbers for a real Luminary 97 listing.
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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058978,000002: ## Copyright: Public domain.
058979,000003: ## Filename: RTB_OP_CODES.agc
058980,000004: ## Purpose: A section of Luminary revision 97.
058981,000005: ## It is part of the reconstructed source code for the
058982,000006: ## second release of the flight software for the Lunar
058983,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
058984,000008: ## It was created to fix two incorrect ephemeris constants in
058985,000009: ## Luminary 96, as described by anomaly report LNY-59.
058986,000010: ## The code has been recreated from a copy of Luminary 99
058987,000011: ## revision 001, using asterisks indicating changed lines in
058988,000012: ## the listing and Luminary Memos #83 and #85, which list
058989,000013: ## changes between Luminary 97 and 98, and 98 and 99. The
058990,000014: ## code has been adapted such that the resulting bugger words
058991,000015: ## exactly match those specified for Luminary 97 in NASA drawing
058992,000016: ## 2021152D, which gives relatively high confidence that the
058993,000017: ## reconstruction is correct.
058994,000018: ## Reference: pp. 1397-1402
058995,000019: ## Assembler: yaYUL
058996,000020: ## Contact: Ron Burkey <info@sandroid.org>.
058997,000021: ## Website: www.ibiblio.org/apollo/index.html
058998,000022: ## Mod history: 2019-07-28 MAS Created from Luminary 99.
058999,000023:
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Page 1397
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059001,000025: 22,3773 BANK 22
059002,000026: 10,2000 SETLOC RTBCODES
059003,000027: 10,2000 BANK
059004,000028:
059005,000029: 10,3573 E5,1664 EBANK= XNB
059006,000030: 10,3573 COUNT* $$/RTB
059007,000031:
059008,000032: # LOAD TIME2, TIME1 INTO MPAC:
059009,000033:
059010,000034: 10,3573 00006 LOADTIME EXTEND
059011,000035: 10,3574 30025 DCA TIME2
059012,000036: 10,3575 16055 TCF SLOAD2
059013,000037:
059014,000038: # CONVERT THE SINGLE PRECISION 2'S COMPLEMENT NUMBER ARRIVING IN MPAC (SCALED IN HALF-REVOLUTIONS) TO A
059015,000039: # DP 1'S COMPLEMENT NUMBER SCALED IN REVOLUTIONS.
059016,000040:
059017,000041: 10,3576 10154 CDULOGIC CCS MPAC
059018,000042: 10,3577 34755 CAF ZERO
059019,000043: 10,3600 13603 TCF +3
059020,000044: 10,3601 13602 NOOP
059021,000045: 10,3602 44736 CS HALF
059022,000046:
059023,000047: 10,3603 54155 TS MPAC +1
059024,000048: 10,3604 34755 CAF ZERO
059025,000049: 10,3605 56154 XCH MPAC
059026,000050: 10,3606 00006 EXTEND
059027,000051: 10,3607 74736 MP HALF
059028,000052: 10,3610 20155 DAS MPAC
059029,000053: 10,3611 16061 TCF DANZIG # MODE IS ALREADY AT DOUBLE-PRECISION
059030,000054:
059031,000055: # FORCE TP SIGN AGREEMENT IN MPAC:
059032,000056:
059033,000057: 10,3612 07257 SGNAGREE TC TPAGREE
059034,000058: 10,3613 16061 TCF DANZIG
059035,000059:
059036,000060: # CONVERT THE DP 1'S COMPLEMENT ANGLE SCALED IN REVOLUTIONS TO A SINGLE PRECISION 2'S COMPLEMENT ANGLE
059037,000061: # SCALED IN HALF-REVOLUTIONS.
059038,000062:
059039,000063: 10,3614 03644 1STO2S TC 1TO2SUB
059040,000064: 10,3615 34755 CAF ZERO
059041,000065: 10,3616 54155 TS MPAC +1
059042,000066: 10,3617 16060 TCF NEWMODE
059043,000067:
059044,000068: # DO 1STO2S ON A VECTOR OF ANGLES:
059045,000069:
059046,000070: 10,3620 03644 V1STO2S TC 1TO2SUB # ANSWER ARRIVES IN A AND MPAC.
059047,000071:
059048,000072: 10,3621 52162 DXCH MPAC +5
059049,000073: 10,3622 52155 DXCH MPAC
059050,000074: 10,3623 03644 TC 1TO2SUB
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Page 1398
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059052,000076: 10,3624 54156 TS MPAC +2
059053,000077:
059054,000078: 10,3625 52160 DXCH MPAC +3
059055,000079: 10,3626 52155 DXCH MPAC
059056,000080: 10,3627 03644 TC 1TO2SUB
059057,000081: 10,3630 54155 TS MPAC +1
059058,000082:
059059,000083: 10,3631 30161 CA MPAC +5
059060,000084: 10,3632 54154 TS MPAC
059061,000085:
059062,000086: 10,3633 34753 TPMODE CAF ONE # MODE IS TP.
059063,000087: 10,3634 16060 TCF NEWMODE
059064,000088:
059065,000089: # V1STO2S FOR 2 COMPONENT VECTOR. USED BY RR.
059066,000090:
059067,000091: 10,3635 03644 2V1STO2S TC 1TO2SUB
059068,000092: 10,3636 52160 DXCH MPAC +3
059069,000093: 10,3637 52155 DXCH MPAC
059070,000094: 10,3640 03644 TC 1TO2SUB
059071,000095: 10,3641 54001 TS L
059072,000096: 10,3642 30157 CA MPAC +3
059073,000097: 10,3643 16055 TCF SLOAD2
059074,000098:
059075,000099: # SUBROUTINE TO DO DOUBLING AND 1'S TO 2'S CONVERSION:
059076,000100:
059077,000101: 10,3644 52155 1TO2SUB DXCH MPAC # FINAL MPAC +1 UNSPECIFIED.
059078,000102: 10,3645 20001 DDOUBL
059079,000103: 10,3646 10000 CCS A
059080,000104: 10,3647 64753 AD ONE
059081,000105: 10,3650 13652 TCF +2
059082,000106: 10,3651 40000 COM # THIS WAS REVERSE OF MSU.
059083,000107:
059084,000108: 10,3652 54154 TS MPAC # AND SKIP ON OVERFLOW.
059085,000109: 10,3653 00002 TC Q
059086,000110:
059087,000111: 10,3654 50000 INDEX A # OVERFLOW UNCORRECT AND IN MSU.
059088,000112: 10,3655 34734 CAF LIMITS
059089,000113: 10,3656 26154 ADS MPAC
059090,000114: 10,3657 00002 TC Q
059091,000115:
059092,000116: # THE FOLLOWING ROUTINE INCREMENTS IN 2S COMPLEMENT THE REGISTER WHOSE ADDRESS IS IN BUF BY THE 1S COMPL.
059093,000117: # QUANTITY FOUND IN TEM2. THIS MAY BE USED TO INCREMENT DESIRED IMU AND OPTICS CDU ANGLES OR ANY OTHER 2S COMPL.
059094,000118: # (+0 UNEQUAL TO -0) QUANTITY. MAY BE CALLED BY BANKCALL/SWCALL.
059095,000119:
059096,000120: 10,3660 54142 CDUINC TS TEM2 # 1S COMPL.QUANT. ARRIVES IN ACC. STORE IT
059097,000121: 10,3661 50130 INDEX BUF
059098,000122: 10,3662 10000 CCS 0 # CHANGE 2S COMPL. ANGLE(IN BUF)INTO 1S
059099,000123: 10,3663 64753 AD ONE
059100,000124: 10,3664 13670 TCF +4
059101,000125: 10,3665 64753 AD ONE
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Page 1399
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059103,000127: 10,3666 64753 AD ONE # OVERFLOW HERE IF 2S COMPL. IS 180 DEG.
059104,000128: 10,3667 40000 COM
059105,000129:
059106,000130: 10,3670 60142 AD TEM2 # SULT MOVES FROM 2ND TO 3D QUAD. (OR BACK)
059107,000131: 10,3671 10000 CCS A # BACK TO 2S COMPL.
059108,000132: 10,3672 64753 AD ONE
059109,000133: 10,3673 13675 TCF +2
059110,000134: 10,3674 40000 COM
059111,000135: 10,3675 54142 TS TEM2 # STORE 14BIT QUANTITY WITH PRESENT SIGN
059112,000136: 10,3676 13702 TCF +4
059113,000137: 10,3677 50000 INDEX A # SIGN.
059114,000138: 10,3700 34734 CAF LIMITS # FIX IT, BY ADDING IN 37777 OR 40000
059115,000139: 10,3701 60142 AD TEM2
059116,000140:
059117,000141: 10,3702 50130 INDEX BUF
059118,000142: 10,3703 54000 TS 0 # STORE NEW ANGLE IN 2S COMPLEMENT.
059119,000143: 10,3704 00002 TC Q
059120,000144:
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Page 1400
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059122,000146: # RTB TO TORQUE GYROS, EXCEPT FOR THE CALL TO IMUSTALL. ECADR OF COMMANDS ARRIVES IN X1.
059123,000147:
059124,000148: 10,3705 50120 PULSEIMU INDEX FIXLOC # ADDRESS OF GYRO COMMANDS SHOULD BE IN X1
059125,000149: 10,3706 30046 CA X1
059126,000150: 10,3707 04616 TC BANKCALL
059127,000151: 10,3710 17323 CADR IMUPULSE
059128,000152: 10,3711 16061 TCF DANZIG
059129,000153:
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Page 1401
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059131,000155: # THE SUBROUTINE SIGNMPAC SETS C(MPAC, MPAC +1) TO SIGN(MPAC).
059132,000156: # FOR THIS, ONLY THE CONTENTS OF MPAC ARE EXAMINED. ALSO +0 YIELDS POSMAX AND -0 YIELDS NEGMAX.
059133,000157:
059134,000158: # ENTRY MAY BE BY EITHER OF THE FOLLOWING:
059135,000159: # 1. LIMIT THE SIZE OF MPAC ON INTERPRETIVE OVERFLOW:
059136,000160: # ENTRY: BOVB
059137,000161: # SIGNMPAC
059138,000162: # 2. GENERATE IN MPAC THE SIGNUM FUNCTION OF MPAC:
059139,000163: # ENTRY: RTB
059140,000164: # SIGNMPAC
059141,000165: # IN EITHER CASE, RETURN IS TO THE NEXT INTERPRETIVE INSTRUCTION IN THE CALLING SEQUENCE.
059142,000166:
059143,000167: 10,3712 00006 SIGNMPAC EXTEND
059144,000168: 10,3713 34733 DCA DPOSMAX
059145,000169: 10,3714 52155 DXCH MPAC
059146,000170: 10,3715 10000 CCS A
059147,000171: 10,3716 34755 DPMODE CAF ZERO # SETS MPAC +2 TO ZERO IN THE PROCESS
059148,000172: 10,3717 16057 TCF SLOAD2 +2
059149,000173: 10,3720 13721 TCF +1
059150,000174: 10,3721 00006 EXTEND
059151,000175: 10,3722 44733 DCS DPOSMAX
059152,000176: 10,3723 16055 TCF SLOAD2
059153,000177:
059154,000178: # RTB OP CODE NORMUNIT IS LIKE INTERPRETIVE INSTRUCTION UNIT, EXCEPT THAT IT CAN BE DEPENDED ON NOT TO BLOW
059155,000179: # UP WHEN THE VECTOR BEING UNITIZED IS VERY SMALL -- IT WILL BLOW UP WHEN ALL COMPONENTS ARE ZERO. IF NORMUNIT
059156,000180: # IS USED AND THE UPPER ORDER HALVES OF ALL COMPONENTS ARE ZERO, THE MAGNITUDE RETURNED IN 36D WILL BE TOO LARGE
059157,000181: # BY A FACTOR OF 2(13) AND THE SQUARED MAGNITUDE RETURNED AT 34D WILL BE TOO BIG BY A FACTOR OF 2(26).
059158,000182:
059159,000183: 10,3724 34753 NORMUNX1 CAF ONE
059160,000184: 10,3725 13727 TCF NORMUNIT +1
059161,000185: 10,3726 34755 NORMUNIT CAF ZERO
059162,000186: 10,3727 60120 AD FIXLOC
059163,000187: 10,3730 54156 TS MPAC +2
059164,000188: 10,3731 04616 TC BANKCALL # GET SIGN AGREEMENT IN ALL COMPONENTS
059165,000189: 10,3732 01010 CADR VECAGREE
059166,000190: 10,3733 10154 CCS MPAC
059167,000191: 10,3734 13770 TCF NOSHIFT
059168,000192: 10,3735 13737 TCF +2
059169,000193: 10,3736 13770 TCF NOSHIFT
059170,000194: 10,3737 10157 CCS MPAC +3
059171,000195: 10,3740 13770 TCF NOSHIFT
059172,000196: 10,3741 13743 TCF +2
059173,000197: 10,3742 13770 TCF NOSHIFT
059174,000198: 10,3743 10161 CCS MPAC +5
059175,000199: 10,3744 13770 TCF NOSHIFT
059176,000200: 10,3745 13747 TCF +2
059177,000201: 10,3746 13770 TCF NOSHIFT
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Page 1402
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059179,000203: 10,3747 30155 CA MPAC +1 # SHIFT ALL COMPONENTS LEFT 13
059180,000204: 10,3750 00006 EXTEND
059181,000205: 10,3751 74736 MP BIT14
059182,000206: 10,3752 20155 DAS MPAC # DAS GAINS A LITTLE ACCURACY
059183,000207: 10,3753 30160 CA MPAC +4
059184,000208: 10,3754 00006 EXTEND
059185,000209: 10,3755 74736 MP BIT14
059186,000210: 10,3756 20160 DAS MPAC +3
059187,000211: 10,3757 30162 CA MPAC +6
059188,000212: 10,3760 00006 EXTEND
059189,000213: 10,3761 74736 MP BIT14
059190,000214: 10,3762 20162 DAS MPAC +5
059191,000215: 10,3763 34761 CAF THIRTEEN
059192,000216: 10,3764 50156 INDEX MPAC +2
059193,000217: 10,3765 54045 TS 37D
059194,000218: 10,3766 04635 OFFTUNIT TC POSTJUMP
059195,000219: 10,3767 01024 CADR UNIT +1 # SKIP THE "TC VECAGREE" DONE AT UNIT
059196,000220:
059197,000221: 10,3770 34755 NOSHIFT CAF ZERO
059198,000222: 10,3771 13764 TCF OFFTUNIT -2
059199,000223:
059200,000224: # RTB VECSGNAG ... FORCES SIGN AGREEMENT OF VECTOR IN MPAC.
059201,000225:
059202,000226: 10,3772 04616 VECSGNAG TC BANKCALL
059203,000227: 10,3773 01010 CADR VECAGREE
059204,000228: 10,3774 06061 TC DANZIG
059205,000229:
059206,000230:
End of include-file RTB_OP_CODES.agc. Parent file is MAIN.agc