Source Code
|
These source-code files are part of a reconstructed copy of LM131 revision 1,
the final release of the Apollo 13 Lunar Module (LM) Apollo Guidance Computer
(AGC) software.
The source reconstruction began with source code of Luminary 131 previously
transcribed from a digitized copy of that program. A dump of the flight spare
core rope memory module B5, part number 2010802-171, serial number RAY 411,
was obtained. This module is the only module different between Luminary 131
and LM131 revision 1. The dump was disassembled and all changes were incorporated
into these source files. Note that page numbers in the reconstructed code match
those on the Luminary 131 printout, although the changed code would likely have
changed page numbers for a real LM131 revision 1 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.
|
058455,000002: ## Copyright: Public domain.
058456,000003: ## Filename: RTB_OP_CODES.agc
058457,000004: ## Purpose: A section of LM131 revision 1.
058458,000005: ## It is part of the reconstructed source code for the final
058459,000006: ## release of the flight software for the Lunar Module's (LM)
058460,000007: ## Apollo Guidance Computer (AGC) for Apollo 13. The code has
058461,000008: ## been reconstructed from a listing of Luminary 131 and a dump
058462,000009: ## of a core rope memory module B5, part number 2010802-171,
058463,000010: ## which is the only module different between LM131 revision 1
058464,000011: ## and Luminary 131. The executable generated from this source
058465,000012: ## has been verified against the module dump, so while the names,
058466,000013: ## comments, and ordering may not be exactly correct, the
058467,000014: ## resulting binary is.
058468,000015: ## Reference: pp. 1389-1394
058469,000016: ## Assembler: yaYUL
058470,000017: ## Contact: Ron Burkey <info@sandroid.org>.
058471,000018: ## Website: www.ibiblio.org/apollo/index.html
058472,000019: ## Mod history: 2022-10-28 MAS Created from Luminary 131.
058473,000020:
|
|
Page 1389
|
058475,000022: 22,3773 BANK 22
058476,000023: 10,2000 SETLOC RTBCODES
058477,000024: 10,2000 BANK
058478,000025:
058479,000026: 10,3574 E5,1664 EBANK= XNB
058480,000027: 10,3574 COUNT* $$/RTB
058481,000028:
058482,000029: # LOAD TIME2, TIME1 INTO MPAC:
058483,000030:
058484,000031: 10,3574 00006 LOADTIME EXTEND
058485,000032: 10,3575 30025 DCA TIME2
058486,000033: 10,3576 16060 TCF SLOAD2
058487,000034:
058488,000035: # CONVERT THE SINGLE PRECISION 2'S COMPLEMENT NUMBER ARRIVING IN MPAC (SCALED IN HALF-REVOLUTIONS) TO A
058489,000036: # DP 1'S COMPLEMENT NUMBER SCALED IN REVOLUTIONS.
058490,000037:
058491,000038: 10,3577 10154 CDULOGIC CCS MPAC
058492,000039: 10,3600 34755 CAF ZERO
058493,000040: 10,3601 13604 TCF +3
058494,000041: 10,3602 13603 NOOP
058495,000042: 10,3603 44736 CS HALF
058496,000043:
058497,000044: 10,3604 54155 TS MPAC +1
058498,000045: 10,3605 34755 CAF ZERO
058499,000046: 10,3606 56154 XCH MPAC
058500,000047: 10,3607 00006 EXTEND
058501,000048: 10,3610 74736 MP HALF
058502,000049: 10,3611 20155 DAS MPAC
058503,000050: 10,3612 16064 TCF DANZIG # MODE IS ALREADY AT DOUBLE-PRECISION
058504,000051:
058505,000052: # FORCE TP SIGN AGREEMENT IN MPAC:
058506,000053:
058507,000054: 10,3613 07262 SGNAGREE TC TPAGREE
058508,000055: 10,3614 16064 TCF DANZIG
058509,000056:
058510,000057: # CONVERT THE DP 1'S COMPLEMENT ANGLE SCALED IN REVOLUTIONS TO A SINGLE PRECISION 2'S COMPLEMENT ANGLE
058511,000058: # SCALED IN HALF-REVOLUTIONS.
058512,000059:
058513,000060: 10,3615 03645 1STO2S TC 1TO2SUB
058514,000061: 10,3616 34755 CAF ZERO
058515,000062: 10,3617 54155 TS MPAC +1
058516,000063: 10,3620 16063 TCF NEWMODE
058517,000064:
058518,000065: # DO 1STO2S ON A VECTOR OF ANGLES:
058519,000066:
058520,000067: 10,3621 03645 V1STO2S TC 1TO2SUB # ANSWER ARRIVES IN A AND MPAC.
058521,000068:
058522,000069: 10,3622 52162 DXCH MPAC +5
058523,000070: 10,3623 52155 DXCH MPAC
058524,000071: 10,3624 03645 TC 1TO2SUB
|
|
Page 1390
|
058526,000073: 10,3625 54156 TS MPAC +2
058527,000074:
058528,000075: 10,3626 52160 DXCH MPAC +3
058529,000076: 10,3627 52155 DXCH MPAC
058530,000077: 10,3630 03645 TC 1TO2SUB
058531,000078: 10,3631 54155 TS MPAC +1
058532,000079:
058533,000080: 10,3632 30161 CA MPAC +5
058534,000081: 10,3633 54154 TS MPAC
058535,000082:
058536,000083: 10,3634 34753 TPMODE CAF ONE # MODE IS TP.
058537,000084: 10,3635 16063 TCF NEWMODE
058538,000085:
058539,000086: # V1STO2S FOR 2 COMPONENT VECTOR. USED BY RR.
058540,000087:
058541,000088: 10,3636 03645 2V1STO2S TC 1TO2SUB
058542,000089: 10,3637 52160 DXCH MPAC +3
058543,000090: 10,3640 52155 DXCH MPAC
058544,000091: 10,3641 03645 TC 1TO2SUB
058545,000092: 10,3642 54001 TS L
058546,000093: 10,3643 30157 CA MPAC +3
058547,000094: 10,3644 16060 TCF SLOAD2
058548,000095:
058549,000096: # SUBROUTINE TO DO DOUBLING AND 1'S TO 2'S CONVERSION:
058550,000097:
058551,000098: 10,3645 52155 1TO2SUB DXCH MPAC # FINAL MPAC +1 UNSPECIFIED.
058552,000099: 10,3646 20001 DDOUBL
058553,000100: 10,3647 10000 CCS A
058554,000101: 10,3650 64753 AD ONE
058555,000102: 10,3651 13653 TCF +2
058556,000103: 10,3652 40000 COM # THIS WAS REVERSE OF MSU.
058557,000104:
058558,000105: 10,3653 54154 TS MPAC # AND SKIP ON OVERFLOW.
058559,000106: 10,3654 00002 TC Q
058560,000107:
058561,000108: 10,3655 50000 INDEX A # OVERFLOW UNCORRECT AND IN MSU.
058562,000109: 10,3656 34734 CAF LIMITS
058563,000110: 10,3657 26154 ADS MPAC
058564,000111: 10,3660 00002 TC Q
058565,000112:
058566,000113: # THE FOLLOWING ROUTINE INCREMENTS IN 2S COMPLEMENT THE REGISTER WHOSE ADDRESS IS IN BUF BY THE 1S COMPL.
058567,000114: # QUANTITY FOUND IN TEM2. THIS MAY BE USED TO INCREMENT DESIRED IMU AND OPTICS CDU ANGLES OR ANY OTHER 2S COMPL.
058568,000115: # (+0 UNEQUAL TO -0) QUANTITY. MAY BE CALLED BY BANKCALL/SWCALL.
058569,000116:
058570,000117: 10,3661 54142 CDUINC TS TEM2 # 1S COMPL. QUANT. ARRIVES IN ACC. STORE IT
058571,000118: 10,3662 50130 INDEX BUF
058572,000119: 10,3663 10000 CCS 0 # CHANGE 2S COMPL. ANGLE(IN BUF)INTO 1S
058573,000120: 10,3664 64753 AD ONE
058574,000121: 10,3665 13671 TCF +4
058575,000122: 10,3666 64753 AD ONE
|
|
Page 1391
|
058577,000124: 10,3667 64753 AD ONE # OVERFLOW HERE IF 2S COMPL. IS 180 DEG.
058578,000125: 10,3670 40000 COM
058579,000126:
058580,000127: 10,3671 60142 AD TEM2 # SULT MOVES FROM 2ND TO 3D QUAD. (OR BACK)
058581,000128: 10,3672 10000 CCS A # BACK TO 2S COMPL.
058582,000129: 10,3673 64753 AD ONE
058583,000130: 10,3674 13676 TCF +2
058584,000131: 10,3675 40000 COM
058585,000132: 10,3676 54142 TS TEM2 # STORE 14BIT QUANTITY WITH PRESENT SIGN
058586,000133: 10,3677 13703 TCF +4
058587,000134: 10,3700 50000 INDEX A # SIGN.
058588,000135: 10,3701 34734 CAF LIMITS # FIX IT, BY ADDING IN 37777 OR 40000
058589,000136: 10,3702 60142 AD TEM2
058590,000137:
058591,000138: 10,3703 50130 INDEX BUF
058592,000139: 10,3704 54000 TS 0 # STORE NEW ANGLE IN 2S COMPLEMENT.
058593,000140: 10,3705 00002 TC Q
058594,000141:
|
|
Page 1392
|
058596,000143: # RTB TO TORQUE GYROS, EXCEPT FOR THE CALL TO IMUSTALL. ECADR OF COMMANDS ARRIVES IN X1.
058597,000144:
058598,000145: 10,3706 50120 PULSEIMU INDEX FIXLOC # ADDRESS OF GYRO COMMANDS SHOULD BE IN X1
058599,000146: 10,3707 30046 CA X1
058600,000147: 10,3710 04616 TC BANKCALL
058601,000148: 10,3711 17314 CADR IMUPULSE
058602,000149: 10,3712 16064 TCF DANZIG
058603,000150:
|
|
Page 1393
|
058605,000152: # THE SUBROUTINE SIGNMPAC SETS C(MPAC, MPAC +1) TO SIGN(MPAC).
058606,000153: # FOR THIS, ONLY THE CONTENTS OF MPAC ARE EXAMINED. ALSO +0 YIELDS POSMAX AND -0 YIELDS NEGMAX.
058607,000154:
058608,000155: # ENTRY MAY BE BY EITHER OF THE FOLLOWING:
058609,000156: # 1. LIMIT THE SIZE OF MPAC ON INTERPRETIVE OVERFLOW:
058610,000157: # ENTRY: BOVB
058611,000158: # SIGNMPAC
058612,000159: # 2. GENERATE IN MPAC THE SIGNUM FUNCTION OF MPAC:
058613,000160: # ENTRY: RTB
058614,000161: # SIGNMPAC
058615,000162: # IN EITHER CASE, RETURN IS TO THE NEXT INTERPRETIVE INSTRUCTION IN THE CALLING SEQUENCE.
058616,000163:
058617,000164: 10,3713 00006 SIGNMPAC EXTEND
058618,000165: 10,3714 34733 DCA DPOSMAX
058619,000166: 10,3715 52155 DXCH MPAC
058620,000167: 10,3716 10000 CCS A
058621,000168: 10,3717 34755 DPMODE CAF ZERO # SETS MPAC +2 TO ZERO IN THE PROCESS
058622,000169: 10,3720 16062 TCF SLOAD2 +2
058623,000170: 10,3721 13722 TCF +1
058624,000171: 10,3722 00006 EXTEND
058625,000172: 10,3723 44733 DCS DPOSMAX
058626,000173: 10,3724 16060 TCF SLOAD2
058627,000174:
058628,000175: # RTB OP CODE NORMUNIT IS LIKE INTERPRETIVE INSTRUCTION UNIT, EXCEPT THAT IT CAN BE DEPENDED ON NOT TO BLOW
058629,000176: # UP WHEN THE VECTOR BEING UNITIZED IS VERY SMALL -- IT WILL BLOW UP WHEN ALL COMPONENTS ARE ZERO. IF NORMUNIT
058630,000177: # IS USED AND THE UPPER ORDER HALVES OF ALL COMPONENTS ARE ZERO, THE MAGNITUDE RETURNED IN 36D WILL BE TOO LARGE
058631,000178: # BY A FACTOR OF 2(13) AND THE SQUARED MAGNITUDE RETURNED AT 34D WILL BE TOO BIG BY A FACTOR OF 2(26).
058632,000179:
058633,000180: 10,3725 34753 NORMUNX1 CAF ONE
058634,000181: 10,3726 13730 TCF NORMUNIT +1
058635,000182: 10,3727 34755 NORMUNIT CAF ZERO
058636,000183: 10,3730 60120 AD FIXLOC
058637,000184: 10,3731 54156 TS MPAC +2
058638,000185: 10,3732 04616 TC BANKCALL # GET SIGN AGREEMENT IN ALL COMPONENTS
058639,000186: 10,3733 01010 CADR VECAGREE
058640,000187: 10,3734 10154 CCS MPAC
058641,000188: 10,3735 13771 TCF NOSHIFT
058642,000189: 10,3736 13740 TCF +2
058643,000190: 10,3737 13771 TCF NOSHIFT
058644,000191: 10,3740 10157 CCS MPAC +3
058645,000192: 10,3741 13771 TCF NOSHIFT
058646,000193: 10,3742 13744 TCF +2
058647,000194: 10,3743 13771 TCF NOSHIFT
058648,000195: 10,3744 10161 CCS MPAC +5
058649,000196: 10,3745 13771 TCF NOSHIFT
058650,000197: 10,3746 13750 TCF +2
058651,000198: 10,3747 13771 TCF NOSHIFT
|
|
Page 1394
|
058653,000200: 10,3750 30155 CA MPAC +1 # SHIFT ALL COMPONENTS LEFT 13
058654,000201: 10,3751 00006 EXTEND
058655,000202: 10,3752 74736 MP BIT14
058656,000203: 10,3753 20155 DAS MPAC # DAS GAINS A LITTLE ACCURACY
058657,000204: 10,3754 30160 CA MPAC +4
058658,000205: 10,3755 00006 EXTEND
058659,000206: 10,3756 74736 MP BIT14
058660,000207: 10,3757 20160 DAS MPAC +3
058661,000208: 10,3760 30162 CA MPAC +6
058662,000209: 10,3761 00006 EXTEND
058663,000210: 10,3762 74736 MP BIT14
058664,000211: 10,3763 20162 DAS MPAC +5
058665,000212: 10,3764 34761 CAF THIRTEEN
058666,000213: 10,3765 50156 INDEX MPAC +2
058667,000214: 10,3766 54045 TS 37D
058668,000215: 10,3767 04635 OFFTUNIT TC POSTJUMP
058669,000216: 10,3770 01024 CADR UNIT +1 # SKIP THE "TC VECAGREE" DONE AT UNIT
058670,000217:
058671,000218: 10,3771 34755 NOSHIFT CAF ZERO
058672,000219: 10,3772 13765 TCF OFFTUNIT -2
058673,000220:
058674,000221: # RTB VECSGNAG ... FORCES SIGN AGREEMENT OF VECTOR IN MPAC.
058675,000222:
058676,000223: 10,3773 04616 VECSGNAG TC BANKCALL
058677,000224: 10,3774 01010 CADR VECAGREE
058678,000225: 10,3775 06064 TC DANZIG
058679,000226:
058680,000227:
End of include-file RTB_OP_CODES.agc. Parent file is MAIN.agc