Source Code
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These source-code files are part of a reconstructed copy of Artemis 071, the
first release of the Apollo 15 through 17 Command Module (CM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with source code of Artemis 072 previously transcribed
from a digitized copy of that program. The code was then updated by undoing
changes between the two versions. The reconstruction was verified by matching
memory-bank checksums to those listed in drawing 2021154-. Note that page
numbers in the reconstructed code match those on the Artemis 072 printout,
although the changed code would likely have changed page numbers for a real
Artemis 071 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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064335,000002: ## Copyright: Public domain.
064336,000003: ## Filename: RTB_OP_CODES.agc
064337,000004: ## Purpose: A section of Artemis revision 071.
064338,000005: ## It is part of the reconstructed source code for the first
064339,000006: ## release of the flight software for the Command Module's
064340,000007: ## (CM) Apollo Guidance Computer (AGC) for Apollo 15 through
064341,000008: ## 17. The code has been recreated from a copy of Artemis 072.
064342,000009: ## It has been adapted such that the resulting bugger words
064343,000010: ## exactly match those specified for Artemis 071 in NASA
064344,000011: ## drawing 2021154-, which gives relatively high confidence
064345,000012: ## that the reconstruction is correct.
064346,000013: ## Reference: 1501
064347,000014: ## Assembler: yaYUL
064348,000015: ## Contact: Ron Burkey <info@sandroid.org>.
064349,000016: ## Website: www.ibiblio.org/apollo/index.html
064350,000017: ## Mod history: 2019-08-14 MAS Created from Artemis 072.
064351,000018:
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Page 1501
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064353,000020:
064354,000021: 24,2000 SETLOC RTBCODE1
064355,000022: 24,2000 BANK
064356,000023:
064357,000024: 24,3751 E5,1713 EBANK= XNB
064358,000025: 24,3751 COUNT* $$/RTB
064359,000026:
064360,000027: # LOAD TIME2, TIME1 INTO MPAC:
064361,000028:
064362,000029: 24,3751 00006 LOADTIME EXTEND
064363,000030: 24,3752 30025 DCA TIME2
064364,000031: 24,3753 16024 TCF SLOAD2
064365,000032:
064366,000033: # CONVERT THE SINGLE PRECISION 2'S COMPLEMENT NUMBER ARRIVING IN MPAC (SCALED IN HALF-REVOLUTIONS) TO A
064367,000034: # DP 1'S COMPLEMENT NUMBER SCALED IN REVOLUTIONS.
064368,000035:
064369,000036: 24,3754 10154 CDULOGIC CCS MPAC
064370,000037: 24,3755 34772 CAF ZERO
064371,000038: 24,3756 13761 TCF +3
064372,000039: 24,3757 13760 NOOP
064373,000040: 24,3760 44753 CS HALF
064374,000041:
064375,000042: 24,3761 54155 TS MPAC +1
064376,000043: 24,3762 34772 CAF ZERO
064377,000044: 24,3763 56154 XCH MPAC
064378,000045: 24,3764 00006 EXTEND
064379,000046: 24,3765 74753 MP HALF
064380,000047: 24,3766 20155 DAS MPAC
064381,000048: 24,3767 16030 TCF DANZIG # MODE IS ALREADY AT DOUBLE-PRECISION
064382,000049:
064383,000050: 22,2000 SETLOC RTBCODES
064384,000051: 22,2000 BANK
064385,000052:
064386,000053: 22,3621 COUNT* $$/RTB
064387,000054:
064388,000055: # READ THE PIPS INTO MPAC WITHOUT CHANGING THEM:
064389,000056:
064390,000057: 22,3621 00004 READPIPS INHINT
064391,000058: 22,3622 30037 CA PIPAX
064392,000059: 22,3623 54154 TS MPAC
064393,000060: 22,3624 30040 CA PIPAY
064394,000061: 22,3625 54157 TS MPAC +3
064395,000062: 22,3626 30041 CA PIPAZ
064396,000063: 22,3627 00003 RELINT
064397,000064: 22,3630 54161 TS MPAC +5
064398,000065:
064399,000066: 22,3631 34772 CAF ZERO
064400,000067: 22,3632 54155 TS MPAC +1
064401,000068: 22,3633 54160 TS MPAC +4
064402,000069: 22,3634 54162 TS MPAC +6
064403,000070: 22,3635 16470 VECMODE TCF VMODE
064404,000071:
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Page 1502
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064406,000073:
064407,000074: # FORCE TP SIGN AGREEMENT IN MPAC:
064408,000075:
064409,000076: 22,3636 07226 SGNAGREE TC TPAGREE
064410,000077: 22,3637 16030 TCF DANZIG
064411,000078:
064412,000079: # CONVERT THE DP 1'S COMPLEMENT ANGLE SCALED IN REVOLUTIONS TO A SINGLE PRECISION 2'S COMPLEMENT ANGLE
064413,000080: # SCALED IN HALF-REVOLUTIONS.
064414,000081:
064415,000082: 22,3640 03661 1STO2S TC 1TO2SUB
064416,000083: 22,3641 34772 CAF ZERO
064417,000084: 22,3642 54155 TS MPAC +1
064418,000085: 22,3643 16027 TCF NEWMODE
064419,000086:
064420,000087: # DO 1STO2S ON A VECTOR OF ANGLES:
064421,000088:
064422,000089: 22,3644 03661 V1STO2S TC 1TO2SUB # ANSWER ARRIVES IN A AND MPAC.
064423,000090:
064424,000091: 22,3645 52162 DXCH MPAC +5
064425,000092: 22,3646 52155 DXCH MPAC
064426,000093: 22,3647 03661 TC 1TO2SUB
064427,000094: 22,3650 54156 TS MPAC +2
064428,000095:
064429,000096: 22,3651 52160 DXCH MPAC +3
064430,000097: 22,3652 52155 DXCH MPAC
064431,000098: 22,3653 03661 TC 1TO2SUB
064432,000099: 22,3654 54155 TS MPAC +1
064433,000100:
064434,000101: 22,3655 30161 CA MPAC +5
064435,000102: 22,3656 54154 TS MPAC
064436,000103:
064437,000104: 22,3657 34770 TPMODE CAF ONE # MODE IS TP.
064438,000105: 22,3660 16027 TCF NEWMODE
064439,000106:
064440,000107: # SUBROUTINE TO DO DOUBLING AND 1'S TO 2'S CONVERSION:
064441,000108:
064442,000109: 22,3661 52155 1TO2SUB DXCH MPAC # FINAL MPAC +1 UNSPECIFIED.
064443,000110: 22,3662 20001 DDOUBL
064444,000111: 22,3663 10000 CCS A
064445,000112: 22,3664 64770 AD ONE
064446,000113: 22,3665 13667 TCF +2
064447,000114: 22,3666 40000 COM # THIS WAS REVERSE OF MSU.
064448,000115:
064449,000116: 22,3667 54154 TS MPAC # AND SKIP ON OVERFLOW.
064450,000117: 22,3670 00002 TC Q
064451,000118:
064452,000119: 22,3671 50000 INDEX A # OVERFLOW UNCORRECT AND IN MSU.
064453,000120: 22,3672 34751 CAF LIMITS
064454,000121: 22,3673 26154 ADS MPAC
064455,000122: 22,3674 00002 TC Q
064456,000123:
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Page 1503
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064458,000125:
064459,000126: # THE FOLLOWING ROUTINE INCREMENTS IN 2S COMPLEMENT THE REGISTER WHOSE ADDRESS IS IN BUF BY THE 1S COMPL.
064460,000127: # QUANTITY FOUND IN TEM2. THIS MAY BE USED TO INCREMENT DESIRED IMU AND OPTICS CDU ANGLES OR ANY OTHER 2S COMPL.
064461,000128: # (+0 UNEQUAL TO -0) QUANTITY. MAY BE CALLED BY BANKCALL/SWCALL.
064462,000129:
064463,000130: 22,3675 54142 CDUINC TS TEM2 # 1S COMPL.QUANT. ARRIVES IN ACC. STORE IT
064464,000131: 22,3676 50130 INDEX BUF
064465,000132: 22,3677 10000 CCS 0 # CHANGE 2S COMPL. ANGLE(IN BUF)INTO 1S
064466,000133: 22,3700 64770 AD ONE
064467,000134: 22,3701 13705 TCF +4
064468,000135: 22,3702 64770 AD ONE
064469,000136: 22,3703 64770 AD ONE # OVERFLOW HERE IF 2S COMPL. IS 180 DEG.
064470,000137: 22,3704 40000 COM
064471,000138:
064472,000139: 22,3705 60142 AD TEM2 # SULT MOVES FROM 2ND TO 3D QUAD. (OR BACK)
064473,000140: 22,3706 10000 CCS A # BACK TO 2S COMPL.
064474,000141: 22,3707 64770 AD ONE
064475,000142: 22,3710 13712 TCF +2
064476,000143: 22,3711 40000 COM
064477,000144: 22,3712 54142 TS TEM2 # STORE 14BIT QUANTITY WITH PRESENT SIGN
064478,000145: 22,3713 13717 TCF +4
064479,000146: 22,3714 50000 INDEX A # SIGN.
064480,000147: 22,3715 34751 CAF LIMITS # FIX IT, BY ADDING IN 37777 OR 40000
064481,000148: 22,3716 60142 AD TEM2
064482,000149:
064483,000150: 22,3717 50130 INDEX BUF
064484,000151: 22,3720 54000 TS 0 # STORE NEW ANGLE IN 2S COMPLEMENT.
064485,000152: 22,3721 00002 TC Q
064486,000153:
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Page 1504
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064488,000155:
064489,000156: # RTB TO TORQUE GYROS, EXCEPT FOR THE CALL TO IMUSTALL. ECADR OF COMMANDS ARRIVES IN X1.
064490,000157:
064491,000158: 22,3722 50120 PULSEIMU INDEX FIXLOC # ADDRESS OF GYRO COMMANDS SHOULD BE IN X1
064492,000159: 22,3723 30046 CA X1
064493,000160: 22,3724 04636 TC BANKCALL
064494,000161: 22,3725 17244 CADR IMUPULSE
064495,000162: 22,3726 16030 TCF DANZIG
064496,000163:
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Page 1505
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064498,000165:
064499,000166: # EACH ROUTINE TAKES A 3X3 MATRIX STORED IN DOUBLE PRECISION IN A FIXED AREA OF ERASABLE MEMORY AND REPLACES IT
064500,000167: # WITH THE TRANSPOSE MATRIX. TRANSP1 USES LOCATIONS XNB+0,+1 THROUGH XNB+16D, 17D AND TRANSP2 USES LOCATIONS
064501,000168: # XNB1+0,+1 THROUGH XNB1+16D, 17D. EACH MATRIX IS STORED BY ROWS.
064502,000169:
064503,000170: 22,3727 02713 XNBEB ECADR XNB
064504,000171: 22,3730 02554 XNB1EB ECADR XNB1
064505,000172:
064506,000173: 22,3731 E5,1713 EBANK= XNB
064507,000174:
064508,000175: 22,3731 33727 TRANSP1 CAF XNBEB
064509,000176: 22,3732 54003 TS EBANK
064510,000177: 22,3733 53716 DXCH XNB +2
064511,000178: 22,3734 53722 DXCH XNB +6
064512,000179: 22,3735 53716 DXCH XNB +2
064513,000180:
064514,000181: 22,3736 53720 DXCH XNB +4
064515,000182: 22,3737 53730 DXCH XNB +12D
064516,000183: 22,3740 53720 DXCH XNB +4
064517,000184:
064518,000185: 22,3741 53726 DXCH XNB +10D
064519,000186: 22,3742 53732 DXCH XNB +14D
064520,000187: 22,3743 53726 DXCH XNB +10D
064521,000188: 22,3744 16030 TCF DANZIG
064522,000189:
064523,000190: 22,3745 E5,1554 EBANK= XNB1
064524,000191:
064525,000192: 22,3745 33730 TRANSP2 CAF XNB1EB
064526,000193: 22,3746 54003 TS EBANK
064527,000194: 22,3747 53557 DXCH XNB1 +2
064528,000195: 22,3750 53563 DXCH XNB1 +6
064529,000196: 22,3751 53557 DXCH XNB1 +2
064530,000197:
064531,000198: 22,3752 53561 DXCH XNB1 +4
064532,000199: 22,3753 53571 DXCH XNB1 +12D
064533,000200: 22,3754 53561 DXCH XNB1 +4
064534,000201:
064535,000202: 22,3755 53567 DXCH XNB1 +10D
064536,000203: 22,3756 53573 DXCH XNB1 +14D
064537,000204: 22,3757 53567 DXCH XNB1 +10D
064538,000205: 22,3760 16030 TCF DANZIG
064539,000206:
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Page 1506
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064541,000208:
064542,000209: # THE SUBROUTINE SIGNMPAC SETS C(MPAC, MPAC +1) TO SIGN(MPAC).
064543,000210: # FOR THIS, ONLY THE CONTENTS OF MPAC ARE EXAMINED. ALSO +0 YIELDS POSMAX AND -0 YIELDS NEGMAX.
064544,000211:
064545,000212: # ENTRY MAY BE BY EITHER OF THE FOLLOWING:
064546,000213:
064547,000214: # 1. LIMIT THE SIZE OF MPAC ON INTERPRETIVE OVERFLOW:
064548,000215: # ENTRY: BOVB
064549,000216: # SIGNMPAC
064550,000217: # 2. GENERATE IN MPAC THE SIGNUM FUNCTION OF MPAC:
064551,000218: # ENTRY: RTB
064552,000219: # SIGNMPAC
064553,000220:
064554,000221: # IN EITHER CASE, RETURN IS TO THE NEXT INTERPRETIVE INSTRUCTION IN THE CALLING SEQUENCE.
064555,000222:
064556,000223: 22,3761 00006 SIGNMPAC EXTEND
064557,000224: 22,3762 34750 DCA DPOSMAX
064558,000225: 22,3763 52155 DXCH MPAC
064559,000226: 22,3764 10000 CCS A
064560,000227: 22,3765 34772 DPMODE CAF ZERO # SETS MPAC +2 TO ZERO IN THE PROCESS
064561,000228: 22,3766 16026 TCF SLOAD2 +2
064562,000229: 22,3767 13770 TCF +1
064563,000230: 22,3770 00006 EXTEND
064564,000231: 22,3771 44750 DCS DPOSMAX
064565,000232: 22,3772 16024 TCF SLOAD2
064566,000233:
064567,000234:
End of include-file RTB_OP_CODES.agc. Parent file is MAIN.agc