Source Code
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These source-code files are part of a reconstructed copy of Corona 261, the
final, flown release of the Block I Command Module (CM) Apollo Guidance Computer
(AGC) software for the AS-202 mission.
They have been created via disassembly of binary dumps of the original core rope
memory modules actually flown on the mission, part numbers 1003733-171, 1003733-241,
1003733-191, 1003733-211, 1003733-221, and 1003733-241. The source code for the Apollo
4 and 6 software, Solarium 55, was used as a starting point, since it was directly
derived from Corona and (at least in theory) only minimally modified.
Since only binary dumps (rather than listings) of Corona are available as source material,
all comments and labels are approximate.
They have been taken from other AGC programs where possible, or, in some places, written
from scratch to match what we believe would have been in the original listing.
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013625,000002: ## Copyright: Public domain.
013626,000003: ## Filename: MIDCOURSE_INITIALIZATION.agc
013627,000004: ## Purpose: A section of Corona revision 261.
013628,000005: ## It is part of the source code for the Apollo Guidance Computer
013629,000006: ## (AGC) for AS-202. No original listings of this software are
013630,000007: ## available; instead, this file was created via disassembly of
013631,000008: ## the core rope modules actually flown on the mission.
013632,000009: ## Assembler: yaYUL
013633,000010: ## Contact: Ron Burkey <info@sandroid.org>.
013634,000011: ## Website: www.ibiblio.org/apollo/index.html
013635,000012: ## Mod history: 2023-06-19 MAS Created.
013636,000013:
013637,000014: ## MAS 2023: This log section is a part of the MIDCOURSE NAVIGATION GAME, which
013638,000015: ## appears to be a very early implementation of P22, P29, and possibly some other
013639,000016: ## navigation programs. It was deleted in Solarium, and its documentation that
013640,000017: ## mentions it is nearly nonexistent outside of some MIT status reports (from
013641,000018: ## which the name of this log section is taken). Reverse-engineering it is a work
013642,000019: ## in progress; all labels and comments are modern guesses. Double-# comments
013643,000020: ## are annotations to aid in reverse engineering. Any labels that have not yet
013644,000021: ## been given modern names are given placeholders with the pattern UBB,SSSS,
013645,000022: ## where BB,SSSS is the full bank and address of the label.
013646,000023:
013647,000024: 13,6717 BANK 13
013648,000025:
013649,000026: 13,6717 03310 MIDINIT TC GRABDSP
013650,000027: 13,6720 03316 TC PREGBSY
013651,000028:
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Zero everything between DELTAV and DELVEL +5
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013653,000030: 13,6721 47010 CS LDELTAV
013654,000031: 13,6722 67011 AD LDELVEL5
013655,000032:
013656,000033: 13,6723 51302 ZEROLOP TS WORDIDX
013657,000034: 13,6724 35501 CAF ZERO
013658,000035: 13,6725 21302 INDEX WORDIDX
013659,000036: 13,6726 51001 TS DELTAV
013660,000037: 13,6727 11302 CCS WORDIDX
013661,000038: 13,6730 06723 TC ZEROLOP
013662,000039:
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Set SXT-ON flag in WASOPSET
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013664,000041: 13,6731 34502 CAF BIT13
013665,000042: 13,6732 50730 TS WASOPSET
013666,000043:
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Clear MIDFLAG and MOONFLAG
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013668,000045: 13,6733 47016 CS MINITMSK
013669,000046: 13,6734 70645 MASK STATE
013670,000047: 13,6735 50645 TS STATE
013671,000048:
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Ask user to load DELR
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013673,000050: 13,6736 37017 CAF VN2572
013674,000051: 13,6737 03106 TC NVSUB
013675,000052: 13,6740 03323 TC PRENVBSY
013676,000053: 13,6741 03165 TC DATAWAIT
013677,000054: 13,6742 07006 TC BACK2MID
013678,000055: 13,6743 06744 TC +1
013679,000056:
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Ask user to load DELVEL
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013681,000058: 13,6744 37020 CAF VN2573
013682,000059: 13,6745 03106 TC NVSUB
013683,000060: 13,6746 03323 TC PRENVBSY
013684,000061: 13,6747 03165 TC DATAWAIT
013685,000062: 13,6750 07006 TC BACK2MID
013686,000063: 13,6751 06752 TC +1
013687,000064:
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Initialize REFSMMAT to hardcoded initial values
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013689,000066: 13,6752 37012 CAF DEC17
013690,000067: 13,6753 51302 RFSMLOOP TS WORDIDX
013691,000068: 13,6754 21302 INDEX WORDIDX
013692,000069: 13,6755 37133 CAF INITRFSM
013693,000070: 13,6756 21302 INDEX WORDIDX
013694,000071: 13,6757 51051 TS REFSMMAT
013695,000072: 13,6760 11302 CCS WORDIDX
013696,000073: 13,6761 06753 TC RFSMLOOP
013697,000074:
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Initialize TE and TET with hardcoded initial value
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013699,000076: 13,6762 37021 CAF INITTET
013700,000077: 13,6763 51033 TS TE
013701,000078: 13,6764 51146 TS TET
013702,000079: 13,6765 37022 CAF INITTET +1
013703,000080: 13,6766 51034 TS TE +1
013704,000081: 13,6767 51147 TS TET +1
013705,000082:
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Initialize scales with initial values
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013707,000084: 13,6770 37014 CAF DEC18
013708,000085: 13,6771 51310 TS SCALEDT
013709,000086: 13,6772 35502 CAF FOUR
013710,000087: 13,6773 51311 TS SCALDELT
013711,000088: 13,6774 37013 CAF DEC14
013712,000089: 13,6775 51312 TS SCALER
013713,000090:
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Initialize W to hardcoded initial values
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013715,000092: 13,6776 37015 CAF DEC71
013716,000093: 13,6777 51302 WLOOP TS WORDIDX
013717,000094: 13,7000 21302 INDEX WORDIDX
013718,000095: 13,7001 37023 CAF INITW
013719,000096: 13,7002 21302 INDEX WORDIDX
013720,000097: 13,7003 51561 TS W
013721,000098: 13,7004 11302 CCS WORDIDX
013722,000099: 13,7005 06777 TC WLOOP
013723,000100:
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Back to MNG when done. TERMINATE on the load VERBs sends you straight back.
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013725,000102: 13,7006 05654 BACK2MID TC BANKCALL
013726,000103: 13,7007 50013 CADR MIDINRET
013727,000104:
013728,000105: 13,7010 01001 LDELTAV ADRES DELTAV
013729,000106: 13,7011 01165 LDELVEL5 ADRES DELVEL +5
013730,000107: 13,7012 00021 DEC17 DEC 17 B-14
013731,000108: 13,7013 00016 DEC14 DEC 14 B-14
013732,000109: 13,7014 00022 DEC18 DEC 18 B-14
013733,000110: 13,7015 00107 DEC71 DEC 71 B-14
013734,000111: 13,7016 30000 MINITMSK OCT 30000
013735,000112: 13,7017 02572 VN2572 OCT 02572
013736,000113: 13,7020 02573 VN2573 OCT 02573
013737,000114: 13,7021 02365 25204 INITTET 2DEC .077494159
013738,000115:
013739,000116: 13,7023 04000 00000 INITW 2DEC .125
013740,000117: 13,7025 00000 00000 2DEC 0 B-28
013741,000118: 13,7027 00000 00000 2DEC 0 B-28
013742,000119:
013743,000120: 13,7031 00000 00000 2DEC 0 B-28
013744,000121: 13,7033 04000 00000 2DEC .125
013745,000122: 13,7035 00000 00000 2DEC 0 B-28
013746,000123:
013747,000124: 13,7037 00000 00000 2DEC 0 B-28
013748,000125: 13,7041 00000 00000 2DEC 0 B-28
013749,000126: 13,7043 04000 00000 2DEC .125
013750,000127:
013751,000128: 13,7045 00000 00000 2DEC 0 B-28
013752,000129: 13,7047 00000 00000 2DEC 0 B-28
013753,000130: 13,7051 00000 00000 2DEC 0 B-28
013754,000131:
013755,000132: 13,7053 00000 00000 2DEC 0 B-28
013756,000133: 13,7055 00000 00000 2DEC 0 B-28
013757,000134: 13,7057 00000 00000 2DEC 0 B-28
013758,000135:
013759,000136: 13,7061 00000 00000 2DEC 0 B-28
013760,000137: 13,7063 00000 00000 2DEC 0 B-28
013761,000138: 13,7065 00000 00000 2DEC 0 B-28
013762,000139:
013763,000140: 13,7067 00000 00000 2DEC 0 B-28
013764,000141: 13,7071 00000 00000 2DEC 0 B-28
013765,000142: 13,7073 00000 00000 2DEC 0 B-28
013766,000143:
013767,000144: 13,7075 00000 00000 2DEC 0 B-28
013768,000145: 13,7077 00000 00000 2DEC 0 B-28
013769,000146: 13,7101 00000 00000 2DEC 0 B-28
013770,000147:
013771,000148: 13,7103 00000 00000 2DEC 0 B-28
013772,000149: 13,7105 00000 00000 2DEC 0 B-28
013773,000150: 13,7107 00000 00000 2DEC 0 B-28
013774,000151:
013775,000152: 13,7111 01522 13237 2DEC .051901456
013776,000153: 13,7113 00000 00000 2DEC 0 B-28
013777,000154: 13,7115 00000 00000 2DEC 0 B-28
013778,000155:
013779,000156: 13,7117 00000 00000 2DEC 0 B-28
013780,000157: 13,7121 01522 13237 2DEC .051901456
013781,000158: 13,7123 00000 00000 2DEC 0 B-28
013782,000159:
013783,000160: 13,7125 00000 00000 2DEC 0 B-28
013784,000161: 13,7127 00000 00000 2DEC 0 B-28
013785,000162: 13,7131 01522 13237 2DEC .051901456
013786,000163:
013787,000164: 13,7133 65432 45301 INITRFSM 2DEC -.326527826
013788,000165: 13,7135 63706 63306 2DEC -.378503058
013789,000166: 13,7137 00257 26526 2DEC .010724388
013790,000167:
013791,000168: 13,7141 71225 42367 2DEC -.209651023
013792,000169: 13,7143 05317 25121 2DEC .168924633
013793,000170: 13,7145 62411 42576 2DEC -.421320442
013794,000171:
013795,000172: 13,7147 12056 05734 2DEC .315318927
013796,000173: 13,7151 67032 52641 2DEC -.279642455
013797,000174: 13,7153 67310 51624 2DEC -.269024294
End of include-file MIDCOURSE_INITIALIZATION.agc. Parent file is MAIN.agc