Source Code
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These source-code files are part of a reconstructed copy of Luminary 69/2,
the flown, final release of the Apollo 10 Lunar Module (LM) Apollo Guidance Computer (AGC) software.
The reconstruction is based on the source code of Luminary 69 — i.e., the
initial, unflown version, "revision 0" — of which
a contemporary listing was available. The code was then updated by incorporating the
differences between Luminary 69 and Luminary 69/2, known from other contemporary
documentation. The only such difference is the implementation in
Luminary 69/2 of the "R-2 Lunar Potential Model", the source code for which was taken
from program Luminary 99/1 (Apollo 11 LM), of which a contemporary listing was also available.
Finally, the now-reconstructed Luminary 69/2 was then validated by assembling it to
executable form and verifying that its memory banks had the correct checksums,
known from still other contemporary documentation.
Note that page numbers in the reconstructed code match those in the original Luminary 69
program listing, or in the ORBITAL INTEGRATION log section, in Luminary 99/1. Page numbers
would certainly differ somewhat in a contemporary Luminary 69/2 listing.
Moreover, annotations that were not present in the contemporary source code have been added
to the reconstructed code to justify each change in Luminary 69/2 relative to
Luminary 69. Here's a guide to the Apollo documentation referenced in those annotations:
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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022079,000002: ## Copyright: Public domain.
022080,000003: ## Filename: RADAR_LEADIN_ROUTINES.agc
022081,000004: ## Purpose: A section of LUM69 revision 2.
022082,000005: ## It is part of the reconstructed source code for the flown
022083,000006: ## version of the flight software for the Lunar Module's (LM)
022084,000007: ## Apollo Guidance Computer (AGC) for Apollo 10. The code has
022085,000008: ## been recreated from a copy of Luminary revsion 069, using
022086,000009: ## changes present in Luminary 099 which were described in
022087,000010: ## Luminary memos 75 and 78. The code has been adapted such
022088,000011: ## that the resulting bugger words exactly match those specified
022089,000012: ## for LUM69 revision 2 in NASA drawing 2021152B, which gives
022090,000013: ## relatively high confidence that the reconstruction is correct.
022091,000014: ## Reference: pp. 502-503
022092,000015: ## Assembler: yaYUL
022093,000016: ## Contact: Ron Burkey <info@sandroid.org>.
022094,000017: ## Website: www.ibiblio.org/apollo/index.html
022095,000018: ## Mod history: 2019-07-27 MAS Created from Luminary 69.
022096,000019:
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Page 502
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022098,000021: 25,2003 BANK 25
022099,000022: 25,2000 SETLOC RRLEADIN
022100,000023: 25,2000 BANK
022101,000024:
022102,000025: 25,2003 E4,1604 EBANK= RSTACK
022103,000026:
022104,000027: # RADAR SAMPLING LOOP.
022105,000028:
022106,000029: 25,2003 COUNT* $$/RLEAD
022107,000030: 25,2003 11761 RADSAMP CCS RSAMPDT # TIMES NORMAL ONCE-PER-SECOND SAMPLING.
022108,000031: 25,2004 12006 TCF +2
022109,000032: 25,2005 15261 TCF TASKOVER # +0 INSERTED MANUALLY TERMINATES TEST.
022110,000033:
022111,000034: 25,2006 05203 TC WAITLIST
022112,000035: 25,2007 E4,1604 EBANK= RSTACK
022113,000036: 25,2007 02003 52064 2CADR RADSAMP
022114,000037:
022115,000038: 25,2011 37712 CAF PRIO25
022116,000039: 25,2012 05072 TC NOVAC
022117,000040: 25,2013 E4,1604 EBANK= RSTACK
022118,000041: 25,2013 02023 52064 2CADR DORSAMP
022119,000042:
022120,000043: 25,2015 34736 CAF BIT14 # FOR CYCLIC SAMPLING, RTSTDEX=
022121,000044: 25,2016 00006 EXTEND # RTSTLOC/2 + RTSTBASE
022122,000045: 25,2017 71760 MP RTSTLOC
022123,000046: 25,2020 61757 AD RTSTBASE # 0 FOR RR, 2 FOR LR.
022124,000047: 25,2021 55755 TS RTSTDEX
022125,000048: 25,2022 15261 TCF TASKOVER
022126,000049:
022127,000050: # DO THE ACTUAL RADAR SAMPLE.
022128,000051:
022129,000052: 25,2023 02047 DORSAMP TC VARADAR # SELECTS VARIABLE RADAR CHANNEL.
022130,000053: 25,2024 04616 TC BANKCALL
022131,000054: 25,2025 17667 CADR RADSTALL
022132,000055:
022133,000056: 25,2026 25762 INCR RFAILCNT # ADVANCE FAIL COUNTER BUT ACCEPT BAD DATA
022134,000057:
022135,000058: 25,2027 00004 DORSAMP2 INHINT
022136,000059: 25,2030 30101 CA FLAGWRD5 # DON'T UPDATE RSTACK IF IN R77.
022137,000060: 25,2031 74741 MASK R77FLBIT
022138,000061: 25,2032 10000 CCS A
022139,000062: 25,2033 12037 TCF +4
022140,000063:
022141,000064: 25,2034 53102 DXCH SAMPLSUM
022142,000065: 25,2035 51760 INDEX RTSTLOC
022143,000066: 25,2036 53605 DXCH RSTACK
022144,000067:
022145,000068: 25,2037 41760 CS RTSTLOC # CYCLE RTSTLOC.
022146,000069: 25,2040 61756 AD RTSTMAX
022147,000070: 25,2041 00006 EXTEND
022148,000071:
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Page 503
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022150,000073: 25,2042 12045 BZF +3
022151,000074: 25,2043 31760 CA RTSTLOC
022152,000075: 25,2044 64752 AD TWO # STORAGE IS DP
022153,000076: 25,2045 55760 TS RTSTLOC
022154,000077: 25,2046 15155 TCF ENDOFJOB # CONTINUOUS SAMPLING AND 2N TRIES - GONE.
022155,000078:
022156,000079: # VARIABLE RADAR DATA CALLER FOR ONE MEASUREMENT ONLY.
022157,000080:
022158,000081: 25,2047 34753 VARADAR CAF ONE # WILL BE SENT TO RADAR ROUTINE IN A BY
022159,000082: 25,2050 54133 TS BUF2 # SWCALL.
022160,000083: 25,2051 51755 INDEX RTSTDEX
022161,000084: 25,2052 32054 CAF RDRLOCS
022162,000085: 25,2053 14622 TCF SWCALL # NOT TOUCHING Q.
022163,000086:
022164,000087: 25,2054 53105 RDRLOCS CADR RRRANGE # = 0
022165,000088: 25,2055 53103 CADR RRRDOT # = 1
022166,000089: 25,2056 53101 CADR LRVELX # = 2
022167,000090: 25,2057 53077 CADR LRVELY # = 3
022168,000091: 25,2060 53075 CADR LRVELZ # = 4
022169,000092: 25,2061 53073 CADR LRALT # = 5
022170,000093:
022171,000094:
End of include-file RADAR_LEADIN_ROUTINES.agc. Parent file is MAIN.agc