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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060524,000002: ## Copyright: Public domain.
060525,000003: ## Filename: DAP_INTERFACE_SUBROUTINES.agc
060526,000004: ## Purpose: A section of LUM69 revision 2.
060527,000005: ## It is part of the reconstructed source code for the flown
060528,000006: ## version of the flight software for the Lunar Module's (LM)
060529,000007: ## Apollo Guidance Computer (AGC) for Apollo 10. The code has
060530,000008: ## been recreated from a copy of Luminary revsion 069, using
060531,000009: ## changes present in Luminary 099 which were described in
060532,000010: ## Luminary memos 75 and 78. The code has been adapted such
060533,000011: ## that the resulting bugger words exactly match those specified
060534,000012: ## for LUM69 revision 2 in NASA drawing 2021152B, which gives
060535,000013: ## relatively high confidence that the reconstruction is correct.
060536,000014: ## Reference: pp. 1401-1404
060537,000015: ## Assembler: yaYUL
060538,000016: ## Contact: Ron Burkey <info@sandroid.org>.
060539,000017: ## Website: www.ibiblio.org/apollo/index.html
060540,000018: ## Mod history: 2019-07-27 MAS Created from Luminary 69.
060541,000019:
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Page 1401
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060543,000021: 20,2123 BANK 20
060544,000022: 20,2000 SETLOC DAPS3
060545,000023: 20,2000 BANK
060546,000024:
060547,000025: 20,2123 E6,1633 EBANK= CDUXD
060548,000026: 20,2123 COUNT* $$/DAPIF
060549,000027:
060550,000028: # MOD 0 DATE 11/15/66 BY GEORGE W. CHERRY
060551,000029: # MOD 1 1/23/67 MODIFICATION BY PETER ADLER
060552,000030:
060553,000031: # FUNCTIONAL DESCRIPTION
060554,000032: # HEREIN ARE A COLLECTION OF SUBROUTINES WHICH ALLOW MISSION CONTROL PROGRAMS TO CONTROL THE MODE
060555,000033: # AND INTERFACE WITH THE DAP.
060556,000034:
060557,000035: # CALLING SEQUENCES
060558,000036: # IN INTERRUPT OR WITH INTERRUPT INHIBITED
060559,000037: # TC IBNKCALL
060560,000038: # FCADR ROUTINE
060561,000039: # IN A JOB WITHOUT INTERRUPT INHIBITED
060562,000040: # INHINT
060563,000041: # TC IBNKCALL
060564,000042: # FCADR ROUTINE
060565,000043: # RELINT
060566,000044:
060567,000045: # OUTPUT
060568,000046: # SEE INDIVIDUAL ROUTINES BELOW
060569,000047:
060570,000048: # DEBRIS
060571,000049: # A, L, AND SOMETIMES MDUETEMP ODE NOT IN PULSES MODE
060572,000050:
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Page 1402
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060574,000052: # SUBROUTINE NAMES:
060575,000053: # SETMAXDB, SETMINDB, RESTORDB, PFLITEDB
060576,000054: # MODIFIED: 30 JANUARY 1968 BY P S WEISSMAN TO CREATE RESTORDB.
060577,000055: # MODIFIED: 1 MARCH 1968 BY P S WEISSMAN TO SAVE EBANK AND CREATE PFLITEDB
060578,000056:
060579,000057: # FUNCTIONAL DESCRIPTION:
060580,000058: # SETMAXDB - SET DEADBAND TO 5.0 DEGREES
060581,000059: # SETMINDB - SET DEADBAND TO 0.3 DEGREE
060582,000060: # RESTORDB - SET DEADBAND TO MAX OR MIN ACCORDING TO SETTING OF DBSELECT BIT OF DAPBOOLS
060583,000061: # PFLITEDB - SET DEADBAND TO 1.0 DEGREE AND ZERO THE COMMANDED ATTITUDE CHANGE AND COMMANDED RATE
060584,000062:
060585,000063: # ALL ENTRIES SET UP A NOVAC JOB TO DO 1/ACCS SO THAT THE TJETLAW SWITCH CURVES ARE POSITIONED TO
060586,000064: # REFLECT THE NEW DEADBAND. IT SHOULD BE NOTED THAT THE DEADBAND REFERS TO THE ATTITUDE IN THE P-, U-, AND V-AXES.
060587,000065:
060588,000066: # SUBROUTINE CALLED: NOVAC
060589,000067:
060590,000068: # CALLING SEQUENCE: SAME AS ABOVE
060591,000069: # OR TC RESTORDB +1 FROM ALLCOAST
060592,000070:
060593,000071: # DEBRIS: A, L, Q, RUPTREG1, (ITEMPS IN NOVAC)
060594,000072:
060595,000073: 20,2123 30111 RESTORDB CAE DAPBOOLS # DETERMINE CREW-SELECTED DEADBAND.
060596,000074: 20,2124 74750 MASK DBSELECT
060597,000075: 20,2125 00006 EXTEND
060598,000076: 20,2126 12140 BZF SETMINDB
060599,000077:
060600,000078: 20,2127 32151 SETMAXDB CAF WIDEDB # SET 5 DEGREE DEADBAND.
060601,000079: 20,2130 55346 +1 TS DB
060602,000080:
060603,000081: 20,2131 00006 EXTEND # SET UP JOB TO RE-POSITION SWITCH CURVES.
060604,000082: 20,2132 22070 QXCH RUPTREG1
060605,000083: 20,2133 37714 CALLACCS CAF PRIO27
060606,000084: 20,2134 05072 TC NOVAC
060607,000085: 20,2135 E6,1537 EBANK= AOSQ
060608,000086: 20,2135 02454 40106 2CADR 1/ACCJOB
060609,000087:
060610,000088: 20,2137 00070 TC RUPTREG1 # RETURN TO CALLER.
060611,000089:
060612,000090: 20,2140 32150 SETMINDB CAF NARROWDB # SET 0.3 DEGREE DEADBAND.
060613,000091: 20,2141 12130 TCF SETMAXDB +1
060614,000092:
060615,000093: 20,2142 00006 PFLITEDB EXTEND # THE RETURN FROM CALLACCS IS TO RUPTREG1.
060616,000094: 20,2143 22070 QXCH RUPTREG1
060617,000095: 20,2144 02153 TC ZATTEROR # ZERO THE ERRORS AND COMMANDED RATES.
060618,000096: 20,2145 32152 CAF POWERDB # SET DB TO 1.0 DEG.
060619,000097: 20,2146 55346 TS DB
060620,000098: 20,2147 12133 TCF CALLACCS # SET UP 1/ACCS AND RETURN TO CALLER.
060621,000099: 20,2150 00155 NARROWDB OCTAL 00155 # 0.3 DEGREE SCALED AT 45.
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Page 1403
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060623,000101: 20,2151 03434 WIDEDB OCTAL 03434 # 5.0 DEGREES SCALED AT 45.
060624,000102: 20,2152 00554 POWERDB DEC .02222 # 1.0 DEGREE SCALED AT 45.
060625,000103:
060626,000104: 20,2153 35015 ZATTEROR CAF EBANK6
060627,000105: 20,2154 56003 XCH EBANK
060628,000106: 20,2155 54001 TS L # SAVE CALLERS EBANK IN L.
060629,000107: 20,2156 30032 CAE CDUX
060630,000108: 20,2157 55633 TS CDUXD
060631,000109: 20,2160 30033 CAE CDUY
060632,000110: 20,2161 55634 TS CDUYD
060633,000111: 20,2162 30034 CAE CDUZ
060634,000112: 20,2163 55635 TS CDUZD
060635,000113: 20,2164 12170 TCF STOPRATE +3
060636,000114:
060637,000115: 20,2165 35015 STOPRATE CAF EBANK6
060638,000116: 20,2166 56003 XCH EBANK
060639,000117: 20,2167 54001 TS L # SAVE CALLERS EBANK IN L.
060640,000118: 20,2170 34755 +3 CAF ZERO
060641,000119: 20,2171 55641 TS OMEGAPD
060642,000120: 20,2172 55642 TS OMEGAQD
060643,000121: 20,2173 55643 TS OMEGARD
060644,000122: 20,2174 55636 TS DELCDUX
060645,000123: 20,2175 55637 TS DELCDUY
060646,000124: 20,2176 55640 TS DELCDUZ
060647,000125: 20,2177 55277 TS DELPEROR
060648,000126: 20,2200 55300 TS DELQEROR
060649,000127: 20,2201 55301 TS DELREROR
060650,000128: 20,2202 22003 LXCH EBANK # RESTORE CALLERS EBANK.
060651,000129: 20,2203 00002 TC Q
060652,000130:
060653,000131: # SUBROUTINE NAME: ALLCOAST
060654,000132: # WILL BE CALLED BY FRESH STARTS AND ENGINE OFF ROUTINES. .
060655,000133:
060656,000134: # CALLING SEQUENCE: (SAME AS ABOVE)
060657,000135:
060658,000136: # EXIT: RETURN TO Q.
060659,000137:
060660,000138: # SUBROUTINES CALLED: STOPRATE, RESTORDB, NOVAC
060661,000139:
060662,000140: # ZERO: (FOR ALL AXES) AOS, ALPHA, AOSTERM, OMEGAD, DELCDU, DELEROR
060663,000141:
060664,000142: # OUTPUT: DRIFTBIT/DAPBOOLS, DB, JOB TO DO 1/ACCS
060665,000143:
060666,000144: # DEBRIS: A, L, Q, RUPTREG1, RUPTREG2, (ITEMPS IN NOVAC)
060667,000145:
060668,000146: 20,2204 00006 ALLCOAST EXTEND # SAVE Q FOR RETURN
060669,000147: 20,2205 22071 QXCH RUPTREG2
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Page 1404
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060671,000149: 20,2206 02165 TC STOPRATE # CLEAR RATE INTERFACE. RETURN WITH A=0
060672,000150: 20,2207 22003 LXCH EBANK # AND L=EBANK6. SAVE CALLERS EBANK.
060673,000151: 20,2210 55537 TS AOSQ
060674,000152: 20,2211 55540 TS AOSQ +1
060675,000153: 20,2212 55541 TS AOSR
060676,000154: 20,2213 55542 TS AOSR +1
060677,000155: 20,2214 55422 TS ALPHAQ # FOR DOWNLIST.
060678,000156: 20,2215 55423 TS ALPHAR
060679,000157: 20,2216 55545 TS AOSQTERM
060680,000158: 20,2217 55546 TS AOSRTERM
060681,000159: 20,2220 22003 LXCH EBANK # RESTORE EBANK (EBANK6 NO LONGER NEEDED)
060682,000160:
060683,000161: 20,2221 40111 CS DAPBOOLS # SET UP DRIFTBIT
060684,000162: 20,2222 74744 MASK DRIFTBIT
060685,000163: 20,2223 26111 ADS DAPBOOLS
060686,000164: 20,2224 02124 TC RESTORDB +1 # RESTORE DEADBANK TO CREW-SELECTED VALUE.
060687,000165:
060688,000166: 20,2225 00071 TC RUPTREG2 # RETURN.
060689,000167:
End of include-file DAP_INTERFACE_SUBROUTINES.agc. Parent file is MAIN.agc