Source Code
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These source-code files are part of a reconstructed copy of Luminary 163, the
first (unflown) release of the Apollo 14 Lunar Module (LM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with reconstructed source code for Luminary 173. Changes
between revision 163 and 173 were backed out, as described by Luminary memos 157
and 158. The reconstruction was verified by matching memory-bank checksums
to those listed in drawing 2021152N. Note that page numbers in the reconstructed
code match those for the baseline log section mentioned in each file's changelog;
the page numbers for a real Luminary 163 listing would be different.
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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015730,000002: ## Copyright: Public domain.
015731,000003: ## Filename: GIMBAL_LOCK_AVOIDANCE.agc
015732,000004: ## Purpose: A section of Luminary revision 163.
015733,000005: ## It is part of the reconstructed source code for the first
015734,000006: ## (unflown) release of the flight software for the Lunar
015735,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 14.
015736,000008: ## The code has been recreated from a reconstructed copy of
015737,000009: ## Luminary 173, as well as Luminary memos 157 amd 158.
015738,000010: ## It has been adapted such that the resulting bugger words
015739,000011: ## exactly match those specified for Luminary 163 in NASA
015740,000012: ## drawing 2021152N, which gives relatively high confidence
015741,000013: ## that the reconstruction is correct.
015742,000014: ## Reference: p. 369
015743,000015: ## Assembler: yaYUL
015744,000016: ## Contact: Ron Burkey <info@sandroid.org>.
015745,000017: ## Website: www.ibiblio.org/apollo/index.html
015746,000018: ## Mod history: 2019-08-21 MAS Created from Luminary 173.
015747,000019:
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Page 369
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015749,000021: 15,2050 BANK 15
015750,000022:
015751,000023: 22,2000 SETLOC KALCMON1
015752,000024: 22,2000 BANK
015753,000025:
015754,000026:
015755,000027: # DETECTING GIMBAL LOCK
015756,000028: 22,2744 22,2744 LOCSKIRT EQUALS NOGIMLOC
015757,000029:
015758,000030: 22,2744 77614 NOGIMLOC SET
015759,000031: 22,2745 01074 CALCMAN3
015760,000032: 22,2746 70740 WCALC LXC,1 DLOAD*
015761,000033: 22,2747 01322 RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
015762,000034: 22,2750 04772 ARATE,1 # FROM A LIST OF FOUR
015763,000035: 22,2751 45002 SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
015764,000036: 22,2752 44527 DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
015765,000037: # ABOUT COF
015766,000038: 22,2753 74343 DLOAD* VXSC
015767,000039: 22,2754 04772 ARATE,1
015768,000040: 22,2755 03270 COF
015769,000041: 22,2756 17325 STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
015770,000042: 22,2757 03335 AM
015771,000043: 22,2760 55605 DMP DDV*
015772,000044: 22,2761 05002 ANGLTIME
015773,000045: 22,2762 04772 ARATE,1
015774,000046: 22,2763 77661 SR
015775,000047: 22,2764 20606 5
015776,000048: 22,2765 03333 STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
015777,000049: 22,2766 77614 SETGO
015778,000050: 22,2767 01035 CALCMAN2 # 0(OFF) = CONTINUE MANEUVER
015779,000051: 22,2770 45010 NEWANGL +1 # 1(ON) = START MANEUVER
015780,000052: # THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
015781,000053: # LOADING RATEINDX WITH 0,2,4,6, RESPECTIVELY
015782,000054:
015783,000055:
015784,000056: 22,2771 00221 24255 ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
015785,000057: 22,2773 00554 02660 2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
015786,000058: 22,2775 02660 13301 2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
015787,000059: 22,2777 16161 30707 2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
015788,000060:
015789,000061: 22,3001 00003 04000 ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
015790,000062: # MANEUVER ANGLE TO MANEUVER TIME
End of include-file GIMBAL_LOCK_AVOIDANCE.agc. Parent file is MAIN.agc