Source Code
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These source-code files derive from a printout of Luminary 116 (the Apollo 12
Lunar Module guidance computer program), from the personal library of
original AGC developer Don Eyles, digitally photographed at archive.org,
financially sponsored by Ron Burkey, and transcribed to source code by a
team of volunteers. This colorized, syntax-highlighted form was created
by assembling that transcribed source code. Note that the full page images
are available on the
Virtual AGC project page at archive.org, while reduced-size images
are presented at the VirtualAGC project website. Report or fix any
transcription errors at
the Virtual AGC project code repository. Notations on the program listing read, in part: GAP: ASSEMBLE REVISION 116 OF AGC PROGRAM LUMINARY BY NASA 2021112-071 19:09 AUG. 11,1969Note that the date is the date of the printout, not the date of the program revision. |
015260,000002: ## Copyright: Public domain.
015261,000003: ## Filename: GIMBAL_LOCK_AVOIDANCE.agc
015262,000004: ## Purpose: A section of Luminary revision 116.
015263,000005: ## It is part of the source code for the Lunar Module's (LM)
015264,000006: ## Apollo Guidance Computer (AGC) for Apollo 12.
015265,000007: ## This file is intended to be a faithful transcription, except
015266,000008: ## that the code format has been changed to conform to the
015267,000009: ## requirements of the yaYUL assembler rather than the
015268,000010: ## original YUL assembler.
015269,000011: ## Reference: p. 365
015270,000012: ## Assembler: yaYUL
015271,000013: ## Contact: Ron Burkey <info@sandroid.org>.
015272,000014: ## Website: www.ibiblio.org/apollo/index.html
015273,000015: ## Mod history: 2017-01-22 MAS Created from Luminary 99.
015274,000016: ## 2017-02-28 f0n Modified per scan 0365.jpg
015275,000017: ## 2017-03-01 MAS Removed some outdated/extra comments.
015276,000018: ## 2017-03-01 RSB Proofed comment text by diff vs Luminary 131
015277,000019: ## but no errors found.
015278,000020:
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Page 365 |
015280,000022: 15,2050 BANK 15
015281,000023:
015282,000024: 22,2000 SETLOC KALCMON1
015283,000025: 22,2000 BANK
015284,000026:
015285,000027: # DETECTING GIMBAL LOCK
015286,000028: 22,2744 22,2744 LOCSKIRT EQUALS NOGIMLOC
015287,000029:
015288,000030: 22,2744 77614 NOGIMLOC SET
015289,000031: 22,2745 01074 CALCMAN3
015290,000032: 22,2746 70740 WCALC LXC,1 DLOAD*
015291,000033: 22,2747 01322 RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
015292,000034: 22,2750 04772 ARATE,1 # FROM A LIST OF FOUR
015293,000035: 22,2751 45002 SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
015294,000036: 22,2752 44527 DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
015295,000037: # ABOUT COF
015296,000038: 22,2753 74343 DLOAD* VXSC
015297,000039: 22,2754 04772 ARATE,1
015298,000040: 22,2755 03271 COF
015299,000041: 22,2756 17326 STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
015300,000042: 22,2757 03336 AM
015301,000043: 22,2760 55605 DMP DDV*
015302,000044: 22,2761 05002 ANGLTIME
015303,000045: 22,2762 04772 ARATE,1
015304,000046: 22,2763 77661 SR
015305,000047: 22,2764 20606 5
015306,000048: 22,2765 03334 STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
015307,000049: 22,2766 77614 SETGO
015308,000050: 22,2767 01035 CALCMAN2 # D(OFF) = CONTINUE MANEUVER
015309,000051: 22,2770 45010 NEWANGL +1 # 1(ON) = START MANEUVER
015310,000052:
015311,000053: # THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
015312,000054: # LOADING RATEINDX WITH 0, 2, 4, 6, RESPECTIVELY
015313,000055:
015314,000056: 22,2771 00221 24255 ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
015315,000057:
015316,000058: 22,2773 00554 02660 2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
015317,000059:
015318,000060: 22,2775 02660 13301 2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
015319,000061:
015320,000062: 22,2777 16161 30707 2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
015321,000063:
015322,000064: 22,3001 00003 04000 ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
015323,000065: # MANEUVER ANGLE TO MANEUVER TIME
End of include-file GIMBAL_LOCK_AVOIDANCE.agc. Parent file is MAIN.agc