swh:1:snp:cac5fb5e02e08ee7616a46f7bfbaeee022e40e15
Tip revision: 62edbcc8c6021789df156749d71229308ba4313a authored by Ronald Burkey on 08 August 2021, 00:25:00 UTC
Merge pull request #1149 from virtualagc/yagcb1_fixes
Merge pull request #1149 from virtualagc/yagcb1_fixes
Tip revision: 62edbcc
GIMBAL_LOCK_AVOIDANCE.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: GIMBAL_LOCK_AVOIDANCE.agc
## Purpose: A section of LUM69 revision 2.
## It is part of the reconstructed source code for the flown
## version of the flight software for the Lunar Module's (LM)
## Apollo Guidance Computer (AGC) for Apollo 10. The code has
## been recreated from a copy of Luminary revsion 069, using
## changes present in Luminary 099 which were described in
## Luminary memos 75 and 78. The code has been adapted such
## that the resulting bugger words exactly match those specified
## for LUM69 revision 2 in NASA drawing 2021152B, which gives
## relatively high confidence that the reconstruction is correct.
## Reference: p. 377
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2019-07-27 MAS Created from Luminary 69.
## Page 377
BANK 15
SETLOC KALCMON1
BANK
# DETECTING GIMBAL LOCK
LOCSKIRT EQUALS NOGIMLOC
NOGIMLOC SET
CALCMAN3
WCALC LXC,1 DLOAD*
RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
ARATE,1 # FROM A LIST OF FOUR
SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
# ABOUT COF
DLOAD* VXSC
ARATE,1
COF
STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
AM
DMP DDV*
ANGLTIME
ARATE,1
SR
5
STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
SETGO
CALCMAN2 # 0(OFF) = CONTINUE MANEUVER
NEWANGL +1 # 1(ON) = START MANEUVER
# THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
# LOADING RATEINDX WITH 0, 2, 4, 6, RESPECTIVELY
ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
# MANEUVER ANGLE TO MANEUVER TIME