swh:1:snp:92f3f585b9ae79620ad8c41a332d6329b31fd381
Tip revision: 078c79d8734a9ed2860303a7c1662004284fe853 authored by Ron Burkey on 07 August 2022, 15:04:04 UTC
Fixed a potential string-overflow bug in yaASM. Removed timestamps from
Fixed a potential string-overflow bug in yaASM. Removed timestamps from
Tip revision: 078c79d
GIMBAL_LOCK_AVOIDANCE.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: GIMBAL_LOCK_AVOIDANCE.agc
## Purpose: A section of Sunburst revision 37, or Shepatin revision 0.
## It is part of an early development version of the software
## for Apollo Guidance Computer (AGC) on the unmanned Lunar
## Module (LM) flight Apollo 5. Sunburst 37 was the program
## upon which Don Eyles's offline development program Shepatin
## was based; the listing herein transcribed was actually for
## the equivalent revision 0 of Shepatin.
## This file is intended to be a faithful transcription, except
## that the code format has been changed to conform to the
## requirements of the yaYUL assembler rather than the
## original YUL assembler.
## Reference: pp. 620-626
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2017-05-24 MAS Created from Sunburst 120.
## 2017-06-13 RSB Transcribed.
## 2017-06-22 RSB Proofed comment text with
## octopus/ProoferComments.
## Page 620
# DETECTING GIMBAL LOCK
LOCSKIRT DLOAD ABS
COF
DSU BPL # IF (ABS(COF )-CNGL) POS, GO TO NOGIMLOC
CNGL # 0
NOGIMLOC
DLOAD DMP
COF
COF +4
SL1 PDDL
COF
DMP SL1
COF +2
PDDL DSQ
COF
SL1 VDEF # 2
STORE K1 # V1 = (COF , COF COF , COF COF ) $2
VCOMP VAD # 0 0 1 0 2
HALFA # -
STODL K2 # V2 = ((1-V1 ), -V1 , -V1 ) $2
COF +2 # 0 1 2
DCOMP PDDL
COF +4
PDDL VDEF # -
NIL # V3 = (0, COF , -COF )
STOVL K3 # 2 1
MIS +6 # - -
STORE IG # IG = MIS $2
MXV VSL1 # 3
K1 # - - - -
STODL P21 # (P21, D21, G21) = (V1, V2, V3) IG $2
G21
DSQ PDDL
D21
DSQ DAD
SQRT # 2 2
STORE RAD # RAD = SQRT(D21 D21 + G21 G21)
DSU BMN
SNGLCD # IF (RAD-SNGLCD) NEG, GO TO NOGIMLOC
NOGIMLOC
DLOAD BPL
G21
OKG21
VLOAD VCOMP # IF G21 IS NEG ...
IG # - -
STODL IG # IG =-IG, RAD =-RAD
RAD
DCOMP
STORE RAD
## Page 621
OKG21 DLOAD DAD # IF G21 IS POS....
P21
RAD # IF (ABS(P21+RAD)-SD) NEG, GO NOGIMLOC
BOV ABS
CBMCALC
DSU BMN # CBM = D21/RAD $2
SD
NOGIMLOC
CBMCALC DLOAD SR1
D21
DDV BDSU
RAD
CAM
BPL DLOAD
NOGIMLOC
MFI +12D
PDDL PDDL
MFI +6
MFI # -
VDEF VSL1 # OGF = (MFI , MFI , MFI ) $2
STODL OGF # 0 3 6
OGF
DAD BMN
CNGL # IF ((OGF ) + CNGL) NEG, GO TO ALTE
ALTE # 0
VLOAD VXV
HALFA
OGF
UNIT
STOVL E1 # E1 = UNIT(OGI X OGF)
OGF
VAD UNIT
HALFA
GOTO
STORE2 # E2 = UNIT(OGI X OGF)
SETE1 VLOAD GOTO
NIL +2
STOREE1 # E1 = (0,0,1)
ALTE VLOAD VXV
HALFA
OGF
UNIT BOV
SETE1
STOREE1 STORE E1
VXV
HALFA
PDVL VXV
OGF
E1
VAD UNIT # E2 = UNIT(E1 X OGI + OGF X E1)
## Page 622
STORE2 STADR # - - -
STORE E2 # E2 = UNIT(OGI + OGF) $2
SETPD DOT
0
IG # - -
SL1 PUSH # PD0 K2 $2
DSQ SL1
PDVL DOT # PD2 (K2 K2) $2
E1
IG
SL1 PUSH # PD4 K1 $2
DSQ SL1
PDDL DSU # PD6 (K1 K1) $2
K4SQ # = COS(D)COS(D) $2
6
PUSH DSQ # PD8 D1 $2
PDDL DMP # PD10 (D1 D1) $4
E2 # (K5)
K3S1 # SIN(D) $1
DMP SL2
0 # K2
PDDL DSQ # PD12 2 K2 K3 K5 $2
E2
SL1 BDSU # K5K5 $2 PUSH UP 2 K2 K3 K5 $2
DSU DAD
2
6
PUSH DSQ # PD12 D2 $2
PDDL DMP # PD14 (D2 D2) $4
E2
K3S1
BDSU PUSH
0 # PD16 B1 $2
DMP
4 # B1 K1 $4
SL1 PUSH # PD18 B1 K1 $2
DSQ PDDL # PD22 B1 B1 K1 K1 $4
8D
DMP PUSH # PD22 D1 D2 $4
12D
BDSU DSU
20D
10D # RSQ $4
SQRT DMP
18D
PDDL SR1 # PD24 RADICAL $8
14D
PDDL SL1 # PD26 (D2 D2) $8
20D # 4(B1 B1 K1 K1) $8
DAD # PUSH UP FOR (D2 D2) $8
## Page 623
PDDL SR1 # PD26 DENOMR (D2 D2)
22D
BDSU PUSH # PD28 NUM
20D
DAD DDV # NUM
24D # + RADICAL
26D # DENOM
BOVB SR2
SIGNMPAC
STORE C2SQP # $4
SQRT
STODL C2PP # $2
24D # NUM
BDSU DDV # PUSH UP FOR NUM, DENOM
BOVB SR2
SIGNMPAC
STORE C2SQM # $4
SQRT
STODL C2MP # $2
QUARTA # 1 $4
DSU SQRT
C2SQP
STODL C1PP # $2
QUARTA
DSU SQRT
C2SQM
STORE C1MP # $2
AXT,1 SSP
4
S1
2
NORM SETPD DLOAD
18D
16D # B1 $2
DMP* PDDL # PD18 = -Q $4
C2PP +4,1
E2
DSQ DMP*
C2SQP +4,1
SL2 BDSU
QUARTA
SQRT DMP
K4 # PD20 = -R $4
PDDL DMP*
4 # K1 $2
C1PP +4,1
ABS PDDL # PD22 AC1 $4
18D # -Q
DAD DCOMP
20D # -R
## Page 624
PDDL DSU # PD24 ANSW1 = Q + R $4
18D # -Q
20D # +R
DCOMP PUSH # PD26 ANSW2 = Q - R $4
ABS DSU
22D # AC1
ABS PDDL # PD28 ABS(ABS(ANSW2) -AC1)
24D # ANSW1
ABS DSU
22D # AC1
ABS DSU # ABS(ABS(ANSW1)-AC1)
BPL DLOAD
CKSGNAN2
24D # ANSW1
SIGNANSW BPL DLOAD
SAMEASK1
4 # K1
BMN DLOAD*
OKC2
C2PP +4,1
OPPSGNC2 DCOMP
STORE C2PP +4,1
OKC2 TIX,1 GOTO
NORM
OUTCYCLE
SAMEASK1 DLOAD BPL
4 # K1
OKC2
DLOAD* GOTO
C2PP +4,1
OPPSGNC2
CKSGNAN2 DLOAD GOTO
26D # ANSW2
SIGNANSW
OUTCYCLE SETPD VLOAD
0
COF # - -
DOT PDVL # PD0 U1 = COF.E1
E1
COF # - -
DOT PUSH # PD2 U2 = COF.E2
E2
# PICK THE NEW U WHICH IS CLOSEST TO THE OLD U
AXT,1 DMP
0
C2PP
PDDL DMP # PD4 U2 C2(0)
C1PP
0 # U1 C1(0)
DAD ABS
## Page 625
PDDL DMP # PD4 ABS(U1 C1(0) + U2 C2(0))
2
C2MP
PDDL DMP # PD6 U2 C2(1)
0
C1MP # PUSH UP U2 C2(1)
DAD ABS # ABS(U1 C1(1) + U2 C2(1))
DSU # PUSH UP 4
BMN AXC,1
JZERO
2
JZERO DLOAD* VXSC
C1PP,1
E1
PDDL* VXSC
C2PP,1
E2
VAD
UNIT # NEW COF - -
STORE COF # COF = C1 E1 + C2 E2
# NEW MANEUVER ANGLE IS
DLOAD DSQ
COF
SL1 BDSU # 2
HALFA # (1 - COF ) $2
PDDL DSQ # 0
E2
BDSU DDV # 2
QUARTA # (1 - K5 ) $4
SR1 SQRT
ARCSIN SL1
STORE AM
CLRGO # STATE SWITCH NO. 31
31D # 0(OFF) = MANEUVER WENT THRU GIMBAL LOCK
WCALC # 1(ON) = MANEUVER DID NOT GO THRU GIMLOCK
NOGIMLOC SET
31D
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
## Page 626
ARATE,1
SR
5
STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
SETGO # STATE SWITCH NO. 32
32D # 0(OFF) = CONTINUE MANEUVER
NEWDELHI +1 # 1(ON) = START MANEUVER
# THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
# LOADING RATEINDX WITH 0,2,4,6, RESPECTIVELY
ARATE 2DEC .0222222222 # =.5 DEG/SEC $ 22.5DEG/SEC
2DEC .0888888888 # = 2 DEG/SEC $ 22.5DEG/SEC
2DEC .2222222222 # = 5 DEG/SEC $ 22.5DEG/SEC
2DEC .4444444444 # =10 DEG/SEC $ 22.5DEG/SEC
ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
# 34,3513 04000 0 MANEUVER ANGLE TO MANEUVER TIME
