https://github.com/virtualagc/virtualagc
Revision 078c79d8734a9ed2860303a7c1662004284fe853 authored by Ron Burkey on 07 August 2022, 15:04:04 UTC, committed by Ron Burkey on 07 August 2022, 15:04:04 UTC
assembly listings from yaASM and yaLEMAP. Added some debugging messages to 'make install'. Tweaked debugging messages that VirtualAGC embeds in 'simulate'. Verified buildability in Mint 21, 20, 19, 17, and verified buildability using clang in Mint 17.
1 parent 6bb1acc
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
LATITUDE_LONGITUDE_SUBROUTINES.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: LATITUDE_LONGITUDE_SUBROUTINES.agc
## Purpose: Part of the source code for Colossus 2A, AKA Comanche 055.
## It is part of the source code for the Command Module's (CM)
## Apollo Guidance Computer (AGC), for Apollo 11.
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo.
## Pages: 1236-1242
## Mod history: 2009-05-14 RSB Adapted from the Colossus249/ file of the
## same name, using Comanche055 page images.
## 2010-08-20 JL Fixed indentation of RVQ opcode on line 180.
## 2016-12-21 RSB Proofed comment text using octopus/ProoferComments
## and corrected the errors found.
## 2017-02-05 RSB Back-ported comment corrections
## identified while proofing Artemis 072.
## 2017-03-15 RSB Comment-text fixes identified in 5-way
## side-by-side diff of Luminary 69/99/116/131/210.
## This source code has been transcribed or otherwise adapted from digitized
## images of a hardcopy from the MIT Museum. The digitization was performed
## by Paul Fjeld, and arranged for by Deborah Douglas of the Museum. Many
## thanks to both. The images (with suitable reduction in storage size and
## consequent reduction in image quality as well) are available online at
## www.ibiblio.org/apollo. If for some reason you find that the images are
## illegible, contact me at info@sandroid.org about getting access to the
## (much) higher-quality images which Paul actually created.
##
## Notations on the hardcopy document read, in part:
##
## Assemble revision 055 of AGC program Comanche by NASA
## 2021113-051. 10:28 APR. 1, 1969
##
## This AGC program shall also be referred to as
## Colossus 2A
## Page 1236
# SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
#
# CALLING SEQUENCE
# L-1 CALL
# L LAT-LONG
#
# SUBROUTINES USED
# R-TO-RP, ARCTAN, SETGAMMA, SETRE
#
# ERASABLE INIT. REQ.
# AXO, -AYO, AZO, TEPHEM (SET AT LAUNCH TIME)
# ALPHAV = POSITION VECTOR METERS B-29
# MPAC -- TIME (CSECS B-28)
# ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
# LUNAFLAG=0 FOR EARTH, 1 FOR MOON
#
# OUTPUT
# LATITUDE IN LAT (REVS. B-0)
# LONGITUDE IN LONG (REVS. B-0)
# ALTITUDE IN ALT METERS B-29
BANK 30
SETLOC LATLONG
BANK
COUNT 13/LT-LG
EBANK= ALPHAV
LAT-LONG STQ SETPD
INCORPEX
0D
STOVL 6D # SAVE TIME IN 6-7D FOR R-TO-RP
ALPHAV
PUSH ABVAL # 0-5D= R FOR R-TO-RP
STODL ALPHAM # ABS. VALUE OF R FOR ALT FORMULA BELOW
ZEROVEC # SET MPAC=0 FOR EARTH, NON-ZERO FOR MOON
BOFF COS # USE COS(0) TO GET NON-ZERO IN MPAC
LUNAFLAG # 0=EARTH, 1=MOON
CALLRTRP
CALLRTRP CALL
R-TO-RP # RP VECTOR CONVERTED FROM R B-29
UNIT # UNIT RP B-1
STCALL ALPHAV # U2= 1/2 SINL FOR SETRE SUBR BELOW
SETGAMMA # SET GAMMA=B2/A2 FOR EARTH, =1 FOR MOON
CALL # SCALED B-1
SETRE # CALC RE METERS B-29
DLOAD DSQ
ALPHAV
PDDL DSQ
ALPHAV +2
## Page 1237
DAD SQRT
DMP SL1R
GAMRP
STODL COSTH # COS(LAT) B-1
ALPHAV +4
STCALL SINTH # SIN(LAT) B-1
ARCTAN
STODL LAT # LAT B0
ALPHAV
STODL COSTH # COS(LONG) B-1
ALPHAV +2
STCALL SINTH # SIN(LONG) B-1
ARCTAN
STODL LONG # LONG. REVS B-0 IN RANGE -1/2 TO 1/2
ALPHAM
DSU # ALT= R-RE METERS B-29
ERADM
STCALL ALT # EXIT WITH ALT METERS B-29
INCORPEX
## Page 1238
# SUBROUTINE TO CONVERT LAT,LONG,ALT AT GIVEN TIME TO RADIUS VECTOR
#
# CALLING SEQUENCE
# L-1 CALL
# L LALOTORV
#
# SUBROUTINES USED
# SETGAMMA, SETRE, RP-TO-R
#
# ERASABLE INIT. REQ.
# AXO, AYO, AZO, TEPHEM SET AT LAUNCH TIME
# LAT -- LATITUDE (REVS B0)
# LONG -- LONGITUDE (REVS B0)
# ALT -- ALTITUDE (METERS) B-29
# MPAC -- TIME (CSECS B-28)
# ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
# LUNAFLAG=0 FOR EARTH, 1 FOR MOON
#
# OUTPUT
# R-VECTOR IN ALPHAV (METERS B-29)
LALOTORV STQ SETPD # LAT,LONG,ALT TO R VECTOR
INCORPEX
0D
STCALL 6D # 6-7D = TIME FOR RP-TO-R
SETGAMMA # GAMMA = B2/A2 FOR EARTH, 1 FOR MOON B-1
DLOAD SIN # COS(LONG)COS(LAT) IN MPAC
LAT # UNIT RP = SIN(LONG)COS(LAT) 2-3D
DMPR PDDL # PD 2 GAMMA*SIN(LAT) 0-1D
GAMRP
LAT # 0-1D = GAMMA*SIN(LAT) B-2
COS PDDL # PD4 2-3D= COS(LAT) B-1 TEMPORARILY
LONG
SIN DMPR # PD 2
PDDL COS # PD 4 2-3D= SIN(LONG)COS(LAT) B-2
LAT
PDDL COS # PD 6 4-5D= COS(LAT) B-1 TEMPORARILY
LONG
DMPR VDEF # PD4 MPAC = COS(LONG)COS(LAT) B-2
UNIT PUSH # 0-5D = UNIT RP FOR RP-TO-R SUBR.
STCALL ALPHAV # ALPHAV +4= SINL FOR SETRE SUBR.
SETRE # RE METERS B-29
DLOAD BOFF # SET MPAC = 0 FOR EARTH, NON-ZERO FOR MOON
ZEROVEC
LUNAFLAG
CALLRPRT
COS # USE COS(0) TO GET NON-ZERO IN MPAC
CALLRPRT CALL
RP-TO-R # EXIT WITH UNIT R VECTOR IN MPAC
STODL ALPHAV
ERADM
## Page 1239
DAD VXSC # (RE + ALT)(UNIT R) METERS B-30
ALT
ALPHAV
VSL1 # R METERS B-29
STCALL ALPHAV # EXIT WITH R IN METERS B-29
INCORPEX
# SUBROUTINE TO COMPUTE EARTH RADIUS
#
# INPUT
# 1/2 SIN LAT IN ALPHAV +4
#
# OUTPUT
# EARTH RADIUS IN ERADM AND MPAC (METERS B-29)
GETERAD DLOAD DSQ
ALPHAV +4 # SIN**2(L)
SL1 BDSU
DP1/2 # COS**2(L)
DMPR BDSU
EE
DP1/2
BDDV SQRT
B2XSC
SR4R
STORE ERADM
RVQ
# THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166, B=6356784 METERS
# B2XSC = B**2 SCALED B-51
# B2/A2 = B**2/A**2 SCALED B-1
# EE = (1-B**2/A**2) SCALED B-0
B2XSC 2DEC .0179450689 # B**2 SCALED B-51
DP1/2 = XUNIT
B2/A2 2DEC .9933064884 B-1 # GAMMA= B**2/A**2 B-1
EE 2DEC 6.6935116 E-3 # (1-B**2/A**2) B-0
ERAD 2DEC 6373338 B-29 # PAD RADIUS
## Page 1240
# ARCTAN SUBROUTINE
#
# CALLING SEQUENCE
# SIN THETA IN SINTH B-1
# COS THETA IN COSTH B-1
# CALL ARCTAN
#
# OUTPUT
# ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
ARCTAN BOV
CLROVFLW
CLROVFLW DLOAD DSQ
SINTH
PDDL DSQ
COSTH
DAD
BZE SQRT
ARCTANXX # ATAN=0/0 SET THETA=0
BDDV BOV
SINTH
ATAN=90
SR1 ASIN
STORE THETA
PDDL BMN
COSTH
NEGCOS
DLOAD RVQ
NEGCOS DLOAD DCOMP
BPL DAD
NEGOUT
DP1/2
ARCTANXX STORE THETA
RVQ
NEGOUT DSU GOTO
DP1/2
ARCTANXX
ATAN=90 DLOAD SIGN
LODP1/4
SINTH
STORE THETA
RVQ
2DZERO = DPZERO
## Page 1241
# ..... SETGAMMA SUBROUTINE .....
# SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
#
# GAMMA = B**2/A**2 FOR EARTH (B-1)
# GAMMA = 1 FOR MOON (B-1)
#
# CALLING SEQUENCE
# L CALL
# L+1 SETGAMMA
#
# INPUT
# LUNAFLAG=0 FOR EARTH, =1 FOR MOON
#
# OUTPUT
# GAMMA IN GAMRP (B-1)
SETGAMMA DLOAD BOFF # BRANCH FOR EARTH
B2/A2 # EARTH GAMMA
LUNAFLAG
SETGMEX
SLOAD
1B1 # MOON GAMMA
SETGMEX STORE GAMRP
RVQ
GAMRP = 8D
## Page 1242
# ..... SETRE SUBROUTINE .....
# SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
#
# RE = RM FOR MOON
# RE = RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
#
# CALLING SEQUENCE
# L CALL
# L+1 SETRE
#
# SUBROUTINES USED
# GETERAD
#
# INPUT
# ERADFLAG = 0 FOR FIXED RE, 1 FOR COMPUTED RE
# ALPHAV +4 = 1/2 SINL IF GETERAD IS CALLED
# LUNAFLAG = 0 FOR EARTH, =1 FOR MOON
#
# OUTPUT
# ERADM = 504RM FOR MOON (METERS B-29)
# ERADM = ERAD OR COMPUTED RF FOR EARTH (METERS B-29)
SETRE STQ DLOAD
SETREX
504RM
BON DLOAD # BRANCH FOR MOON
LUNAFLAG
TSTRLSRM
ERAD
BOFF CALL # ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED
ERADFLAG
SETRXX
GETERAD
SETRXX STCALL ERADM # EXIT WITH RE OR RM METERS B-29
SETREX
TSTRLSRM BON VLOAD # ERADFLAG=0, SET R0=RLS
ERADFLAG # =1 R0=RM
SETRXX
RLS
ABVAL SR2R # SCALE FROM B-27 TO B-29
GOTO
SETRXX
SETREX = S2
504RM 2DEC 1738090 B-29 # METERS B-29 (MOON RADIUS)
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