### FILE="Main.annotation"
## Copyright:   Public domain.
## Filename:    GROUND_TRACKING_DETERMINATION_PROGRAM_-_P21.agc
## Purpose:     A section of a reconstructed, mixed version of Sundance
##              It is part of the reconstructed source code for the Lunar
##              Module's (LM) Apollo Guidance Computer (AGC) for Apollo 9.
##              No original listings of this program are available;
##              instead, this file was created via disassembly of dumps
##              of various revisions of Sundance core rope modules.
## Assembler:   yaYUL
## Contact:     Ron Burkey <info@sandroid.org>.
## Website:     www.ibiblio.org/apollo/index.html
## Mod history: 2020-06-17 MAS  Created from Luminary 69.

## Sundance 302

# GROUND TRACKING DETERMINATION PROGRAM P21
# PROGRAM DESCRIPTION
# MOD NO - 1
# MOD BY - N. M. NEVILLE
#
# FUNCTIONAL DECRIPTION -
#
# TO PROVIDE THE ASTRONAUT DETAILS OF THE LM OR CSM GROUND TRACK WITHOUT
# THE NEED FOR GROUND COMMUNICATION (REQUESTED BY DSKY).
# CALLING SEQUENCE -
#
#	ASTRONAUT REQUEST THROUGH DSKY V37E21E
# SUBROUTINES CALLED -
#
# GOPERF4
# GOFLASH
# THISPREC
# OTHPREC
# LAT-LONG
#
# NORMAL EXIT MODES -
#
# ASTRONAUT REQUEST TROUGH DSKY TO TERMINATE PROGRAM V34E
# ALARM OR ABORT EXIT MODES -
#
# NONE
# OUTPUT -
#
# OCTAL DISPLAY OF OPTION CODE AND VEHICLE WHOSE GROUND TRACK IS TO BE
# COMPUTED
#	OPTION CODE	00002
#	THIS		00001
#	OTHER		00002
# DECIMAL DISPLAY OF TIME TO BE INTEGRATED TO HOURS , MINUTES , SECONDS
# DECIMAL DISPLAY OF LAT,LONG,ALT
#
# ERASABLE INITIALIZATION REQUIRED
#
# AX0		2DEC	4.652459653 E-5 RADIANS		%68-69 CONSTANTS"
#
# -AY0		2DEC	2.147535898 E-5 RADIANS
#
# AZ0		2DEC	.7753206164	REVOLUTIONS
# FOR LUNAR ORBITS 504LM VECTOR IS NEEDED
#
# 504LM		2DEC	-2.700340600 E-5 RADIANS
#
# 504LM _2	2DEC	-7.514128400 E-4 RADIANS
#
# 504LM _4	2DEC	_2.553198641 E-4 RADIANS
#
# NONE
# DEBRIS
#
# CENTRALS-A,Q,L
# OTHER - THOSE USED BY THE ABOVE LISTED SUBROUTINES
# SEE LEMPREC, LAT-LONG

		SBANK=	LOWSUPER	# FOR LOW 2CADR'S.

		BANK	33
		SETLOC	P20S
		BANK

		EBANK=	P21TIME
		COUNT*	$$/P21
PROG21		CAF	ONE
		TS	OPTION2		# ASSUMED VEHICLE IS LM, R2 = 00001
		CAF	BIT2		# OPTION 2
		TC	BANKCALL
		CADR	GOPERF4
		TC	GOTOPOOH	# TERMINATE
		TC	+2		# PROCEED VALUE OF ASSUMED VEHICLE OK
		TC	-5		# R2 LOADED THROUGH DSKY
P21PROG1	CAF	V6N34		# LOAD DESIRED TIME OF LAT-LONG.
		TC	BANKCALL
		CADR	GOFLASH
		TC	GOTOPOOH	# TERM
		TC	+2		# PROCEED VALUES OK
		TC	-5		# TIME LOADED THROUGH DSKY
		TC	INTPRET
		DLOAD
			DSPTEM1
		STORE	P21TIME
		SLOAD	DSU
			OPTION2
			P21ONENN
		BHIZ	DLOAD
			P21PROG2	# VEHICLE TO BE INTEGRATED IS LEM
			P21TIME		# VEHICLE TO BE INTEGRATED IS CSM
		STCALL	TDEC1		# INTEGRATE TO TIME SPECIFIED IN TDEC
			OTHPREC		# ADJUST UNITS FOR LAT-LONG ROUTINE
P21PROGA	SLOAD	BHIZ
			X2
			P21PROG3
		VLOAD	SETGO
			RATT
			LUNAFLAG
			P21PROG4
P21PROG2	DLOAD
			P21TIME
		STCALL	TDEC1
			THISPREC
		GOTO
			P21PROGA
P21PROG3	VLOAD	CLEAR
			RATT
			LUNAFLAG
P21PROG4	STODL	ALPHAV
			TAT
		CLEAR	CALL
			ERADFLAG
			LAT-LONG
		EXIT
		CAF	V06N43		# DISPLAY LAT,LONG,ALT
		TC	BANKCALL	# LAT,LONG = 1/2 REVS B0
		CADR	GOFLASH		# ALT = KM B14
		TC	GOTOPOOH	# TERM
		TC	GOTOPOOH
		TC	INTPRET		# V32E RECYCLE
		DLOAD	DAD
			P21TIME
			600SEC		# 600 SECONDS OR 10 MIN
		STORE	DSPTEM1
		RTB
			P21PROG1
600SEC		2DEC	60000		# 10 MIN

P21ONENN	OCT	00001		# NEEDED TO DETERMINE VEHICLE
		OCT	00000		# TO BE INTEGRATED
V06N43		VN	00643
V6N34		VN	00634