# Copyright:    Public domain.
# Filename:     P76.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:      Hartmuth Gutsche <hgutsche@xplornet.com>.
# Website:      www.ibiblio.org/apollo.
# Pages:	pp  511-513
# Mod history:  2009-05-08 HG    Adapting from the Luminary131/ file 
#               of the same name, using Comanche055 page 
#               images 0511.jpg - 0513.jpg. 
#
# 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 511
# 1)	PROGRAM NAME -- TARGET DELTA V PROGRAM (P76).
# 2)	FUNCTIONAL DESCRIPTION -- UPON ENTRY BY ASTRONAUT ACTION, P76 FLASHES DSKY REQUESTS TO THE ASTRONAUT
#	TO PROVIDE VIA DSKY (1) THE DELTA V TO BE APPLIED TO THE OTHER VEHICLE STATE VECTOR AND (2) THE
#	TIME (TIG) AT WHICH THE OTHER VEHICLE VELOCITY WAS CHANGED BY EXECUTION OF A THRUSTING MANEUVER. THE
#	OTHER VEHICLE STATE VECTOR IS INTEGRATED TO TIG AND UPDATED BY THE ADDITION OF DELTA V (DELTA V HAVING
#	BEEN TRANSFORMED FROM LV TO REF COSYS).  USING INTEGRVS, THE PROGRAM THEN INTEGRATES THE OTHER
#	VEHICLE STATE VECTOR TO THE STATE VECTOR OF THIS VEHICLE, THUS INSURING THAT THE W-MATRIX AND BOTH VEHICLE
#	STATES CORRESPOND TO THE SAME TIME.
# 3)	ERASABLE INITIALIZATION REQUIRED -- NONE.
# 4)	CALLING SEQUENCES AND EXIT MODES -- CALLED BY ASTRONAUT REQUEST THRU DSKY V 37 E 76E.
#	EXITS BY TCF ENDOFJOB.
# 5)	OUTPUT -- OTHER VEHICLE STATE VECTOR INTEGRATED TO TIG AND INCREMENTED BY DELTA V IN REF COSYS.
#	THE PUSHLIST CONTAINS THE MATRIX BY WHICH THE INPUT DELTA V MUST BE POST-MULTIPLIED TO CONVERT FROM LV
#	TO REF COSYS.
# 6)	DEBRIS -- OTHER VEHICLE STATE VECTOR.
# 7)	SUBROUTINES CALLED -- BANKCALL, GOXDSPF, CSMPREC (OR LEMPREC), ATOPCSM (OR ATOPLEM), INTSTALL, INTWAKE, PHASCHNG
#	INTPRET, INTEGRVS, AND MINIRECT.
# 8)	FLAG USE -- MOONFLAG, CMOONFLG, INTYPFLG, RASFLAG, AND MARKCTR.

		BANK	30
		SETLOC	P76LOC
		BANK

		COUNT*	$$/P76

		EBANK=	TIG

P76		TC	UPFLAG
		ADRES	TRACKFLG

		CAF	V06N84          # FLASH LAST DELTA V.
		TC      BANKCALL        # AND WAIT FOR KEYBOARD ACTION.
	        CADR    GOFLASH
		TCF     ENDP76	
		TC	+2		# PROCEED
		TC	-5		# STORE DATA AND REPEAT FLASHING
		CAF	V06N84 +1	# FLASH VERB 06 NOUN 33, DISPLAY LAST TIG,
		TC	BANKCALL	# AND WAIT FOR KEYBOARD ACTION.
		CADR	GOFLASH
		TCF	ENDP76
		TC	+2
		TC	-5
		TC	INTPRET		# RETURN TO INTERPRETIVE CODE
		DLOAD	                # SET D(MPAC)=TIG IN CSEC B28
			TIG
		STCALL	TDEC1		# SET TDEC1=TIG FOR ORBITAL INTEGRATION
			OTHPREC
COMPMAT		VLOAD	UNIT
			RATT
# Page 512
		VCOMP			# U(-R)
		STORE	24D		# U(-R) TO 24D
		VXV	UNIT		# U(-R) X V = U(V X R)
			VATT
		STORE	18D
		VXV	UNIT		# U(V X R) X U(-R) = U((R X V) X R)
			24D
		STOVL	12D
			DELVOV
		VXM	VSL1		# V(MPAC)=DELTA V IN REFCOSYS
			12D
		VAD
			VATT
		STORE	6		# V(PD6)=VATT + DELTA V
		CALL			# PREVENT WOULD-BE USER OF ORBITAL
			INTSTALL	# INTEG FROM INTERFERING WITH UPDATING
		CALL
			P76SUB1
		VLOAD	VSR*
			6
			0,2
		STOVL	VCV
			RATT
		VSR*
			0,2
		STODL	RCV
			TIG
		STORE	TET
		CLEAR	DLOAD
			INTYPFLG
			TETTHIS
INTOTHIS	STCALL	TDEC1
			INTEGRVS
		CALL
			INTSTALL
		CALL
		        P76SUB1         # SET/CLEAR MOONFLAG
		VLOAD
			RATT1
		STORE	RRECT
		STODL	RCV
			TAT
		STOVL	TET
			VATT1
		CALL
			MINIRECT
		EXIT
		TC	PHASCHNG
		OCT	04024
# Page 513
		TC	UPFLAG
		ADRES	REINTFLG
			 
		TC	INTPRET
		CALL
			ATOPOTH
		SSP     EXIT
		        QPRET
		        OUT
		TC      BANKCALL        # PERMIT USE OF ORBITAL INTEGRATION
		CADR    INTWAKE1
OUT		EXIT
ENDP76		CAF	ZERO
		TS	MARKCTR		# CLEAR RR TRACKING MARK COUNTER
		TS      VHFCNT
		
		CAF     NEGONE
		TS      MRKBUF2         # INVALIDATE MARK BUFFER
		
		TCF	GOTOP00H

V06N84		NV	0684
		NV	0633
P76SUB1		CLEAR   SLOAD
			MOONFLAG        
                        X2
                BHIZ    SET             # X2=0...CLEAR MOONFLAG
                        +2              #   =2.....SET MOONFLAG
                        MOONFLAG
                RVQ 

