### FILE="Main.annotation"
## Copyright:   Public domain.
## Filename:	TVCRESTARTS.agc
## Purpose:     Part of the source code for Colossus build 237.
##              This is for the Command Module's (CM) Apollo Guidance
##              Computer (AGC), for Apollo 8.
## Assembler:   yaYUL
## Contact:     Jim Lawton <jim DOT lawton AT gmail DOT com>
## Website:     www.ibiblio.org/apollo/index.html
## Page Scans:  www.ibiblio.org/apollo/ScansForConversion/Colossus237/
## Mod history: 2011-03-06 JL	Adapted from corresponding Colossus 249 file.
##		2017-01-01 RSB	Proofed comment text using octopus/ProoferComments,
##				and fixed errors found.

## Page 913
# NAME....TVCRESTART PACKAGE,  CONSISTING OF REDOTVC, ENABL1, 2, CMDSOUT, PHSCHK2, ETC.
# LOG SECTION....TVCRESTART PACKAGE    SUBROUTINE....DAPCSM
# MOD BY ENGEL                         DATE....19 OCT, 1967

# FUNCTIONAL DESCRIPTION....

#     *RESTART-PROOFS THE TVC DAPS, INCLUDING PITCHDAP, YAWDAP,
#      TVCEXECUTIVE, ROLL DAP, TVCINIT4, TVCDAPON, AND STROKE TEST
#     *TVC RESTARTS DESERVE SPECIAL CONSIDERATION IN SEVERAL AREAS.
#      RESTART DOWN-TIME IS IMPORTANT BECAUSE OF THE TRANSIENTS INTRODUCED
#      BY THE THRUST VECTOR RETURN TO THE ACTUATOR MECHANICAL NULLS
#      FOLLOWING TVC- AND OPTICS-ERROR-COUNTER-DISENABLES (CHANNEL 12).
#      TVC    USES A MIXTURE OF WAITLIST, T5, T6, AND JOB CALLS. THERE IS
#      FILTER MEMORY (UP TO 7TH ORDER) TO BE PROTECTED IF WILD TRANSIENTS
#      ARE TO BE AVOIDED. SEVERAL COUNTERS ARE INVOLVED FOR TIMING TVC
#      EVENTS SUCH AS SWITCHOVER AND STROKE TEST STARTUPS AND RE-STARTUPS.
#      THE TVC GAINS ARE DECREMENTED. THE GIMBAL TRIM ESTIMATORS AND THE
#      BODY AXIS ATTITUDE ERROR INTEGRATORS INVOLVE DIGITAL SUMMATION.
#      DIGITAL DIFFERENTIATORS ARE INVOLVED IN THE BODY AXIS RATE ESTIMA-
#      TIONS AND IN THE OUTPUTTING OF ACTUATOR COMMANDS. THERE IS AN
#      OFFSET-TRACKER-FILTER TO PROTECT. ETC., ETC.
#     *THOSE QUANTITIES WHICH MUST BE PROTECTED ARE STORED IN TEMPORARY
#      REGISTERS AS THEY ARE COMPUTED, FOR UPDATING THE REAL REGISTERS
#      DURING COPYCYCLES.
#     *THE SEVERAL COPYCYCLES ARE EACH PROTECTED BY PHASE POINTS AT THEIR
#      BEGINNING AND AT THEIR TERMINATION. THE PHASE POINTS ARE SIMPLY
#      ..INCR.. INSTRUCTIONS,   EITHER ..INCR TVCEXPHS.. FOR COPYCYCLES
#      IN THE TVCEXECUTIVE, OR ..INCR TVCPHASE.. FOR THE PITCH AND YAW
#      COPYCYCLES. INDEXING ON EACH OF THESE POINTERS THEN PERMITS A
#      RETURN TO THE APPROPRIATE RESTART POINTS.
#     *IF A RESTART OCCURS DURING EITHER COPYCYCLE, THAT COPYCYCLE IS
#      COMPLETED. THEN THE NORMAL TVCINIT4....DAPINIT....PITCHDAP STARTUP
#      SEQUENCE IS CALLED UPON TO GET THINGS GOING AGAIN.
#     *TVC-ENABLE AND OPTICS-ERROR-COUNTER ENABLE MUST BE SET ASAP
#      (ALLOWING FOR PROCEDURAL DELAYS). THEN THE ENGINES ARE COMMANDED
#      TO THE P,YACTOFF TRIM VALUES. THE DAPS ARE THEN READY TO GO ON THE
#      AIR, WITH THE REGULAR STARTUP SEQUENCE, EITHER AT MRCLEAN FOR A
#      COMPLETE INITIALIZATION OR AT TVCINIT4 FOR A PARTIAL INITIALIZATION
#     *FOR RESTARTS PRIOR TO THE SETTING OF THE T5 BITS IN IGNOVER THE
#      PRE40.6 SECTION OF S40.6 TAKES CARE OF RE-ESTABLISHING TRIMS.
#     *IF A RESTART OCCURS DURING THE TVCEXEC....TVCEXFIN SEQUENCE THE
#      COMPUTATIONS WILL BE COMPLETED, STARTING AT THE APPROPRIATE RESTART
#      POINT, AFTER THE DAPS ARE READY TO GO ON THE AIR.
#     *IF A RESTART OCCURS PRIOR TO TVCINIT4 (TVCPHASE = -1) E.G. DURING
#      THE EARLY DAP INITIALIZATION PHASE, THE DAP STARTUP SEQUENCE IS
#      ENTERED AT MRCLEAN FOR A FULL INITIALIZATION.
#     *RESTARTS ARE NOT CRITICAL TO THE ROLL DAP PERFORMANCES HENCE THE
#      THE ROLL DAP IS MERELY RESTARTED.
#     *RESTARTS DURING A STROKE TEST (STROKER IS NON-ZERO) WILL CAUSE THE
#      STROKE TEST TO BE TERMINATED. A NEW V68 ENTRY WILL BE REQUIRED
## Page 914
#      TO GET IT GOING AGAIN (NO AUTOMATIC RESTART).
#     *REDOTVC IS REACHED FOLLOWING ANY RESTART WHICH FINDS THE T5 BITS
#      (BITS 15,14 OF FLAGWRD6) SET FOR TVC. IGNOVER PREPARES TVCPHASE =-1
#      AND TVC EXPHS = 0 JUST BEFORE SETTING THESE BITS, JUST BEFORE
#      MAKING THE T5 CALL TO TVCDAPON.  T.V.N.G. TAKES OVER THE T5 CLOCK
#      TO CALL RCSUP/RCSDAPON WHICH RESETS THE T5 BITS(FOR RCS) ON A
#      NORMAL SHUTDOWN.

# CALLING SEQUENCE....T5, IN PARTICULAR BY ELRSKIP OF FRESH START/RESTART

# NORMAL EXIT MODES....RESUME, NOQRSM, POSTJUMP (TO TVCINIT4 OR MRCLEAN)

# ALARM OR ABORT EXIT MODES....NONE

# SUBROUTINES CALLED....

#     *PCOPY+1, YCOPY+1 (PITCH AND YAW COPYCYCLES)
#     *ENABLE1,2, CMDSOUT (RE-ESTABLISH ACTUATOR TRIMS)
#     *MRCLEAN OR TVCINIT4 (TVCDAP INITIALIZATIONS)
#     *EXRSTRT AND TVCEXECUTIVE PHASE POINTS 1 THRU 9
#     *WAITLIST, IBNKCALL, POSTJUMP, ISWCALL

# OTHER INTERFACES....IGNOVER AND RCSDAPON (T5 BITS), ELRSKIP (CALLS IT)

# ERASABLE INITIALIZATION REQUIRED....

#     *T5 BITS, TVCPHASE, TVCEXPHS
#     *TVC DAP VARIABLES
#     *OPERATIONS PERFORMED BY REDOTVC ARE BASED ON THE ASSUMPTION THAT
#      THE TVC DAPS ARE RUNNING NORMALLY

# OUTPUT....

#     *PITCH AND YAW TVC DAP COPYCYCLES COMPLETED IF INTERUPTED
#     *TVCEXECUTIVE COMPLETED IF INTERUPTED
#     *STROKE TEST TERMINATED IF INTERRUPTED
#     *ACTUATOR TRIMS RE-ESTABLISHED (ACTUATORS BACK ON THE AIR)
#     *TVC DAP INITIALIZATION AS REQUIRED
#     *ALL TVC DAP OPERATIONS ON THE AIR

# DERIS....TVC TEMPORARIES IN EBANK6


		BANK	16
		SETLOC	DAPROLL
		BANK
		EBANK=	TVCPHASE

		COUNT*	$$/RSRT
REDOTVC		LXCH	BANKRUPT	# TVC RESTART PACKAGE
## Page 915
		EXTEND
		QXCH	QRUPT		# (  ..TCR..  IN  ..FINCOPY..  )

EXECPHS		CCS	TVCEXPHS	# CHECK TVCEXECUTIVE PHASE
		TCF	+2		#      MUST RESTART TVCEXECUTIVE
		TCF	TVCDAPHS	#      NO NEED TO RESTART TVCEXECUTIVE

		CAF	NINE		# 9CS DELAY TO FORCE EXRSTRT TO OCCUR
		TC	WAITLIST	#      BEFORE PITCHDAP, AFTER CMDSOUT
		EBANK=	TVCEXPHS
		2CADR	EXRSTRT


TVCDAPHS	CS	OCT37776	# CHECK BITS 15 AND 1 OF TVCPHASE TO SEE
		MASK	TVCPHASE	#      DAP RESTART LOCATION  (-1,1,2,3)
		CCS	A
		TCF	FINCOPY		#      FINISH THE COPYCYCLE FIRST
		TCF	ENABL1		#      JUST PREPARE THE OUTCOUNTERS AND GO
		TCF	TRIM/CMD	#      (RE-)DO P,YCMD INITIALIZATION FIRST


ENABL1		CAF	BIT8		# TVC ENABLE, FOLLOWED BY 40 MS (MIN) WAIT
		EXTEND			#      (ENABL1 ENTRIES..+0,- CCS, FINCOPY)
		WOR	CHAN12
		CAF	TVCADDR		# WAIT,  CALLING ENABL2  (BBCON THERE)
		TS	T5LOC
		CAF	TVCADDR +4	#      60MS  (TVCEXADR)
		TS	TIME5

		TCF	RESUME


ENABL2		LXCH	BANKRUPT	# CONTINUE PREPARATION OF OUTCOUNTERS

		CAF	BIT2		# OPTICS ERROR CNTR ENABLE, 4MS MIN WAIT
		EXTEND
		WOR	CHAN12
		CAF	TVCADDR +2	# WAIT, CALLING CMDSOUT (BBCON THERE)
		TS	T5LOC
		CAF	OCT37776	#      20MS
		TS	TIME5

		TCF	NOQRSM


CMDSOUT		LXCH	BANKRUPT	# CONTINUE PREPARATION OF OUTCOUNTERS
		EXTEND
		QXCH	QRUPT

## Page 916
		CS	ZERO		# MOST RECENT ACTUATOR COMMANDS
		AD	PCMD		#      (AVOID +0)
		TS	TVCPITCH
		CS	ZERO
		AD	YCMD
		TS	TVCYAW

		CAF	PRIO6		# RELEASE THE COUNTERS (BITS 11,12)
		EXTEND
		WOR	CHAN14

PHSCHK2		CS	TVCPHASE	# CHECK TVCPHASE AGAIN
		EXTEND
		BZMF	+3
		TC	POSTJUMP	#      IF NEGATIVE, RESTART AT MRCLEAN
		CADR	MRCLEAN		#           FOR FULL INITIALIZATION

CHKSTRK		CCS	STROKER		# CHECK FOR STROKE TEST IN PROGRESS
		TCF	TSTINITJ	# YES, KILL IT
		TCF	+2		# NO, PROCEED
		TCF	TSTINITJ	# YES, KILL IT

  +4		TC	POSTJUMP	#      IF POSITIVE OR ZERO, RESTART AT
		CADR	TVCINIT4	#           TVCINIT4 (ZEROS TVCPHASE, AND
#					            CALLS TVC DAPS)


FINCOPY		INDEX	TVCPHASE	# PICK UP THE APPROPRIATE COPYCYCLE
		CAF	TVCCADR
		TCR	ISWCALL		# RE-ENTER THE COPYCYCLE, RETURN AT END
		TCF	ENABL1		# NOW PREPARE THE OUTCOUNTERS


TRIM/CMD	EXTEND			# TVCDAPON INITIALIZATION NOT COMPLETED,
		DCA	PACTOFF		#      EG.  P,YCMD MAY NOT BE SET.  SET...
		DXCH	PCMD
		TCF	ENABL1		# NOW PREPARE THE OUTCOUNTERS


TSTINITJ	CAF	ZERO		# DISABLE STROKE TEST (-0 SHOWS PRIOR V68)
		TS	STROKER		# (+0 MEANS NEW V68 REQUIRED FOR STARTUP)


		TCF	CHKSTRK +4

EXRSTRT		INDEX	TVCEXPHS	# TVCEXECUTIVE RESTARTS....GO TO
		CAF	TVCEXADR	#      APPROPRIATE RESTART POINT
		INDEX	A
		TCF	0

## Page 917
# TVC RESTART TABLES.... ORDER IS REQUIRED.   HI-ORDER WORDS ONLY, OF 2CADRS, SINCE BBCON IS ALREADY THERE.

TVCADDR		=	TVCCADR		# TABLE OF CADRS, UNUSED LOCS FOR GENADRS
TVCCADR		GENADR	ENABL2		# (FOR T5 CALL, UNUSED TABLE LOC)
   +1		CADR	PCOPY +1	# PITCH COPYCYCLE
   +2		GENADR	CMDSOUT		# (FOR T5 CALL, UNUSED TABLE LOC)
   +3		CADR	YCOPY +1	# YAW COPYCYCLE
TVCEXADR	OCT	37772		# (UNUSED TABLE LOC, FILL WITH 60MS, T5)
   +1		GENADR	EXECCOPY +1	# TVCEXECUTIVE RESTART POINTS (ORDERED)
   +2		GENADR	SWT/COR
   +3		GENADR	SWTCOPY +1
   +4		GENADR	TEMPSET
   +5		GENADR	CORSETUP
   +6		GENADR	CORCOPY +1
   +7		GENADR	CNTRCOPY
   +8D		GENADR	STRKUP
   +9D		GENADR	STRKTCPY +1