Apollo-11/Comanche055/SXTMARK.agc

# Copyright:	Public domain.
# Filename:	SXTMARK.agc
# Purpose:	Part of the source code for Comanche, build 055. It
#		is part of the source code for the Command Module's
#		(CM) Apollo Guidance Computer (AGC), Apollo 11.
# Assembler:	yaYUL
# Reference:	pp. 222-235
# Contact:	Ron Burkey <info@sandroid.org>,
#  		Fabrizio Bernardini <fabrizio@spacecraft.it>
# Website:	http://www.ibiblio.org/apollo.
# Mod history:	16/05/09 FB	Transcription Batch 2 Assignment.
#
# The contents of the "Comanche055" files, in general, are transcribed
# from scanned documents.
#
#	Assemble revision 055 of AGC program Comanche by NASA
#	2021113-051.  April 1, 1969.
#
#	This AGC program shall also be referred to as Colossus 2A
#
#	Prepared by
#			Massachusetts Institute of Technology
#			75 Cambridge Parkway
#			Cambridge, Massachusetts
#
#	under NASA contract NAS 9-4065.
#
# Refer directly to the online document mentioned above for further
# information.  Please report any errors to info@sandroid.org.

# Page 222
# PROGRAM NAME - SXTMARK					DATE- 5 APRIL 1967
# PROGRAM MODIFIED BY 258/278 PROGRAMMERS		       LOG SECTION SXTMARK
# MOD BY- R. MELANSON TO ADD DOCUMENTATION		 ASSEMBLY SUNDISK REV. 116

# FUNCTIONAL DESCRIPTION-
#	SXTMARK IS CALLED FROM INTERNAL ROUTINES WHICH MAY REQUIRE STAR OR LANDMARK MARKINGS BY THE ASTRONAUT.  IF
#	THE MARK SYSTEM IS NOT IN USE, SXTMARK RESERVES A VAC AREA FOR MARKING AND REQUESTS EXECUTION OF THE MKVB51
#	ROUTINE VIA THE EXECUTIVE JOB PRIORITY LIST.  R21 USES THIS ROUTINE TO DETERMINE IF THE MARK SYSTEM CAN BE
#	USED.  IF YES, SXTMARK RETURNS TO R21 TO PERFORM ITS OWN MARK REQUESTS VIA THE V51 FLASH.

# CALLING SEQUENCE-

#	CAF	(NO. MARK REQUESTS IN BITS 1-3 OF A)
#	TC	BANKCALL
#	CADR	SXTMARK

# NORMAL EXIT MODE-
#	SWRETURN

# ALARM OR ABORT EXIT MODE-
#	ABORT

# OUTPUT-
#	1) MARKSTAT CONTAINS MARK VALUE (BITS 14-12) AND VAC AREA ADDRESS
#	2) QPRET = VAC AREA POINTER VALUE
#	3) 1ST WORD OF RESERVED VAC AREA SET TO +0
#	4) PRIO32 PLACED IN A REGISTER

# ERASABLE INITIALIZATION-
#	1) BITS 1-3 OF A = NO. MARKS REQUESTED
#	2) BITS 2,3 OF EXTVBACT =0
#	3) A VAC AREA MUST BE AVAILABLE (WORD 1 = ADDRESS OF VAC AREA)

# DEBRIS-
#	A,Q,L,RUPTREG1,MARKSTAT,QPRET,BIT2 OF EXTVBACT

		BANK	13
		SETLOC	SXTMARKE
		BANK

		EBANK=	MRKBUF1
		COUNT	07/SXTMK

SXTMARK		INHINT
		TS	RUPTREG1		# NUMBER OF MARKS WANTED

		CAF	SIX			# BIT2 = MARKING SYSTEM IN USE
		MASK	EXTVBACT		# BIT3 = EXTENDED VERB IN PROGRESS
		CCS	A
		TC	MKABORT			# SET THEREFORE ABORT
# Page 223
		CAF	BIT2			# NOT SET
		ADS	EXTVBACT		# SET IT, RESET IN ENDMARK
		TC	MARKOK			# YES, FIND VAC AREA

MKABORT		TC	BAILOUT
		OCT	01211
MARKOK		CCS	VAC1USE			# FIND VAC AREA
		TC	MKVACFND
		CCS	VAC2USE
		TC	MKVACFND
		CCS	VAC3USE
		TC	MKVACFND
		CCS	VAC4USE
		TC	MKVACFND
		CCS	VAC5USE
		TC	MKVACFND
		TC	BAILOUT
		OCT	01207

MKVACFND	AD	TWO			# ADDRESS OF VAC AREA
		TS	MARKSTAT
		INDEX	A
		TS	QPRET			# STORE NEXT AVAILABLE MARK SLOT

		CAF	ZERO			# STORE VAC AREA OCCUPIED
		INDEX	MARKSTAT
		TS	0	-1

		TC	CHECKMM			# BACKUP MARK ROUTINE USES SXTMARK
		MM	53
		TCF	+2
		TCF	SWRETURN
		TC	CHECKMM
		MM	54
		TCF	+2
		TCF	SWRETURN
		CAF	BIT12			# DESIRED NUMBER OF MARKS IN 12-14
		EXTEND
		MP	RUPTREG1
		XCH	L
		ADS	MARKSTAT

		CAF	PRIO32			# ENTER MARK JOB
		TC	NOVAC
		EBANK=	MARKSTAT
		2CADR	MKVB51

		RELINT
		TCF	SWRETURN		# SAME AS MODEEXIT

# Page 224
# PROGRAM NAME - MKRELEAS					DATE- 5 APRIL 1967
# PROGRAM MODIFIED BY 248/278 PROGRAMMERS		       LOG SECTION SXTMARK
# MOD BY- R. MELANSON TO ADD DOCUMENTATION		 ASSEMBLY SUNDISK REV. 116

# FUNCTIONAL DESCRIPTION-
#	MKRELEAS IS EXECUTED BY INTERNAL ROUTINES TO RELEASE THE MARK SYSTEM TO MAKE IT AVAILABLE TO OTHER INTERNAL
#	SYSTEM ROUTINES.  IT ALSO CLEARS THE COARSE OPTICS FLAG BIT AND DISABLES THE OPTICS ERROR COUNTER.

# CALLING SEQUENCE-

#	TC	BANKCALL
#	CADR	MKRELEAS

# NORMAL EXIT MODE-
#	SWRETURN

# ALARM OR ABORT EXIT MODE- NONE

# OUTPUT-
#	1) BIT9 OPTMODES SET TO 0
#	2) OPTIND SET TO -1
#	3) 1ST WORD OF VAC AREA SET TO VAC ADDRESS TO SIGNIFY AVAILABILITY.
#	4) MARKSTAT CLEARED
#	5) BIT2 CHANNEL 12 SET TO 0

# ERASABLE INITIALIZATION- NONE

# DEBRIS-
#	A,MARKSTAT,BIT9,OPTMODES OPTIND,BIT2 CHANNEL 12

MKRELEAS	CAF	ZERO			# SHOW MARK SYSTEM NOW AVAILABLE
		XCH	MARKSTAT
		MASK	LOW9
		CCS	A
		INDEX	A
		TS	0
MKRLEES		INHINT
		CS	BIT9			# COARSE OPTICS RETURN FLAG.
		MASK	OPTMODES
		TS	OPTMODES

		CA	NEGONE
		TS	OPTIND			# KILL COARSE OPTICS

		CS	BIT2			# DISABLE OPTICS ERROR COUNTER
		EXTEND
		WAND	CHAN12

		RELINT
		TC	SWRETURN
# Page 225
# PROGRAM NAME - MARKRUPT					DATE- 5 APRIL 1967
# PROGRAM MODIFIED BY 258/278 PROGRAMMERS		       LOG SECTION SXTMARK
# MOD BY- R. MELANSON TO ADD DOCUMENTATION		 ASSEMBLY SUNDISK REV. 116

# FUNCTIONAL DESCRIPTION-
#	MARKRUPT STORES CDUS,OPTICS AND TIME AND TRANSFERS CONTROL TO THE MARKIT,MARK REJECT OR KEYCOM ROUTINES IF
#	BITS IN CHANNEL 16 ARE SET AS REQUIRED.

# CALLING SEQUENCE-
#	ROUTINE ENTERED VIA KEYRUPT2 WHEN MARK,MARK REJECT OR DSKY KEYS DEPRESSED BY THE OPERATOR.

# NORMAL EXIT MODE-
#	MARKIT, MKREJECT, OR POSTJUMP ROUTINES (MARK,MARK REJECT, OR DSKY CODE)

# ALARM OR ABORT EXIT MODE-
#	ALARM AND RESUME

# OUTPUT-
#	RUPTSTOR+5 = CDUT, RUPTSTOR+3 = CDUS, RUPTSTOR+2 = CDUY,
#	RUPTREG3 = CDUZ, RUPTSTOR+6 = CDUX, RUPTSTOR+1 AND SAMPTIME+1 =TIME1,
#	RUPTSTOR AND SAMPTIME = TIME2

# ERASABLE INITIALIZATION-
#	CDUT,CDUS,CDUY,CDUZ,CDUX,TIME2,TIME1,CHANNEL 16 BITS 6,7 OR 1-5

# DEBRIS-
#	A,QRUPT,RUPTREG3,SAMPTIME,SAMPTIME+1,RUPTSTOR TO RUPTSTOR+6 EXCEPT RUPTSTOR+4 (LOCATION 67)

MARKRUPT	TS	BANKRUPT		# STORE CDUS AND OPTICS NOW
		CA	CDUT
		TS	MKCDUT
		CA	CDUS
		TS	MKCDUS
		CA	CDUY
		TS	MKCDUY
		CA	CDUZ
		TS	MKCDUZ
		CA	CDUX
		TS	MKCDUX
		EXTEND
		DCA	TIME2			# GET TIME
		DXCH	MKT2T1
		EXTEND
		DCA	MKT2T1
		DXCH	SAMPTIME		# RUPT TIME FOR NOUN 65.

		XCH	Q
		TS	QRUPT

		CAF	BIT6			# SEE IF MARK OR MKREJECT
# Page 226
		EXTEND
		RAND	NAVKEYIN
		CCS	A
		TC	MARKIT			# ITS A MARK

		CAF	BIT7			# NOT A MARK, SEE IF MKREJECT
		EXTEND
		RAND	NAVKEYIN
		CCS	A
		TC	MKREJECT		# ITS A MARK REJECT

KEYCALL		CAF	OCT37			# NOT MARK OR MKREJECT, SEE IF KEYCODE
		EXTEND
		RAND	NAVKEYIN
		EXTEND
		BZF	+3			# IF NO INBITS
		TC	POSTJUMP
		CADR	KEYCOM			# IT,S A KEY CODE, NOT A MARK.

	+3	TC	ALARM			# ALARM IF NO INBITS
		OCT	113
		TC	RESUME

# Page 227
# PROGRAM NAME - MARKCONT				DATE- 19 SEPT 1967

# PROGRAM MODIFIED BY 258/278 PROGRAMMERS	       LOG SECTION SXTMARK
# MOD BY- R. MELANSON TO ADD DOCUMENTATION	 ASSEMBLY SUNDISK REV. 116

# FUNCTIONAL DESCRIPTION-
#	MARKCONT IS USED TO PERFORM A SPECIAL MARK FUNCTION FOR R21, TO EXECUTE A SPECIAL DISPLAY OF OPTICS AND TIME OR
#	 TO PERFORM A MARK OF THE STAR OR LAND SIGHTING BASED UPON FLASHING V-N.

# CALLING SEQUENCE-
#	FROM MARKDIF

# NORMAL EXIT MODE-
#	TASKOVER

# ALARM OR ABORT EXIT MODE-
#	ALARM AND TASKOVER

# OUTPUT-
#	1) FOR R21-
#	   EBANK=EBANK7
#	   MRKBUF1 TO MRKBUF1+6 = TIME2,TIME1,CDUY,OPTICX,CDUZ,OPTICSY,CDUX OF CURRENT R21 MARK FUNCTION.
#	   MRKBUF2 TO MRKBUF2+6 CONTAINS PREVIOUS R21 MARK VALUES.
#	2) FOR SPECIAL DISPLAY JOB-
#	   RUPTREG1 AND MRKBUF1 = CDUS,RUPTREG2 AND MRKBUF1 +1 = CDUT.
#	   RUPTREG3 AND MRKBUF1 +2 = TIME2,RUPTREG4 AND MRKBUF1 +3 = TIME1
#	3) FOR NORMAL MARKING-
#	   DECREMENT BITS14-12 OF MARKSTAT BY 1,
#	   BIT10 MARKSTAT SET TO 1,INCREMENT QPRET BY 7,
#	   STORE TIME2,TIME1,CDUY,CDUS,CDUZ,CDUT AND CDUX IN VAC+1 TO VAC+7

# ERASABLE INITIALIZATION-
#	1) FOR R21-
#	   BIT14 OF STATE+2 =1, MRKBUF1 TO MRKBUF1+6, ITEMP1, RUPTREG3,
#	   RUPTSTOR TO RUPTSTOR+6 EXCEPT RUPTSTOR+4
#	2) FOR SPECIAL DISPLAY JOB-
#	   BIT14 OF STATE+2 =0,MARKSTAT =+0,RUPTREG1,RUPTREG2,RUPTREG3
#	   RUPTREG4,RUPTSTOR,RUPTSTOR+1,RUPTSTOR+3,RUPTSTOR+5,
#	   BIT12 OF STATE+5 (V59 FLAG),MRKBUF1 THRU MRKBUF1+3
#	3) FOR NORMAL MARKING-
#	   BIT14 OF STATE+2 =0,MARKSTAE =VAC ADDRESS, A REG, ITEMP1, RUPTREG3,
#	   RUPTSTOR TO RUPTSTOR+6 EXCEPT RUPTSTOR+4.

# DEBRIS-
#	1) FOR R21-
#	   A,ITEMP1,MRKBUF1,MRKBUF2
#	2) FOR SPECIAL DISPLAY JOB-
#	   A,RUPTREG1,RUPTREG2,RUPTREG3,RUPTREG4,MPAC TO MPAC+3
#	3) FOR NORMAL MARKING-
#	   A,MARKSTAT,ITEMP1,QPRET,VAC+1 TO VAC+7 OF VAC AREA IN USE

# Page 228
MARKCONT	CAF	BIT14
		MASK	STATE	+2		# R21 MARK (SPECIAL MARKING FOR R21)
		EXTEND
		BZF	MARKET			# NOT SET THEREFORE REGULAR MARKING
MARKIT1		CAF	SIX			# SPECIAL FOR R21
		TC	GENTRAN			# TRANSFER MRKBUF1 TO MRKBUF2
		ADRES	MRKBUF1
		ADRES	MRKBUF2

		CAF	SIX			# TRANSFER CURRENT MARK DATA TO MARKBUF1
		TC	GENTRAN
		ADRES	MKT2T1
		ADRES	MRKBUF1

		TCF	TASKOVER

MARKET		CCS	MARKSTAT		# SEE IF MARKS CALLED FOR
		TC	MARK2			# COLLECT MARKS

		CAF	TWO			# IS MARKING SYSTEM IN USE (BIT2)
		MASK	EXTVBACT
		EXTEND
		BZF	MARKET3			# MARKING NOT CALLED FOR
		CAF	BIT12
		MASK	STATE	+5		# V59FLAG
		EXTEND
		BZF	MARKET3			# IF V59FLAG NOT SET-MARK UNCALLED FOR
		CAF	PRIO5			# CALIBRATION MARK (SET) FOR P23
		TC	NOVAC			# SPECIAL DISPLAY JOB
		EBANK=	MRKBUF1
		2CADR	MARKDISP

		CAF	SIX
		TC	GENTRAN			# TRANSFER MARK DATE TO MARKDOWN
		ADRES	MKT2T1
		ADRES	MARKDOWN
		CAF	SIX
		TC	GENTRAN			# TRANSFER MARK DATA TO MRKBUF1 FOR
		ADRES	MKT2T1			# SPECIAL DISPLAY OF SHAFT AND TRUNNION
		ADRES	MRKBUF1			# IF V59 ACTING
		TCF	TASKOVER
MARKET3		TC	ALARM
		OCT	122			# MARKING NOT CALLED FOR
		TCF	TASKOVER
114ALM		TC	ALARM			# MARK NOT WANTED
		OCT	114
		TCF	TASKOVER

# Page 229
# STORE MARK DATA IN MKVAC AND INCREMENT POINTER

MARK2		AD	74K			# SEE IF MARKS WANTED-REDUCE MARKS WANTED
		EXTEND
		BZMF	114ALM			# MARK NOT WANTED-ALARM
		TS	MARKSTAT
		COM
		MASK	BIT10			# SET BIT10 TO ENABLE REJECT
		ADS	MARKSTAT

		MASK	LOW9
		TS	ITEMP1
		INDEX	A
		XCH	QPRET			# PICK UP MARK SLOT-POINTER
		TS	ITEMP2			# SAVE CURRENT POINTER
		AD	SEVEN			# INCREMENT POINTER
		INDEX	ITEMP1
		TS	QPRET			# STORE ADVANCED POINTER

VACSTOR		EXTEND
		DCA	MKT2T1
		INDEX	ITEMP2
		DXCH	0
		CA	MKCDUY
		INDEX	ITEMP2
		TS	2
		CA	MKCDUS
		INDEX	ITEMP2
		TS	3
		CA	MKCDUZ
		INDEX	ITEMP2
		TS	4
		CA	MKCDUT
		INDEX	ITEMP2
		TS	5
		CA	MKCDUX
		INDEX	ITEMP2
		TS	6

		CAF	PRIO34			# IF ALL MARKS MADE FLASH VB50
		MASK	MARKSTAT
		EXTEND
		BZF	+2
		TCF	TASKOVER
		CAF	PRIO32
		TC	NOVAC
		EBANK=	MARKSTAT
		2CADR	MKVB50

		TCF	TASKOVER

# Page 230
# PROGRAM NAME - MKREJECT					DATE- 5 APRIL 1967
# PROGRAM MODIFIED BY 258/276 PROGRAMMERS		       LOG SECTION SXTMARK
# MOD BY- R. MELANSON TO ADD DOCUMENTATION		 ASSEMBLY SUNDISK REV. 116

# FUNCTIONAL DESCRIPTION-
#	ROUTINE ALLOWS OPEATOR TO REJECT MARK MADE PRIOR TO ACCEPTANCE AND ALLOWS A NEW MARK TO BE MADE BY ASTRONAUT

# CALLING SEQUENCE-
#	FROM MARKRUPT IF BIT7 OF CHANNEL 16 IS 1.

# NORMAL EXIT MODE-
#	RESUME

# ALARM OR ABORT EXIT MODE-
#	ALARM AND RESUME

# OUTPUT-
#	1) FOR R21-
#	  MRKRUP1 SET TO -1
#	2) FOR NORMAL MARKING-
#	   BIT10 MARKSTAT =0,INCREMENT NO. MARKS BY 1,DECREMENT QPRET BY 7

# ERASABLE INITIALIZATION-
#	1) FOR R21-
#	   BIT14 OF STATE+2 SET TO 1
#	2) FOR NORMAL MARKING-
#	   BIT14 OF STATE+2 SET TO 0, MARKSTAT,QPRET

# DEBRIS-
#	1) FOR R21-
#	   A,MARKSTAT,EBANK
#	2) FOR NORMAL MARKING-
#	   A,MARKSTAT,ITEMP1,QPRET

MKREJECT	CAF	BIT14
		MASK	STATE	+2		# R21 MARK (SPECIAL MARKING FOR R21)
		EXTEND
		BZF	MRKREJCT		# NOT SET THEREFORE REGULAR REJECT
		CA	NEGONE			# -1 (FOR R22)
		TS	MRKBUF1			# -0 IN TIME IS FLAG TO R22 SIGNIFYING A
		TC	RESUME			# REJECTED MARK
MRKREJCT	CCS	MARKSTAT		# SEE IF MARKS BEING ACCEPTED
		TC	REJECT2
		TC	ALARM			# MARKS NOT BEING ACCEPTED
		OCT	112
		TC	RESUME

REJECT2		CS	BIT10			# SEE IF MARK HAD BEEN MADE SINCE LAST
		MASK	MARKSTAT		# REJECT, AND SET BIT10 TO ZERO TO
		XCH	MARKSTAT		# SHOW MARK REJECT
# Page 231
		MASK	BIT10
		CCS	A
		TC	REJECT3

		TC	ALARM			# DONT ACCEPT TWO REJECTS TOGETHER
		OCT	110
		TC	RESUME

REJECT3		CAF	LOW9			# DECREMENT POINTER TO REJECT MARK
		MASK	MARKSTAT
		TS	ITEMP1
		CS	SEVEN
		INDEX	ITEMP1
		ADS	QPRET			# NEW POINTER

		CAF	BIT12			# INCREMENT MARKS WANTED AND IF FIELD
		AD	MARKSTAT		# IS NOW NON-ZERO, CHANGE TO VB51 TO
		XCH	MARKSTAT		# INDICATE MORE MARKS WANTED
		MASK	PRIO34			# INDICATE MORE MARKS WANTED
		CCS	A
		TC	RESUME
		CAF	PRIO32
		TC	NOVAC
		EBANK=	MARKSTAT
		2CADR	MKVB51

		TC	RESUME

# Page 232
# PROGRAM DESCRIPTION MKVB51 AND MKVB50

# AUTHOR-BARNERT DATE-2-15-67 MOD-0
# PURPOSE	FLASH V51N70,V51N43, OR V51 TO REQUEST MARKING,
#		AND V50N25 R1=16 TO REQUEST TERMINATE MARKING.

# CALLING SEQUENCE	AS JOB WITHIN SXTMARK

# EXIT TO ENDMARK UPON RECEIPT OF V33, V34 CAUSES GOTOP00H, ENTER
#		RECYCLES THE DISPLAY

# NOTE- SXTMARK AUTOMATICALLY CHANGES FROM CALLING MKVB51 TO MKVB50 WHEN
#		SUFFICIENT MARKS HAVE BEEN MADE, AND THE REVERSE WHEN A MARK
#		REJECT REDUCES THE NUMBER MADE BELOW THAT REQUIRED

# SUBROUTINES CALLED- BANKCALL, GOMARK2,GOODEND,ENDMARK,WAITLIST

# ALARM OR ABORT MODES - NONE

# ERASABLE USED-VERBREG,MARKSTAT,QPRET,DSPTEM1

# OUTPUT MARKSTAT=VAC ADDRESS

# 	 QPRET=	NO.MARKS
MKVB51		TC	BANKCALL		# CLEAR DISPLAY FOR MARK VERB
		CADR	KLEENEX
		CAF	VB51			# DISPLAY MARK VB51
		TC	BANKCALL
		CADR	GOMARK4
		TCF	TERMSXT			# VB34-TERMINATE
		TCF	ENTANSWR		# V33-PROCEED-MARKING DONE
		TCF	MKVB5X			# ENTER-RECYCLE TO INITIAL MARK DISPLAY

TERMSXT		TC	CLEARMRK		# CLEAR MARK ACTIVITY.

		TC	CHECKMM
		MM	03
		TCF	+2
		TC	TERMP03
		TC	POSTJUMP
		CADR	TERM52

TERMP03		TC	UPFLAG
		ADRES	TRM03FLG
ENTANSWR	CAF	LOW9			# PUT VAC ADR IN MARKSTAT AND NO. OF
		MASK	MARKSTAT		# MARKS MADE IN QPRET BEFORE LEAVING
		TS	MARKSTAT		# SXTMARK
		COM
		INDEX	MARKSTAT
		AD	QPRET
# Page 233
		EXTEND
		BZMF	JAMIT			# NO MARKS MADE, SHOW IT IN QPRET, R53
		EXTEND				#	WILL PICK IT UP AND RECYCLE
		MP	BIT12			# THIS PUTS NUMBER MARKS-1 IN A
		AD	ONE
JAMIT		INDEX	MARKSTAT		# STORE NO OF MARKS MADE
		TS	QPRET
		INHINT				# SERVICE OPTSTALL INTERFACE WITH
		CAF	FIVE
		TC	WAITLIST
		EBANK=	MARKSTAT
		2CADR	ENDMARKS

		TC	ENDMARK			# KNOCKS DOWN MARKING FLAG + DOES ENDOFJOB

ENDMARKS	CAF	ONE
		TC	IBNKCALL
		CADR	GOODEND
MKVB5X		CAF	PRIO34
		MASK	MARKSTAT		# RE-DISPLAY VB51 IF MORE MARKS WANTED
		CCS	A			# AND VB50 IF ALL IN
		TCF	MKVB51
MKVB50		CAF	R1D1			# OCT 16
		TS	DSPTEM1
		CAF	V50N25
		TCF	MKVB51	+3

V50N25		VN	5025
VB51		VN	5100
OCT37		=	LOW5

# PROGRAM NAME - MARKIT				DATE- 19 SEPT 1967

# CALLING SEQUENCE
#	FROM MARKRUPT IF CHAN 16 BIT 6 = 1

# EXIT
#	RESUME

# INPUT
#	CDUCHKWD.  ALSO ALL INITIALIZATION FOR MARKCONT

# OUTPUT
#	MKT2T1,MKCDUX,MKCDUY,MKCDUZ,MKCDUS,MKCDUT

# ALARM EXIT
#	NONE

MARKIT		CCS	CDUCHKWD
		TCF	+3			# DELAY OF CDUCHKWD CS IF PNZ
# Page 234
		TCF	+2
		CAF	ZERO
		AD	ONE			# 10 MS IF NO CHECK
		TC	WAITLIST
		EBANK=	MRKBUF1
		2CADR	MARKDIF

		TCF	RESUME

		SETLOC	SXTMARK1
		BANK

		COUNT	20/SXTMK

# PROGRAM NAME - MARKDIF			DATE- 19 SEPT 1967

# CALLING SEQUENCE
#	WAITLIST FROM MARKIT

# EXIT
#	TASKOVER TO IBNKCALL TO MARKCONT

# INPUT
# 	OUTPUT FROM MARKIT, INPUT TO MARKCONT, CDUCHKWD

# OUTPUT
#	RUPTSTOR - RUPTSTOR+3,RUPTREG3,RUPTSTOR+5 - RUPTSTOR+6

# ALARM EXIT
#	ALARM AND TASKOVER

MARKDIF		CA	CDUCHKWD		# IF DELAY CHECK IS ZERO OR NEG,ACP MARK
		EXTEND
		BZMF	MKACPT
		CS	BIT1
		TS	MKNDX			# SET INDEX -1
		CA	MKCDUX
		TC	DIFCHK			# SEE IF VEHICLE RATE TO MUCH AT MARK
		CA	MKCDUY
		TC	DIFCHK
		CA	MKCDUZ
		TC	DIFCHK

MKACPT		TC	IBNKCALL
		CADR	MARKCONT		# MARK DATA OK, WHAT DO WE DO WITH IT

DIFCHK		INCR	MKNDX			# INCREMENT INDEX

		EXTEND
		INDEX	MKNDX
# Page 235
		MSU	CDUX			# GET MARK(ICDU) - CURRENT(ICDU)
		CCS	A
		TCF	+4
		TC	Q
		TCF	+2
		TC	Q
		AD	NEG2			# SEE IF DIFFERENCE GREATER THAN 3 BITS
		EXTEND
		BZMF	-3			# NOT GREATER

		TC	ALARM			# COUPLED WITH PROGRAM ALARM
		OCT	00121

		TCF	TASKOVER		# DO NOT ACCEPT