### FILE="Main.annotation"
## Copyright:	Public domain.
## Filename:	SXTMARK.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:	2011-01-13 JL	Adapted from corresponding Colossus 249 file.
##		2016-12-30 RSB	Proofed comment text using octopus/ProoferComments,
##				and corrected errors found.

## Page 215

# 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 EXECUTIONOF 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 216
		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		# SHOW 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 217

# PROGRAM NAME - MKRELEAS				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-
#    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
		CCS	A
		INDEX	A
		TS	0
MKRLEES		INHINT
		CS	BIT9		# COARSE OPTICS RETURN FLAG.
		MASK	OPTMODES
		TS	OPTMODES
		
		CA	NEGONE
		TS	OPTIND		# KILL COARS OPTICS
		
		CS	BIT2		# DISABLE OPTICS ERROR COUNTER
		EXTEND
		WAND	CHAN12
		
		RELINT
		TC	SWRETURN

## Page 218

# 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 219
		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 220

# 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 A 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, MARKSTAT =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 221

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	SIX
		TC	GENTRAN		# TRANSFER MARK DATA TO MARKDOWN
		ADRES	MKT2T1
		ADRES	MARKDOWN
		
		CAF	SIX
		TC	GENTRAN		# TRANSFER MARK DATA TO MRKBUF1 FOR
		ADRES	MKT2T1		# SPECIAL DISPLAY OF SHAFT AND TRUNION
		ADRES	MRKBUF1		# IF V59 ACTING
		
		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
		
		TCF	TASKOVER
MARKET3		TC	ALARM
		OCT	122		# MARKING NOT CALLED FOR
		TCF	TASKOVER
114ALM		TC	ALARM		# MARK NOT WANTED
		OCT	114
		TCF	TASKOVER
		
## Page 222
#    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 223

# PROGRAM NAME - MKREJECT			        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-
#    ROUTINE ALLOWS OPERATOR 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-
#      MRKBUF1 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 224
		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 225

# 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 GOTOPOOH, 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 226
		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 227
		TCF	+2
		CAF	ZERO
		AD	ONE		# 10 MS IF NO CHECK
		TC	WAITLIST
		EBANK=	MRKBUF1
		2CADR	MARKDIF
		TCF	RESUME
		
		SETLOC	SXTMARK1
		BANK
		
		COUNT	10/SXTMK
		
# PROGRAM NAME - MARKDIF				DATE- 19 SEPT 1967
#
# CALLING SEQUENCE
#    WAITLIST FROM MARKIT
#
# EXIT
#    TASKOVER OT 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 228
		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