AGC_BLOCK_TWO_SELF_CHECK.s

# Copyright:	Public domain.
# Filename:	AGC_BLOCK_TWO_SELF_CHECK.agc
# Purpose: 	Part of the source code for Luminary 1A build 099.
#		It is part of the source code for the Lunar Module's (LM)
#		Apollo Guidance Computer (AGC), for Apollo 11.
# Assembler:	yaYUL
# Contact:	Onno Hommes <ohommes@cmu.edu>.
# Website:	www.ibiblio.org/apollo.
# Pages:	1284-1293
# Mod history:	2009-05-27 OH	Transcribed from page images.
#
# 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 001 of AGC program LMY99 by NASA 2021112-61
#	16:27 JULY 14, 1969 

# Page 1284
# PROGRAM DESCRIPTION				DATE:  20 DECEMBER 1967
# PROGRAM NAME -- SELF-CHECK			LOG SECTION:  AGC BLOCK TWO SELF-CHECK
# MOD NO -- 1					ASSEMBLY SUBROUTINE UTILITYM REV 25
# MOD BY -- GAUNTT
#
# FUNCTIONAL DESCRIPTION
#	PROGRAM HAS TWO MAIN PARTS.  THE FIRST IS SELF-CHECK WHICH RUNS AS A ZERO PRIORITY JOB WITH NO CORE SET, AS
#	PART OF THE BACK-UP IDLE LOOP.  THE SECOND IS SHOW-BANKSUM WHICH RUNS AS A REGULAR EXECUTIVE JOB WITH ITS OWN
# 	STARTING VERB.
#
#	THE PURPOSE OF SELF-CHECK IS TO CHECK OUT VARIOUS PARTS OF THE COMPUTER AS OUTLINED BELOW IN THE OPTIONS.
#
#	THE PURPOSE OF SHOW-BANKSUM IS TO DISPLAY THE SUM OF EACH BANK, ONE AT A TIME.
#
#	IN ALL THERE ARE 7 POSSIBLE OPTIONS IN THIS BLOCK II VERSION OF SELF-CHECK.  MORE DETAIL DESCRIPTION MAY BE
#	FOUND IN E-2065 BLOCK II AGC SELF-CHECK AND SHOW BANKSUM BY EDWIN D. SMALLY DECEMBER 1966, AND ADDENDA 2 AND 3.
#
#	THE DIFFERENT OPTIONS ARE CONTROLLED BY PUTTING DIFFERENT NUMBERS IN THE SMODE REGISTER (NOUN 27).  BELOW IS
# 	A DESCRIPTION OF WHAT PARTS OF THE COMPUTER THAT ARE CHECKED BY THE OPTIONS, AND THE CORRESPONDING NUMBER, IN
#	OCTAL, TO LOAD INTO SMODE.
#		+-4		ERASABLE MEMORY
#		+-5		FIXED MEMORY
#		+-1,2,3,6,7,10	EVERYTHING IN OPTIONS 4 AND 5.
#		-0		SAME AS +-10 UNTIL AN ERROR IS DETECTED.
#		+0		NO CHECK, PUTS COMPUTER INTO THE BACKUP IDLE LOOP.
#
# WARNINGS
#	USE OF E MEMORY RESERVED FOR SELF-CHECK (EVEN IN IDLE LOOP) AS TEMP STORAGE BY OTHER PROGRAMS IS DANGEROUS.
#	SMODE SET GREATER THAN OCT 10 PUTS COMPUTER INTO BACKUP IDLE LOOP.
#
# CALLING SEQUENCE
#	TO CALL SELF-CHECK KEY IN
#		V 21 N 27 E	OPTION NUMBER E
#	TO CALL SHOW-BANKSUM KEY IN
#		V 91 E		DISPLAYS FIRST BANK
#		V 33 E		PROCEED, DISPLAYS NEXT BANK
#
# EXIT MODES, NORMAL AND ALARM
#	SELF-CHECK NORMALLY CONTINUES INDEFINITELY UNLESS THERE IS AN ERROR DETECTED.  IF SO + OPTION NUMBERS PUT
#	COMPUTER INTO BACKUP IDLE LOOP, - OPTIONS NUMBERS RESTART THE OPTION.
#
#	THE -0 OPTION PROCEEDS FROM THE LINE FOLLOWING THE LINE WHERE THE ERROR WAS DETECTED.
#
#	SHOW-BANKSUM PROCEEDS UNTIL A TERMINATE IS KEYED IN (V 34 E).  THE COMPUTER IS PUT INTO THE BACKUP IDLE LOOP.
#
# OUTPUT
# Page 1285
#	SELF-CHECK UPON DETECTING AN ERROR LOADS THE SELF-CHECK ALARM CONSTANT (01102) INTO THE FAILREG SET AND
#	TURNS ON THE ALARM LIGHT.  THE OPERATOR MAY THEN DISPLAY THE THREE FAILREGS BY KEYING IN V 05 N 09 E.  FOR FURTHER
# 	INFORMATION HE MAY KEY IN V 05 N 08 E, THE DSKY DISPLAY IN R1 WILL BE ADDRESS+1 OF WHERE THE ERROR WAS DETECTED,
#	IN R2 THE BBCON OF SELF-CHECK, AND IN R3 THE TOTAL NUMBER OF ERRORS DETECTED BY SELF-CHECK SINCE THE LAST MAN
#	INITIATED FRESH START (SLAP1).
#
#	SHOW-BANKSUM STARTING WTIH BANK 0 DISPLAYS IN R1 THE BANK SUM (A +-NUMBER EQUAL TO THE BANK NUMBER), IN R2
#	THE BANK NUMBER, AND IN R3 THE BUGGER WORD.
#
# ERASABLE INITIALIZATION REQUIRED
#	ACCOMPLISHED BY FRESH START
#		SMODE SET TO +0
#
# DEBRIS
#	ALL EXITS FROM THE CHECK OF ERASABLE (ERASCHK) RESTORE ORIGINAL CONTENTS TO REGISTERS UNDER CHECK.
#	EXCEPTION IS A RESTART.  RESTART THAT OCCURS DURING ERASCHK RESTORES ERASABLE, UNLESS THERE IS EVIDENCE TO DOUBT
#	E MEMORY, IN WHICH CASE PROGRAM THEN DOES A FRESH START (DOFSTART).

		BANK	25
		SETLOC	SELFCHEC
		BANK

		COUNT*	$$/SELF
SBIT1		EQUALS	BIT1
SBIT2		EQUALS	BIT2
SBIT3		EQUALS	BIT3
SBIT4		EQUALS	BIT4
SBIT5		EQUALS	BIT5
SBIT6		EQUALS	BIT6
SBIT7		EQUALS	BIT7
SBIT8		EQUALS	BIT8
SBIT9		EQUALS	BIT9
SBIT10		EQUALS	BIT10
SBIT11		EQUALS	BIT11
SBIT12		EQUALS	BIT12
SBIT13		EQUALS	BIT13
SBIT14		EQUALS	BIT14
SBIT15		EQUALS	BIT15

S+ZERO		EQUALS	ZERO
S+1		EQUALS	BIT1
S+2		EQUALS	BIT2
S+3		EQUALS	THREE
S+4		EQUALS	FOUR
S+5		EQUALS	FIVE
S+6		EQUALS	SIX
# Page 1286
S+7		EQUALS	SEVEN
S8BITS		EQUALS	LOW8		# 00377
CNTRCON		=	OCT50		# USED IN CNTRCHK
ERASCON1	OCTAL	00061		# USED IN ERASCHK
ERASCON2	OCTAL	01373		# USED IN ERASCHK
ERASCON6	=	OCT1400		# USED IN ERASCHK
ERASCON3	OCTAL	01461		# USED IN ERASCHK
ERASCON4	OCTAL	01773		# USED IN ERASCHK
S10BITS		EQUALS	LOW10		# 01777, USED IN ERASCHK
SBNK03		EQUALS	PRIO6		# 06000, USED IN ROPECHK
-MAXADRS	=	HI5		# FOR ROPECHK
SIXTY		OCTAL	00060
SUPRCON		OCTAL	60017		# USED IN ROPECHK
S13BITS		OCTAL	17777
CONC+S1		OCTAL	25252		# USED IN CYCLSHFT
CONC+S2		OCTAL	52400		# USED IN CYCLSHFT
ERASCON5	OCTAL	76777
S-7		=	OCT77770
S-4		EQUALS	NEG4
S-3		EQUALS	NEG3
S-2		EQUALS	NEG2
S-1		EQUALS	NEGONE
S-ZERO		EQUALS	NEG0

		EBANK=	LST1
ADRS1		ADRES	SKEEP1
SELFADRS	ADRES	SELFCHK		# SELFCHK RETURN ADDRESS.  SHOULD BE PUT
					# IN SELFRET WHEN GOING FROM SELFCHK TO
					# SHOWSUM AND PUT IN SKEEP1 WHEN GOING
					# FROM SHOWSUM TO SELF-CHECK.

PRERRORS	CA	ERESTORE	# IS IT NECESSARY TO RESTORE ERASABLE
		EXTEND
		BZF	ERRORS		# NO
		EXTEND
		DCA	SKEEP5
		INDEX	SKEEP7
		DXCH	0000		# RESTORE THE TWO ERASABLE REGISTERS
		CA	S+ZERO
		TS	ERESTORE
ERRORS		INHINT
		CA	Q
		TS	SFAIL		# SAVE Q FOR FAILURE LOCATION
		TS	ALMCADR		# FOR DISPLAY WITH BBANK AND ERCOUNT
		INCR	ERCOUNT		# KEEP TRACK OF NUMBER OF MALFUNCTIONS.
TCALARM2	TC	ALARM2
		OCT	01102		# SELF-CHECK MALFUNCTION INDICATOR
		CCS	SMODE
SIDLOOP		CA	S+ZERO
		TS	SMODE
# Page 1287
		TC	SELFCHK		# GO TO IDLE LOOP
		TC	SFAIL		# CONTINUE WITH SELF-CHECK

-1CHK		CCS	A
		TCF	PRERRORS
		TCF	PRERRORS
		CCS	A
		TCF	PRERRORS
		TC	Q

SMODECHK	EXTEND
		QXCH	SKEEP1
		TC	CHECKNJ		# CHECK FOR NEW JOB
		CCS	SMODE
		TC	SOPTIONS
		TC	SMODECHK +2	# TO BACKUP IDLE LOOP
		TC	SOPTIONS
		INCR	SCOUNT
		TC	SKEEP1		# CONTINUE WITH SELF-CHECK

SOPTIONS	AD	S-7
		EXTEND
		BZMF	+2		# FOR OPTIONS BELOW NINE.
BNKOPTN		TC	SIDLOOP		# ILLEGAL OPTION.  GO TO IDLE LOOP.
		INCR	SCOUNT		# FOR OPTIONS BELOW NINE.
		AD	S+7

		INDEX	A
		TC	SOPTION1
SOPTION1	TC	SKEEP1		# WAS TC+TCF
SOPTION2	TC	SKEEP1		# WAS IN:OUT1
SOPTION3	TC	SKEEP1
SOPTION4	TC	ERASCHK
SOPTION5	TC	ROPECHK
SOPTION6	TC	SKEEP1
SOPTION7	TC	SKEEP1
SOPTON10	TC	SKEEP1		# CONTINUE WITH SELF-CHECK

CHECKNJ		EXTEND
		QXCH	SELFRET		# SAVE RETURN ADDRESS WHILE TESTING NEWJOB
		TC	POSTJUMP	# TO SEE IF ANY JOBS HAVE BECOME ACTIVE.
		CADR	ADVAN

SELFCHK		TC	SMODECHK	# ** CHARLEY, COME IN HERE

# SKEEP7 HOLDS LOWEST OF TWO ADDRESSES BEING CHECKED.
# SKEEP6 HOLDS B(X+1).
# SKEEP5 HOLDS B(X).
# SKEEP4 HOLDS C(EBANK) DURING ERASLOOP AND CHECKNJ
# SKEEP3 HOLDS LAST ADDRESS BEING CHECKED (HIGHEST ADDRESS).
# Page 1288
# SKEEP2 CONTROLS CHECKING OF NON-SWITCHABLE ERASABLE MEMORY WITH BANK NUMBERS IN EB.
#
# ERASCHK TAKES APPROXIMATELY 7 SECONDS.

ERASCHK		CA	S+1
		TS	SKEEP2
0EBANK		CA	S+ZERO
		TS	EBANK
		CA	ERASCON3	# 01461
		TS	SKEEP7		# STARTING ADDRESS
		CA	S10BITS		# 01777
		TS	SKEEP3		# LAST ADDRESS CHECKED
		TC	ERASLOOP

E134567B	CA	ERASCON6	# 01400
		TS	SKEEP7		# STARTING ADDRESS
		CA	S10BITS		# 01777
		TS	SKEEP3		# LAST ADDRESS CHECKED
		TC	ERASLOOP

2EBANK		CA	ERASCON6	# 01400
		TS	SKEEP7		# STARTING ADDRESS
		CA	ERASCON4	# 01773
		TS	SKEEP3		# LAST ADDRESS CHECKED
		TC	ERASLOOP

NOEBANK		TS	SKEEP2		# +0
		CA	ERASCON1	# 00061
		TS	SKEEP7		# STARTING ADDRESS
		CA	ERASCON2	# 01373
		TS	SKEEP3		# LAST ADDRESS CHECKED

ERASLOOP	INHINT
		CA	EBANK		# STORES C(EBANK)
		TS	SKEEP4
		EXTEND
		NDX	SKEEP7
		DCA	0000
		DXCH	SKEEP5		# STORES C(X) AND C(X+1) IN SKEEP6 AND 5.
		CA	SKEEP7
		TS	ERESTORE	# IF RESTART, RESTORE C(X) AND C(X+1)
		TS	L
		INCR	L
		NDX	A
		DXCH	0000		# PUTS OWN ADDRESS IN X AND X +1
		NDX	SKEEP7
		CS	0001		# CS X+1
		NDX	SKEEP7
		AD	0000		# AD X
		TC	-1CHK
		CA	ERESTORE	# HAS ERASABLE BEEN RESTORED
		EXTEND
# Page 1289
		BZF	ELOOPFIN	# YES, EXIT ERASLOOP.
		EXTEND
		NDX	SKEEP7
		DCS	0000		# COMPLEMENT OF ADDRESS OF X AND X+1
		NDX	SKEEP7
		DXCH	0000		# PUT COMPLEMENT OF ADDRESS OF X AND X+1
		NDX	SKEEP7
		CS	0000		# CS X
		NDX	SKEEP7
		AD	0001		# AD X+1
		TC	-1CHK
		CA	ERESTORE	# HAS ERASABLE BEEN RESTORED
		EXTEND
		BZF	ELOOPFIN	# YES, EXIT ERASLOOP.
		EXTEND
		DCA	SKEEP5
		NDX	SKEEP7
		DXCH	0000		# PUT B(X) AND B(X+1) BACK INTO X AND X+1
		CA	S+ZERO
		TS	ERESTORE	# IF RESTART, DO NOT RESTORE C(X), C(X+1)
ELOOPFIN	RELINT
		TC	CHECKNJ		# CHECK FOR NEW JOB
		CA	SKEEP4		# REPLACES B(EBANK)
		TS	EBANK
		INCR	SKEEP7
		CS	SKEEP7
		AD	SKEEP3
		EXTEND
		BZF	+2
		TC	ERASLOOP	# GO TO NEXT ADDRESS IN SAME BANK
		CCS	SKEEP2
		TC	NOEBANK
		INCR	SKEEP2		# PUT +1 IN SKEEP2.
		CA	EBANK
		AD	SBIT9
		TS	EBANK
		AD	ERASCON5	# 76777, CHECK FOR BANK E2
		EXTEND
		BZF	2EBANK
		CCS	EBANK
		TC	E134567B	# GO TO EBANKS 1,3,4,5,6, AND 7
		CA	ERASCON6	# END OF ERASCHK
		TS	EBANK

# CNTRCHK PERFORMS A CS OF ALL REGISTERS FROM OCT. 60 THROUGH OCT. 10.
# INCLUDED ARE ALL COUNTERS, T6-1, CYCLE AND SHIFT, AND ALL RUPT REGISTERS

CNTRCHK		CA	CNTRCON		# 00050
CNTRLOOP	TS	SKEEP2
		AD	SBIT4		# +10 OCTAL
		INDEX	A
		CS	0000
# Page 1290
		CCS	SKEEP2
		TC	CNTRLOOP

# CYCLSHFT CHECKS THE CYCLE AND SHIFT REGISTERS

CYCLSHFT	CA	CONC+S1		# 25252
		TS	CYR		# C(CYR) = 12525
		TS	CYL		# C(CYL) = 52524
		TS	SR		# C(SR) = 12525
		TS	EDOP		# C(EDOP) = 00125
		AD	CYR		# 37777		C(CYR) = 45252
		AD	CYL		# 00-12524	C(CYL) = 25251
		AD	SR		# 00-25251	C(SR) = 05252
		AD	EDOP		# 00-25376	C(EDOP) = +0
		AD	CONC+S2		# C(CONC+S2) = 52400
		TC	-1CHK
		AD	CYR		# 45252
		AD	CYL		# 72523
		AD	SR		# 77775
		AD	EDOP		# 77775
		AD	S+1		# 77776
		TC	-1CHK

		INCR	SCOUNT +1
		TC	SMODECHK

# SKEEP1 HOLDS SUM
# SKEEP2 HOLDS PRESENT CONTENTS OF ADDRESS IN ROPECHK AND SHOWSUM ROUTINES
# SKEEP2 HOLDS BANK NUMBER IN LOW ORDER BITS DURING SHOWSUM DISPLAY
# SKEEP3 HOLDS PRESENT ADDRESS (00000 TO 01777 IN COMMON FIXED BANKS)
#			       (04000 TO 07777 IN FXFX BANKS)
# SKEEP3 HOLDS BUGGER WORD DURING SHOWSUM DISPLAY
# SKEEP4 HOLDS BANK NUMBER AND SUPER BANK NUMBER
# SKEEP5 COUNTS 2 SUCCESSIVE TC SELF WORDS
# SKEEP6 CONTROLS ROPECHK OR SHOWSUM OPTION
# SKEEP7 CONTROLS WHEN ROUTINE IS IN COMMON FIXED OR FIXED FIXED BANKS

ROPECHK		CA	S-ZERO		# *
		TS	SKEEP6		# * -0 FOR ROPECHK
STSHOSUM	CA	S+ZERO		# * SHOULD BE ROPECHK

		TS	SKEEP4		# BANK NUMBER
		CA	S+1
COMMFX		TS	SKEEP7
		CA	S+ZERO
		TS	SKEEP1
		TS	SKEEP3
		CA	S+1
		TS	SKEEP5		# COUNTS DOWN 2 TC SELF WORDS
COMADRS		CA	SKEEP4
		TS	L		# TO SET SUPER BANK
		MASK	HI5
# Page 1291
		AD	SKEEP3
		TC	SUPDACAL	# SUPER DATA CALL
		TC	ADSUM
		AD	SBIT11		# 02000
		TC	ADRSCHK

FXFX		CS	A
		TS	SKEEP7
		EXTEND
		BZF	+3
		CA	SBIT12		# 04000, STARTING ADDRESS OF BANK 02
		TC	+2
		CA	SBNK03		# 06000, STARTING ADDRESS OF BANK 03
		TS	SKEEP3
		CA	S+ZERO
		TS	SKEEP1
		CA	S+1
		TS	SKEEP5		# COUNTS DOWN 2 TC SELF WORDS
FXADRS		INDEX	SKEEP3
		CA	0000
		TC	ADSUM
		TC	ADRSCHK

ADSUM		TS	SKEEP2
		AD	SKEEP1
		TS	SKEEP1
		CAF	S+ZERO
		AD	SKEEP1
		TS	SKEEP1
		CS	SKEEP2
		AD	SKEEP3
		TC	Q

ADRSCHK		LXCH	A
		CA	SKEEP3
		MASK	LOW10		# RELATIVE ADDRESS
		AD	-MAXADRS	# SUBTRACT MAX RELATIVE ADDRESS = 1777.
		EXTEND
		BZF	SOPTION		# CHECKSUM FINISHED IF LAST ADDRESS.
		CCS	SKEEP5		# IS CHECKSUM FINISHED
		TC	+3		# NO
		TC	+2		# NO
		TC	SOPTION		# GO TO ROPECHK SHOWSUM OPTION
		CCS	L		# -0 MEANS A TC SELF WORD.
		TC	CONTINU
		TC	CONTINU
		TC	CONTINU
		CCS	SKEEP5
		TC	CONTINU +1
		CA	S-1
# Page 1292
		TC	CONTINU +1	# AD IN THE BUGGER WORD
CONTINU		CA	S+1		# MAKE SURE TWO CONSECUTIVE TC SELF WORDS
		TS	SKEEP5
		CCS	SKEEP6		# *
		CCS	NEWJOB		# * +1, SHOWSUM
		TC	CHANG1		# *
		TC	+2		# *
		TC	CHECKNJ		# -0 IN SKEEP6 FOR ROPECHK

ADRS+1		INCR	SKEEP3
		CCS	SKEEP7
		TC	COMADRS
		TC	COMADRS
		TC	FXADRS
		TC	FXADRS

NXTBNK		CS	SKEEP4
		AD	LSTBNKCH	# LAST BANK TO BE CHECKED
		EXTEND
		BZF	ENDSUMS		# END OF SUMMING OF BANKS.
		CA	SKEEP4
		AD	SBIT11
		TS	SKEEP4		# 37 TO 40 INCRMTS SKEEP4 BY END RND CARRY
		TC	CHKSUPR
17TO20		CA	SBIT15
		ADS	SKEEP4		# SET FOR BANK 20
		TC	GONXTBNK
CHKSUPR		MASK	HI5
		EXTEND
		BZF	NXTSUPR		# INCREMENT SUPER BANK
27TO30		AD	S13BITS
		EXTEND
		BZF	+2		# BANK SET FOR 30
		TC	GONXTBNK
		CA	SIXTY		# FIRST SUPER BANK
		ADS	SKEEP4
		TC	GONXTBNK
NXTSUPR		AD	SUPRCON		# SET BNK 30 + INCR SUPR BNK AND CANCEL
		ADS	SKEEP4		# ERC BIT OF TEH 37 TO 40 ADVANCE.
GONXTBNK	CCS	SKEEP7
		TC	COMMFX
		CA	S+1
		TC	FXFX
		CA	SBIT7		# HAS TO BE LARGER THAN NO OF FXSW BANKS.
		TC	COMMFX

SOPTION		CA	SKEEP4
		MASK	HI5		# = BANK BITS
		TC	LEFT5
		TS	L		# BANK NUMBER BEFORE SUPER BANK
# Page 1293
		CA	SKEEP4
		MASK	S8BITS		# = SUPER BANK BITS
		EXTEND
		BZF	SOPT		# BEFORE SUPER BANK
		TS	SR		# SUPER BANK NECESSARY
		CA	L
		MASK	SEVEN
		AD	SR
		TS	L		# BANK NUMBER WITH SUPER BANK
SOPT		CA	SKEEP6		# *
		EXTEND			# *
		BZF	+2		# * ON -0 CONTINUE WITH ROPE CHECK.
		TC	SDISPLAY	# * ON +1 GO TO DISPLAY OF SUM.
		CCS	SKEEP1		# FORCE SUM TO ABSOLUTE VALUE.
		TC	+2
		TC	+2
		AD	S+1
		TS	SKEEP1
BNKCHK		CS	L		# = - BANK NUMBER
		AD	SKEEP1
		AD	S-1
		TC	-1CHK		# CHECK SUM
		TC	NXTBNK

		EBANK=	NEWJOB
LSTBNKCH	BBCON*			# * CONSTANT, LAST BANK.