	PAGE	62
	TITLE		'IMSAI SCS-1 Rev. 2 06 Oct. 1976'
;
TTS	EQU	03H
TTI	EQU	02H
TTO	EQU	02H
TTYDA	EQU	02H
TTYTR	EQU	01H
;
	ORG	0H
	JMP	INITA		;DEAD START
	JMP	EOR		;RESTART MONITOR
;
	ORG	08H
	JMP	BRKP		;BREAKPOINT RESTART
;
	ORG	40H;
;
; THIS ROUTINE SETS UP THE SIO BOARD
;
INITA:	MVI	A,0AAH		;GET DUMMY MODE WORD
	OUT	TTS		;OUTPUT IT
	MVI	A,40H		;GET RESET BIT
	OUT	TTS		;RESET SIO BOARD
	MVI	A,0CEH		;GET REAL MODE WORD
	OUT	TTS		;SET THE MODE FOR REAL
	MVI	A,37H		;GET THE COMMAND
	OUT	TTS		;OUTPUT IT
;
; THIS ROUTINE INITIALIZES THE FILE AREAD FOR SUBSEQUENT
; PROCESSING
;
	LXI	H,FILE0
	MVI	C,MAXFIL*FELEN
	XRA	A
INIT2:	MOV	M,A
	INX	H
	DCR	C
	JNZ	INIT2
;
; CLEAR THE BREAKPOINT TABLE
;
	MVI	B,NBR*3
	LXI	H,BRT
INIT3:	MOV	M,A
	INX	H
	DCR	B
	JNZ	INIT3
;
; THIS IS THE STARTING POINT OF THE SELF CONTAINED
; SYSTEM ONCE THE SYSTEM HAS BEEN INITIALIZED.  COMMANDS
; ARE READ FROM THE USER, EXECUTED, AND CONTROL RETURNS
; BACK TO THIS POINT TO READ ANOTHER COMMAND.
;
EOR:	LXI	SP,AREA+18
	CALL	CRLF		;PRINT C/R, LINE FEED
	CALL	READ		;READ INPUT LINE
	INX	H
	MOV	A,M		;FETCH FIRST CHARACTER
	CPI	'9'+1		;COMMAND OR LINE NUMBER?
	JC	LINE		;JUMP IF LINE FOR FILE
	CALL	VALC
	CALL	COMM
	JMP	EOR
;
; THIS ROUTINE READS IN A LINE FROM THE TTY AND PLACES
; IT IN AN INPUT BUFFER.
; THE FOLLOWING ARE SPECIAL CHARACTERS
;   CR          TERMINATES READ ROUTINE
;   LF          NOT RECOGNIZED BY ROUTINE
;   CTRL X      DELETES CURRENT LINE
;   DEL         DELETES CHARACER
; ALL DISPLAYABLE CHARACTERS BETWEEN BLANK & Z AND THE
; ABOVE ARE RECOGNIZED BY THE READ ROUTINE, ALL OTHERS
; ARE SKIPPED OVER.  THE ROUTINE WILL NOT ACCEPT MORE
; CHARACTERS THAN THE INPUT BUFFER WILL HOLD.
;
READ:	LXI	H,IBUF		;GET INPUT BUFFER ADDRESS
	SHLD	ADDS		;SAVE ADDRESS
	MVI	E,2		;INITIALIZE CHARACTER COUNT
NEXT:	CALL	IN8		;READ A LINE
	MOV	A,B
	CPI	24		;CHECK FOR CTRL X
	JNZ	CR
	CALL	CRLF		;OUTPUT A CRLF
	JMP	READ
CR:	CPI	ASCR		;GET AN ASCII CR
	JNZ	DEL
	MOV	A,L
	CPI	IBUF AND 00FFH	;CHECK FOR FIRST CHAR
	JZ	READ
	MVI	M,ASCR		;PLACE CR AT END OF LINE
	INX	H
	MVI	M,1		;PLACE EOF INDICATOR IN LINE
	INX	H
	MVI	A,IBUF+83 AND 00FFH
	CALL	CLER		;CLEAR REMAINING BUFFER
	LXI	H,IBUF-1
	MOV	M,E		;SAVE CHARACTER COUNT
	RET
DEL:	CPI	127		;CHECK FOR DELETE CHARACTER
	JNZ	CHAR
	MVI	A,IBUF AND 00FFH
	CMP	L		;IS IT 1ST CHARACTER
	JZ	NEXT
	DCX	H		;DECREMENT POINTER
	DCR	E		;DECREMENT COUNT
BSPA:	MVI	B,5FH
	CALL	OUT8
	JMP	NEXT
CHAR:	CPI	' '		;CHECK FOR LEGAL CHARACTER
	JC	NEXT
	CPI	'Z'+1
	JNC	NEXT
	MOV	B,A
	CALL	OUT8		;ECHO CHARACTER
	MOV	M,B
	MVI	A,IBUF+81 AND 00FFH
	CMP	L		;CHECK FOR END OF LINE
	JZ	BSPA
	INX	H
	INR	E		;INCREMENT CHARACTER COUNT
	JMP	NEXT
;
; THIS ROUTINE IS USED TO BLANK OUT A PORTION OF MEMORY
;
CLER:	CMP	L
	RZ	
	MVI	M,' '		;PLACE BLANK IN MEMORY
	INX	H
	JMP	CLER
;
; SEE IF TTY INPUT READY AND CHECK FOR CTRL X.
;
INK:	IN	TTS		;GET TTY STATUS
	CMA			;INVERT STATUS
	ANI	TTYDA		;IS DATA AVAILABLE?
	RNZ			;RETURN IF NOT
	IN	TTI		;GET THE CHAR
	ANI	07FH		;STRIP OFF PARITY
	CPI	'X'-40H		;IS IT A CTRL X?
	RET
;
; THIS ROUTINE READS A BYTE OF DATA FROM THE USART
;
IN8:	IN	TTS		;READ USART STATUS
	ANI	TTYDA
	JZ	IN8
	IN	TTI		;READ DATA
	ANI	127		;STRIP OFF PARITY
	MOV	B,A
	RET

;
; THIS ROUTINE OUTPUTS A BYTE OF DATA TO THE USART
;
OUT8:	IN	TTS		;READ STATUS
	ANI	TTYTR
	JZ	OUT8
OK:	MOV	A,B
	OUT	TTO		;TRANSMIT DATA
	RET
;
; THIS ROUTINE WILL OUTPUT A CARRIAGE RETURN AND
; LINE FEED FOLLOWED BY TWO DELETE CHARACTERS WHICH
; PROVIDE TIME FOR PRINT HEAD TO RETURN.
;
CRLF:	MVI	B,13		;CR
	CALL	OUT8
LF:	MVI	B,10		;LF
	CALL	OUT8
	MVI	B,127
	CALL	OUT8
	CALL	OUT8
	RET
;
; THIS ROUTINE JUMPS TO A LOCATION IN MEMORY GIVEN BY
; THE INPUT COMMAND AND BEGINS EXECUTION OF PROGRAM
; THERE.
;
EXEC:	CALL	VCHK		;CHECK FOR PARAMETERS
	CALL	CRLF
	LHLD	BBUF		;FETCH ADDRESS
	PCHL			;JUMP TO PROGRAM
;
; THIS ROUTINE CHECKS THE INPUT COMMAND AGAINS ALL
; LEGAL COMMANDS STORED IN A TABLE.  IF A LEGAL COMMAND
; IS FOUND, A JUMP IS MADE TO THAT ROUTINE.  OTHERWISE
; AN ERROR MESSAGE IS OUTPUT TO THE USER.
;
COMM:	LXI	D,CTAB		;COMMAND TABLE ADDRESS
	MVI	B,NCOM		;NUMBER OF COMMANDS
	MVI	A,4		;LENGTH OF COMMAND
	STA	NCHR		;SAVE
	CALL	COMS		;SEARCH TABLE
	JNZ	WHAT		;JUMP IF ILLEGAL COMMAND
	PCHL			;BE HERE NOW
;
; THIS ROUTINE CHECKS TO SEE IF A BASE CHARACTER STRING
; IS EQUAL TO ANY OF THE STRINGS CONTAINED IN A TABLE
; POINTED TO BY D,E.  tHE TABLE CONSISTS OF ANY NUMBER
; OF CHARS, WITH 2 BYTES CONTAINING VALUES ASSOCIATED
; WITH IT.  REG B CONTAINS THE # OF STRINGS TO COMPARE.
; THIS ROUTINE CAN BE USED TO SEARCH THROUGH A COMMAND
; OR SYMBOL TABLE.  ON RETURN, IF THE ZERO FLAG IS SET,
; A MATCH WAS FOUND; IF NOT, NO MATCH WAS FOUND.  IF
; A MATCH WAS FOUND, D,E POINT TO THE LAST BYTE
; ASSOCIATED WITH THE CHARACTER STRING.  iF NOT, D,E
; POINT TO THE NEXT LOCATION AFTER THE END FO THE TABLE.
;
COMS:	LHLD	ADDS		;FETCH COMPARE ADDRESS
	LDA	NCHR		;GET LENGTH OF STRING
	MOV	C,A
	CALL	SEAR		;COMPARE STRINGS
	LDAX	D		;FETCH VALUE
	MOV	L,A
	INX	D
	LDAX	D		;FETCH VALUE
	MOV	H,A
	RZ	
	INX	D		;SET TO NEXT STRING
	DCR	B		;DECREMENT COUNT
	JNZ	COMS
	INR	B		;CLEAR ZERO FLAG
	RET
;
; THIS ROUTINE CHECKS TO SEE IF TWO CHARACTER STRINGS IN
; MEMORY ARE EQUAL.  tHE STRINGS ARE POINTED TO BY D,E
; AND H,L.  ON RETURN, THE ZERO FLAG SET INDICATES A
; MATCH.  REG C INDICATES THE LENGTH OF THE STRINGS.  ON
; RETURN, THE POINTERS POINT TO THE NEXT ADDRESS AFTER
; THE CHARACTER STRINGS.
;
SEAR:	LDAX	D		;FETCH CHARACTER
	CMP	M		;COMPARE CHARACTERS
	JNZ	INCA
	INX	H
	INX	D
	DCR	C		;DECREMENT CHARACTER COUNT
	JNZ	SEAR
	RET
INCA:	INX	D
	DCR	C
	JNZ	INCA
	INR	C		;CLEAR ZERO FLAG
	RET
;
; THIS ROUTINE ZEROES OUT A BUFFER IN MEMORY WHICH IS
; THEN USED BY OTHER SCANNING ROUTINES
;
ZBUF:	XRA	A		;GET A ZERO
	LXI	D,ABUF+12	;BUFFER ADDRESS
	MVI	B,12		;BUFFER LENGTH
ZBU1:	DCX	D		;DECREMENT ADDRESS
	STAX	D		;ZERO BUFFER
	DCR	B
	JNZ	ZBU1
	RET
;
; THIS ROUTINE CALLS ETRA TO OBTAIN THE INPUT PARAMETER
; VALUES AND CALLS AN ERROR ROUTINE IF AN ERROR OCCURED
; IN THAT ROUTINE
;
VALC:	CALL	ETRA		;GET INPUT PARAMETERS
	JC	WHAT		;JUMP IF ERROR
	RET
;
; THIS ROUTINE EXTRACTS THE VALUES ASSOCIATED WITH A
; COMMAND FROM THE INPUT STREAM AND PLACES THEM IN THE
; ASCII BUFFER (ABUF).  IT ALSO CALLS A ROUTINE TO
; CONVERT THE ASCII HEXADECIMALS TO BINARY AND STORES
; THEM IN THE BINARY BUFFER (BBUF).  ON RETURN, CARRY
; SET INDICATES AN ERROR IN INPUT PARAMETERS.
;
ETRA:	LXI	H,0		;GET A ZERO
	SHLD	BBUF+2		;ZERO VALUE
	SHLD	FBUF		;SET NO FILE NAME
	CALL	ZBUF		;ZERO BUFFER
	LXI	H,IBUF-1
VAL1:	INX	H
	MOV	A,M		;FETCH INPUT CHARACTER
	CPI	' '		;LOOK FOR FIRST CHARACTER
	CMC
	RNC			;RETURN IF NO CARRY
	JNZ	VAL1		;JUMP IF NO BLACK
	SHLD	PNTR		;SAVE POINTER
	CALL	SBLK		;SCAN TO FIRST PARAMETER
	CMC
	RNC			;RETURN IF CR
	CPI	'/'
	JNZ	VAL5		;NO FILE NAME
	LXI	D,FBUF		;NAME FOLLOWS PUT IN FBUF
	MVI	C,NMLEN
VAL2:	INX	H
	MOV	A,M
	CPI	'/'
	JZ	VAL3
	DCR	C
	JM	WHAT
	STAX	D		;STORE FILE NAME
	INX	D
	JMP	VAL2
VAL3:	MVI	A,' '		;GET AN ASCII SPACE
VAL4:	DCR	C
	JM	DONE
	STAX	D		;FILL IN WITH SPACES
	INX	D
	JMP	VAL4
DONE:	CALL	SBL2
	CMC
	RNC
VAL5:	LXI	D,ABUF
	CALL	ALPS		;PLACE PARAMETER IN BUFFER
	MOV	A,B		;GET DIGIT COUNT
	CPI	5		;CHECK NUMBER OF DIGITS
	CMC
	RC			;RETURN IF TOO MANY DIGITS
	LXI	B,ABUF
	CALL	AHEX		;CONVERT VALUE
	RC			;ILLEGAL CHARACTER
	SHLD	BBUF		;SAVE IN BINARY BUFFER
	LXI	H,ABUF
	CALL	NORM		;NORMALIZE ASCII VALUE
	CALL	SBLK		;SCAN TO NEXT PARAMETER
	CMC
	RNC			;RETURN IF cr
	LXI	D,ABUF+4
	CALL	ALPS		;PLACE PARAMETERS IN BUFFER
	MOV	A,B		;GET DIGIT COUNT
	CPI	5		;CHECK NUMBER OF DIGITS
	CMC
	RC			;RETURN IF TOO MANY DIGITS
	LXI	B,ABUF+4
	CALL	AHEX		;CONVERT VALUE
	RC			;ILLEGAL VALUE
	SHLD	BBUF+2		;SAVE IN BINARY BUFFER
	LXI	H,ABUF+4
	CALL	NORM		;NORMALIZE ASCII VALUE
	ORA	A		;CLEAR CARRY
	RET
;
; THIS ROUTINE FETCHES DIGITS FROM THE BUFFER ADDRESSED
; BY B,C AND CONVERTS THE ASCII DECIMAL DIGITS INTO
; BINARY.  UP TO A 16-BIT VALUE CAN BE CONVERTED.  THE
; SCAN STOPS WHEN A BINARY ZERO IS FOUND IN THE BUFFER.
;
ADEC:	LXI	H,0		;GET A 16 BIT ZERO
ADE1:	LDAX	B		;FETCH ASCII DIGIT
	ORA	A		;SET ZERO FLAG
	RZ			;RETURN IFF FINISHED
	MOV	D,H		;SAVE CURRENT VALUE
	MOV	E,L		;SAVE CURRENT VALUE
	DAD	H		;TIMES TWO
	DAD	H		;TIMES TWO
	DAD	D		;ADD IN ORIGINAL VALUE
	DAD	H		;TIMES TWO
	SUI	48		;ASCII BIAS
	CPI	10		;CHECK FOR LEGAL VALUE
	CMC
	RC			;RETURN IF ERROR
	MOV	E,A
	MVI	D,0
	DAD	D		;ADD IN NEXT DIGIT
	INX	B		;INCREMENT POINTER
	JMP	ADE1
;
; THIS ROUTINE FETCHES DIGITS FROM THE BUFFER ADDRESSED
; BY B,C AND CONVERTS THE ASCII HEXADECIMAL DIGITS INTO
; BINARY.  UP TO A 16-BIT VALUE CAN BE CONVERTED.  THE
; SCAN STOPS WHEN A BINARY ZERO IS FOUNDIN THE BUFFER.
;
AHEX:	LXI	H,0		;GET A 16 BIT ZERO
AHE1:	LDAX	B		;FETCH ASCII DIGIT
	ORA	A		;SET ZERO FLAG
	RZ			;RETURN IF DONE
	DAD	H		;LEFT SHIFT
	DAD	H		;LEFT SHIFT
	DAD	H		;LEFT SHIFT
	DAD	H		;LEFT SHIFT
	CALL	AHS1		;CONVERT TO BINARY
	CPI	10H		;CHECK FOR LEGAL VALUE
	CMC
	RC			;RETURN IF ERROR
	ADD	L
	MOV	L,A
	INX	B		;INCREMENT POINTER
	JMP	AHE1
;
; THIS ROUTINE CONVERTS ASCII HEX DIGITS INTO BINARY
;
AHS1:	SUI	48		;ASCII BIAS
	CPI	10		;DIGIT 0-10
	RC
	SUI	7		;ALPHA BIAS
	RET
;
; THIS ROUTINE CONVERTS A BINARY VALUE TO ASCII
; HEXADECIMAL AND OUTPUTS THE CHARACTERS TO THE TTY.
;
HOUT:	CALL	BINH
	LXI	H,HCON
CHOT:	MOV	B,M
	CALL	OUT8
	INX	H
	MOV	B,M
	CALL	OUT8
	RET
;
; THIS ROUTINE DOES THE SAME AS ABOVE BUT OUTPUTS A
; BLANK AFTER THE LAST CHARACTER
;
HOTB:	CALL	HOUT		;CONVERT AND OUTPUT
	CALL	BLK1		;OUTPUT A BLANK
	RET
;
; THIS ROUTINE CONVERTS A BINARY VALUE TO ASCII
; DECIMAL DIGITS AND OPTPUTS THE CHARACTERS TO THE TTY
;

DOUT:	CALL	BIND		;CONVERT VALUE
	CALL	HOUT+3		;OUTPUT VALUE (2 DIGITS)
	INX	H
	MOV	B,M		;GET LAST DIGIT
	CALL	OUT8		;OUTPUT
	RET
;
; THIS ROUTINE OUTPUTS A BLANK
;
BLK1:	MVI	B,' '		;GET A BLANK
	CALL	OUT8
	RET
;
; THIS ROUTINE IS USED BY OTHER ROUTINES TO INCREMENT
; THE STARTING ADDRESS IN A COMMAND AND COMPARE IT WITH
; THE FINAL ADDRESS IN THE COMMAND.  ON RETURN, THE
; CARRY FLAG SET INDICATES THAT THE FINAL ADDRESS HAS
; BEEN REACHED.
;
ACHK:	LHLD	BBUF		;FETCH START ADDRESS
	LDA	BBUF+3		;STOP ADDRESS (HIGH)
	CMP	H		;COMPARE ADDRESSES
	JNZ	ACH1
	LDA	BBUF+2		;STOP ADDRESS (LOW)
	CMP	L		;COMPARE ADDRESSES
	JNZ	ACH1
	STC			;SET CARRY IF EQUAL
ACH1:	INX	H		;INCREMENT START ADDRESSES
	SHLD	BBUF		;STORE START ADDRESS
	RET
;
; THIS ROUTINE OUTPUTS CHARACTER OF A STRING
; UNTIL A CARRIAGE RETURN IS FOUND
;
SCRN:	MOV	B,M		;FETCH CHARACTER
	MVI	A,13		;CARRIAGE RETURN
	CMP	B		;CHARACTER = CR?
	RZ	
	CALL	OUT8
	INX	H
	JMP	SCRN
;
; THIS ROUTINE CONVERTS THE BINARY VALUE IN REG A INTO
; ASCII HEXADECIMAL DIGITS AND STORES THEM IN MEMORY
;
BINH:	LXI	H,HCON		;CONVERSION
	MOV	B,A		;SAVE VALUE
	RAR
	RAR
	RAR
	RAR
	CALL	BIN1
	MOV	M,A
	INX	H
	MOV	A,B
	CALL	BIN1		;CONVERT TO ASCII
	MOV	M,A
	RET
;
; THIS ROUTINE CONVERTS A VALUE TO HEXADECIMAL
;
BIN1:	ANI	0FH		;LOW 4 BITS
	ADI	48		;CONVERT TO ASCII
	CPI	58		;DIGIT 0-9
	RC
	ADI	7		;MODIFY FOR A-F
	RET
;
; THIS ROUTINE CONVERTS THE BINARY VALUE IN REG A INTO
; ASCII DECIMAL DIGITS AND STORES THEM IN MEMORY
;
BIND:	LXI	H,HCON		;CONVERSION ADDRESS
	MVI	B,100
	CALL	BID1		;CONVERT HUNDREDS DIGIT
	MVI	B,10
	CALL	BID1		;CONVERT TENS DIGIT
	ADI	'0'		;GET UNITS DIGIT
	MOV	M,A		;STORE IN MEMORY
	RET
;
; THIS ROUTINE CONVERTS A VALUE TO DECIMAL
;
BID1:	MVI	M,'0'-1		;INITIALIZE DIGIT COUNT
	INR	M
	SUB	B		;CHECK DIGIT
	JNC	BID1+2
	ADD	B		;RESTORE VALUE
	INX	H
	RET
;
; LEGAL COMMAND TABLE
;
CTAB:	DB	'DUMP'
	DW	DUMP
	DB	'EXEC'
	DW	EXEC
	DB	'ENTR'
	DW	ENTR
	DB	'FILE'
	DW	FILE
	DB	'LIST'
	DW	LIST
	DB	'DELT'
	DW	DELL
	DB	'ASSM'
	DW	ASSM
	DB	'PAGE'
	DW	PAGEMOV
	DB	'CUST'
	DW	2000H
	DB	'BREK'
	DW	BREAK
	DB	'PROC'
	DW	PROC
;
; THIS ROUTINE CHECKS IF ANY PARAMETERS WERE ENTERED
; WITH THE COMMAND, IF NOT AN ERROR MESSAGE IS ISSUED
;
VCHK:	LDA	ABUF		;FETCH PARAMETER BYTE
	ORA	A		;SET FLAGS
	JZ	WHAT		;NO PARAMETER
	RET
;
; THIS ROUTINE DUMPS OUT THE FONTENTS OF MEMORY FROM
; THE START TO FINAL ADDRESSES GIVEN IN THE COMMAND.
;
DUMP:	CALL	VCHK		;CHECK FOR PARAMETERS
DUMS:	CALL	CRLF		;START NEW LINE
DUM1:	LHLD	BBUF		;FETCH MEMORY ADDRESS
	MOV	A,M
	CALL	HOTB		;OUTPUT VALUE
	CALL	ACHK		;CHECK ADDRESS
	RC			;RETURN IF FINISHED
	MOV	A,L		;IS NEXT ADDRESS
	ANI	0FH		; DIVISIBLE BY 16?
	JNZ	DUM1
	JMP	DUMS
;
; THIS ROUTINE WILL MOVE 256 BYTES FROM 1ST ADDRESS
; GIVEN IN COMMAND TO 2ND ADDRESS IN COMMAND.
;
PAGEMOV:CALL	VCHK		;CHECK FOR PARAMETER
	LDA	ABUF+4		;FETCH 2ND PARAMETER
	ORA	A		;DOES 2ND PARAMETER EXIST?
	JZ	WHAT
	LHLD	BBUF		;FETCH MOVE TO ADDRESS
	XCHG
	LHLD	BBUF+2		;FETCH MOVE TO ADDRESS
	MVI	B,0		;SET COUNTER
PAG1:	LDAX	D
	MOV	M,A
	INX	H
	INX	D
	DCR	B		;DECREMENT COUNTER
	JNZ	PAG1
	RET
;
; THIS COMMAND INITIALIZES THE BEGINNING OF FILE ADDRESS
; AND END OF FILE ADDRESS AS WELL AS THE FILE AREA
; WHEN THE FILE COMMAND IS USED
;
FILE:	CALL	CRLF
; CHECK FOR FILE PARAMETERS
	LDA	FBUF
	ORA	A
	JZ	FOUT		;NO ? GO LIST
	CALL	FSEA		;LOOK UP FILE
	XCHG 			;PNTR IN DE
	JNZ	TEST
; NO ENTRY
	LDA	ABUF		;CHECK FOR PARAM
	ORA	A
	JZ	WHA1		;NO?? - ERROR
; CHECK FOR ROOM IN DIRECTORY
	LDA	FEF
	ORA	A
	JNZ	ROOM
	LXI	H,EMES1
	JMP	MESS
; ENTRY FOUND ARE THESE PARAMETERS
TEST:	LDA	ABUF
	ORA	A
	JZ	SWAPS
	LHLD	BBUF
	MOV	A,H
	ORA	L
	JZ	SWAPS
	LXI	H,EMES2		;NO-NO CAN?T DO
	JMP	MESS		;IT - DELETE FIRST
; MOVE FILE NAME TO BLOCK POINTED TO BY FREAD
ROOM:	LHLD	FREAD
	XCHG
	LXI	H,FBUF		;FILE NAME POINTER IN H,L
	PUSH	D
	MVI	C,NMLEN		;NAME LENGTH COUNT
MOV23:	MOV	A,M
	STAX	D
	INX	D
	DCR	C		;TEST COUNT
	INX	H
	JNZ	MOV23
	POP	D		;RESTORE ENTRY POINTER
; MAKE FILE POINTED TO BY D,E CURRENT
SWAPS:	LXI	H,FILE0
	MVI	C,FELEN		;ENTRY LENGTH
SWAP:	LDAX	D
	MOV	B,M
	MOV	M,A		;EXCHANGE
	MOV	A,B
	STAX	D
	INX	D
	INX	H		;BUMP POINTER
	DCR	C		;TEST COUNT
	JNZ	SWAP

; CHECK FOR 2ND PARAMETER
            LDA	ABUF
	ORA	A
	JZ	FOOT		;NO SECOND PARAMETER
; PROCESS 2ND PARAMETER
	LHLD	BBUF		;GET ADDRESS
	SHLD	BOFP		;SET BEGIN
	SHLD	EOFP		;SET END
	MOV	A,L		;IS ADDRESS ZERO
	ORA	H
	JZ	FIL35		;YES
FIL30:	MVI	M,1		;NON-ZERO ? SET EOF
FIL35:	XRA	A		;AND MAX LINE #
	STA	MAXL
	JMP	FOOT		;OUTPUT PARAMETERS
FOUT:	LDA	IBUF+4
	CPI	'S'		;IS COMMAND FILES?
	MVI	C,MAXFIL
	JZ	FOUL
FOOT:	MVI	C,1
; OUTPUT THE # OF ENTRIES IN C
FOUL:	LXI	H,FILE0
	MOV	A,C
FINE:	STA	FOCNT		;SAVE COUNT
	PUSH	H
	LXI	D,NMLEN
	DAD	D
	MOV	A,M
	ORA	A
	JNZ	FOOD
	INX	H
	ADD	M
	INX	H
	JNZ	FOOD		;NON ZERO, OK TO OUTPUT
	INX	SP
	INX	SP
	INX	H
	INX	H
	JMP	FEET
; HAVE AN ENTRY TO OUTPUT
FOOD:	POP	H		;PTR
	MVI	C,NMLEN
FAST:	MOV	B,M		;LOAD CHARACTER TO B
	CALL	OUT8
	DCR	C
	INX	H
	JNZ	FAST		;DO THE REST
; NOW OUTPUT BEGIN-END PTRS
	CALL	FOOL		;OUTPUT BEGIN
	CALL	FOOL		;OUTPUT END
	CALL	CRLF		;AND C/R
; TEST COUNT, H,L POINTS PAST EOFP
FEET:	LXI	D,FELEN-NMLEN-4
	DAD	D		;MOVE TO NEXT ENTRY
	LDA	FOCNT
	DCR	A		;TEST COUNT
	JNZ	FINE		;MORE TO DO
	RET			;DONE!
; OUTPUT NUMBER POINTED TO BY H,L
; ON RET, H,L POINT 2 WORDS LATER
FOOL:	CALL	BLK1		;SPACE
	INX	H
	MOV	A,M
	DCX	H
	PUSH	H
	CALL	HOUT		;OUTPUT
	POP	H
	MOV	A,M
	INX	H
	INX	H
	PUSH	H
	CALL	HOTB		;OUTPUT
	POP	H		;RESTORE H,L
	RET
;
; SEARCH THE FILE DIRECTORY FOR THE FILE
; WHOSE NAME IS IN FBUF.
; RETURN IF FOUND, ZERO IF OFF, H,L POINT TO
; ENTRY WHILE SEARCHING, ON ENTRY FOUND WITH ADDR
; ZERO, SET FEF TO >0 AND FREAD TO THE ADDR OF ENTRY
;
FSEA:	XRA	A
	STA	FEF		;CLAIM NO FREE ENTRIES
	MVI	B,MAXFIL	;COUNT OF ENTRIES
	LXI	D,FILE0		;TABLE ADDRESS
FSE10:	LXI	H,FBUF
	MVI	C,NMLEN
	CALL	SEAR		;TEST STRINGS
	PUSH	PSW		;SAVE FLAG
	PUSH	D
	LDAX	D		;GET BOFP
	ORA	A		;EMPTY ENTRY?
	JNZ	FSE20
	INX	D		;STORE OTHER WORD
	LDAX	D
	ORA	A
	JNZ	FSE20		;NOPE-GO TEST FOR MATCH
	XCHG
	LXI	D,-NMLEN-1
	DAD	D		;MOVE TO BEGINNING
	SHLD	FREAD		;SAVE ADDR
	MOV	A,D
	STA	FEF		;SET FREE ENTRY FOUND
	POP	H		;RESTORE INTERIM PTR
	POP	PSW		;UNJUNK STACK
; MOVE TO NEXT ENTRY
FSE15:	LXI	D,FELEN-NMLEN
	DAD	D
	XCHG			;NEXT ENTRY IN DE
	DCR	B		;TEST COUNT
	RZ			;DONE--NOPE
	JMP	FSE10		;TRY NEXT
; ENTRY WASN?T FREE, TEST FOR MATCH
FSE20:	POP	H
	POP	PSW
	JNZ	FSE15		;IF ZERO CLEAR, NO MATCH
; ENTRY FOUND
	LXI	D,-NMLEN	;BACKUP
	DAD	D		;H,L POINTS TO ENTRY
	MOV	A,D
	ORA	A		;CLEAR ZERO
	RET			;THAT?S ALL
;
; OUTPUT ERROR MESSAGE FOR ILLEGAL COMMAND
;
WHAT:	CALL	CRLF		;OUT CRLF
WHA1:	LXI	H,EMES		;MESSAGE ADDRESS
MESS:	CALL	SCRN
	JMP	EOR
;
EMES:	DB	'WHAT'
	DB	13
EMES1:	DB	'FULL',13
EMES2:	DB	'NO NO',13
;
; CALL ROUTINE TO ENTER DATA INTO MEMORY
; AND CHECK FOR ERROR ON RETURN
;
; THIS ROUTINE IS USED TO ENTER DATA VALUES INTO MEMORY.
; EACH VALUE IS ONE BYTE AND IS WRITTEN IN HEXADECIMAL
; VALUES GREATER THAN 255 WILL CAUSE CARRY TO BE SET
; AND RETURN TO BE MADE TO CALLING PROGRAM
;
ENTR:	CALL	VCHK		;CHECK FOR PARAMETERS
	CALL	ENTS
	JC	WHAT
	CALL	CRLF
	RET
;
EEND	EQU	'/'		;TERMINATION CHARACTER
ENTS:	CALL	CRLF
	CALL	READ		;READ INPUT DATA
	LXI	H,IBUF		;SET LINE POINTER
	SHLD	PNTR		;SAVE POINTER
ENT1:	CALL	ZBUF		;CLEAR BUFFER
	CALL	SBLK		;SCAN TO FIRST VALUE
	JC	ENTS		;JUMP IF CR FOUND
	CPI	EEND
	RZ			;RETURN CARRY IS ZERO
	CALL	ALPS		;PLACE VALUE IN BUFFER
	MOV	A,B		;GET DIGIT COUNT
	CPI	3		;CHECK NMBR OF DIGITS
	CMC
	RC			;RETURN IF MORE THAN 2 DIGITS
	LXI	B,ABUF		;CONVERSION ADDRESS
	CALL	AHEX		;CONVERT VALUE
	RC			;ERROR IN HEX CHARACTER
	MOV	A,L
	LHLD	BBUF		;FETCH MEMORY ADDRESS
	MOV	M,A		;PUT IN MEMORY
	CALL	ACH1		;INCREMENT MEMORY LOCATION
	JMP	ENT1
;
; THIS ROUTINE IS USED TO ENTER LINES INTO THE FILE
; AREA.  THE LINE NUMBER IS FIRST CHECKED TO SEE IF IT IS
; A VALID NUMBER (0000-9999).  NEXT IT IS CHECKED TO SEE
; IF IT IS GREATER THAN THE MAXIMUM CURRENT LINE NUMBER.
; IF IT IS, THE NEXT LINE IS INSERTED AT THE END OF THE
; CURRENT FILE AND THE MAXIMUM LINE NUMBER IS UPDATED AS
; WELL AS THE END OF FILE POSITION.  LINE NUMBERS THAT
; ALREADY EXIST ARE INSERTED INTO THE FILE AREA AT THE
; APPROPRIATE PLACE AND ANY EXTRA CHARACTERS IN THE OLD
; LINE ARE DELETED.
;
LINE:	LDA	FILE0		;IS A FILE DEFINED?
	ORA	A
	JZ	WHAT		;ABORT IF NOT
	MVI	C,4		;NO OF DIGITS TO CHECK
	LXI	H,IBUF-1		;INITIALIZE ADDRESS
LICK:	INX	H
	MOV	A,M		;FETCH LINE DIGIT
	CPI	'0'		;CHECK FOR VALID NUMBER
	JC	WHAT
	CPI	'9'+1
	JNC	WHAT
	DCR	C
	JNZ	LICK
	SHLD	ADDS		;FIND ADDRESS
	LXI	D,MAXL+3		;GET ADDRESS
	CALL	COM0
	JNC	INSR
; GET HERE IF NEW LINE IS GREATER THAN MAXIMUM LINE #
	INX	H
	CALL	LODM		;GET NEW LINE NUMBER
	LXI	H,MAXL+3
	CALL	STOM		;MAKE IT MAXIMUM LINE NUMBER
	LXI	D,IBUF-1
	LHLD	EOFP		;END OF FILE POSITION
	MVI	C,1
	CALL	LMOV		;PLACE LINE IN FILE
SEOF:	MVI	M,1		;END OF FILE INDICATOR
	SHLD	EOFP		;END OF FILE ADDRESS
	JMP	EOR
; GET HERE IF NEW LINE MUST BE INSERTED INTO ALREADY
; EISTING FILE AREA
INSR:	CALL	FIN1		;FIND LINE IN FILE
	MVI	C,2
	JZ	EQUL
	DCR	C		;NEW LN NOT EQUAL TO SOME OLD LN
EQUL:	MOV	B,M
	DCX	H
	MVI	M,2		;MOVE LINE INDICATOR
	SHLD	INSP		;INSERT LINE POSITION
	LDA	IBUF-1		;NEW LINE COUNT
	DCR	C
	JZ	LESS		;NEW LN NOT = OLD LN
	SUB	B		;COUNT DIFFERENCE
	JZ	ZERO		;LINE LENGTHS EQUAL
	JC	MORE
; GET HERE IF # OF CHARS IN OLD LINE > # OF CHARS IN
; NEW LINE OR NEW LINE # WAS NOT EQUAL TO SOLD OLD
; LINE #
LESS:	LHLD	EOFP		;END OF FILE ADDRESS
	MOV	D,H
	MOV	E,L
	CALL	ADR		;MOVE TO ADDRESS
	SHLD	EOFP		;NEW END OF FILE ADDRESS
	MVI	C,2
	CALL	RMOV		;OPEN UP FILE AREA
	JMP	ZERO
; GET HERE IF # OF CHARS IN OLD LINE < # OF CHARS IN
; NEW LINE
MORE:	CMA
	INR	A		;COUNT DIFFERENCE
	MOV	D,H
	MOV	E,L
	CALL	ADR
	XCHG
	CALL	LMOV		;DELETE EXCESS CHAR IN FILE
	MVI	M,1		;E-O-F INDICATOR
	SHLD	EOFP		;E-O-F ADDRESS
; GET HERE TO INSERT LINE INTO FILE AREA
ZERO:	LHLD	INSP		;INSERT ADDRESS
	MVI	M,ASCR
	INX	H
	LXI	D,IBUF-1		;NEW LINE ADDRESS
	MVI	C,1		;CHECK VALUE
	CALL	LMOV		;PLACE LINE IN FILE
	JMP	EOR
;
; THIS ROUTINE IS USED TO FIND A LN IN THE FILE AREA
; WHICH IS GREATER THAN OR EQUAL TO THE CURRENT LINE #
;
FIND:	LXI	H,ABUF+3		;BUFFER ADDRESS
	SHLD	ADDS		;SAVE ADDRESS
FIN1:	LHLD	BOFP		;BEGIN FILE ADDRESS
	MOV	A,H		;RETURN TO MONITOR IF
	ORA	L		;  FILE IS EMPTY...
	JZ	EOR
FI1:	CALL	EO1		;CHECK FOR END OF FILE
	XCHG
	LHLD	ADDS		;FETCH FIND ADDRESS
	XCHG
	MVI	A,4
	CALL	ADR		;BUMP LINE ADDRESS
	CALL	COM0		;COMPARE LINE NUMBERS
	RC
	RZ	
FI2:	MOV	A,M
	CALL	ADR		;NEXT LINE ADDRESS
	JMP	FI1
;
; WHEN SEARCHING THROUGH THE FILE AREA, THIS ROUTINE
; CHECKS TO SEE IF THE CURRENT ADDRESS IS THE END OF
; FILE
;
EOF:	INX	H
EO1:	MVI	A,1		;E-O-F INDICATOR
	CMP	M
	RNZ
	JMP	EOR
;
; THIS ROUTINE IS USED TO ADD A VALUE TO AN ADDRESS
; CONTAINED IN REGISTER H,L
;
ADR:	ADD	L
	MOV	L,A
	RNC
	INR	H
	RET
;
; THIS ROUTINE WILL MOVE CHARACTER STRINGS FROM ONE
; LOCATION OF MEMORY TO ANOTHER
; CHARACTERS ARE MOVED FROM LOCATION ADDRESSED BY D,E
; TO LOCATION ADDRESSED BY H,L.  ADDITIONAL CHARACTERS
; ARE MOVED BY BUMPING POINTERS UNTIL THE CHARACTER IN
; REG C IS FETCHED.
;
LMOV:	LDAX	D		;FETCH CHARACTER
	INX	D		;INCREMENT FETCH ADDRESS
	CMP	C		;TERMINATION CHARACTER
	RZ	
	MOV	M,A		;STORE CHARACTER
	INX	H		;INCREMENT STORE ADDRESS
	JMP	LMOV
;
; THIS ROUTINE IS SIMILAR TO ABOVE EXCEPT THAT THE
; CHARACTER ADDRESS IS DECREMENTED AFTER EACH FETCH
; AND STORE
;
RMOV:	LDAX	D		;FETCH CHARACTER
	DCX	D		;DECREMENT FETCH CHARACTER
	CMP	C		;TERMINATION CHARACTER
	RZ	
	MOV	M,A		;STORE CHARACTER
	DCX	H		;DECREMENT STORE ADDRESS
	JMP	RMOV
;
; THIS ROUTINE IS USED TO LOAD FOUR CHARACTERS FROM
; MEMORY INTO REGISTERS
;

LODM:	MOV	B,M		;FETCH CHARACTER
	INX	H
	MOV	C,M		;FETCH CHARACTER 
	INX	H
	MOV	D,M		;FETCH CHARACTER 
	INX	H
	MOV	E,M		;FETCH CHARACTER 
	RET
;
; THIS ROUTINE STORES FOUR CHARACTERS FROM THE REGISTERS
; INTO MEMORY
;
STOM:	MOV	M,E		;STORE CHARACTER
	DCX	H
	MOV	M,D		;STORE CHARACTER 
	DCX	H
	MOV	M,C		;STORE CHARACTER 
	DCX	H
	MOV	M,B		;STORE CHARACTER 
	RET
;
; THIS ROUTINE IS USED TO COMPARE TWO CHARACTER STRINGS
; OF LENGTH 4, ON RETURN ZERO FLAG SET MEANS BOTH
; STRINGS ARE EQUAL.  CARRY FLAG =0 MEANS STRING ADDRESS
; BY D,E WAS GREATER THAN OR EQUAL TO CHARACTER STRING
; ADDRESSED BY H,L
;
COM0:	MVI	B,1		;EQUAL COUNTER
	MVI	C,4		;STRING LENGTH
	ORA	A		;CLEAR CARRY
CO1:	LDAX	D		;FETCH CHARACTER
	SBB	M		;COMPARE CHARACTERS
	JZ	CO2
	INR	B		;INCREMENT EQUAL COUNTER
CO2:	DCX	D
	DCX	H
	DCR	C
	JNZ	CO1
	DCR	B
	RET
;
; THIS ROUTINE IS SIMILAR TO THE ABOVE ROUTINE EXCEPT ON
; RETURN CARRY FLAG = 0 MEANS THAT CHARACTER STRING
; ADDRESSED BY D,E IS ONLY > STRING ADDRESSED BY H,L.
;
COM1:	MVI	C,4		;STRING LENGTH
	LDAX	D		;TCH CHARACTER
	SUI	1
	JMP	CO1+1
;
; THIS ROUTINE WILL TAKE ASCII CHARACTERS AND ADD ANY
; NECESSARY ASCII ZEROES SO THE RESULT IS A 4 CHARACTER
; ASCII VALUE
;
NORM:	CALL	LODM		;LOAD CHARACTERS
	XRA	A		;FETCH A ZERO
	CMP	B
	RZ	
NOR1:	CMP	E
	CNZ	STOM		;STORE VALUES
	RNZ
	MOV	E,D		;NORMALIZE VALUE
	MOV	D,C
	MOV	C,B
	MVI	B,'0'
	JMP	NOR1
;
; THIS ROUTINE IS USED TO LIST THE CONTENTS OF THE FILE
; AREA STARTING AT THE LINE NUMBER GIVEN IN THE COMMAND
;
LIST:	CALL	CRLF
	CALL	FIND		;FIND STARTING LINE NUMBER
LIST0:	INX	H		;OUTPUT LINE...
	CALL	SCRN
	CALL	CRLF
	CALL	EOF		;CHECK FOR END OF FILE
	CALL	INK		;CHECK FOR ?X
	JNZ	LIST0		;LOOP IF NO ?X
	RET
;
; THIS ROUTINE IS USED TO DELETE LINES FROM THE
; FILE AREA.  THE REMAINING FILE AREA IS THEN MOVED IN
; MEMORY SO THAT THERE IS NO EXCESS SPACE.
;
DELL:	CALL	VCHK		;CHECK FOR PARAMETER
	CALL	FIND		;FIND LINE IN FILE AREA
	SHLD	DELP		;SAVE DELETE POSITION
	LXI	H,ABUF+7
	MOV	A,M		;CHECK FOR 2ND PARAMETER
	ORA	A		;SET FLAGS
	JNZ	DEL1
	LXI	H,ABUF+3		;USE FIRST PARAMETER
DEL1:	SHLD	ADDS		;SAVE FIND ADDRESS
	XCHG
	LXI	H,MAXL+3
	CALL	COM0		;COMPARE LINE NUMBERS
	LHLD	DELP		;LOAD DELETE POSITION
	JC	NOVR
; GET HERE IF DELETION INVOLVES END OF FILE
	SHLD	EOFP		;CHANGE E-O-F POSITION
	MVI	M,1		;SET E-O-F INDICATOR
	XCHG
	LHLD	BOFP
	XCHG
	MVI	B,13		;SET SCAN SWITCH
	DCX	H		;CHECK FOR BOFP
DEL2:	MOV	A,L
	SUB	E
	MOV	A,H
	SBB	D
	MVI	A,ASCR		;LOOK FOR CR
	JC	DEL4		;DECREMENTED PAST BOF
	DCR	B
	DCX	H
	CMP	M		;FIND NEW MAX LN
	JNZ	DEL2
	DCX	H
	MOV	A,L
	SUB	E
	MOV	A,H
	SBB	D
	JC	DEL5
	CMP	M		;END OF PREVIOUS LINE
	INX	H
	INX	H
	JZ	DEL3
	INX	H
DEL3:	CALL	LODM		;LOAD NEW MAX LN
	LXI	H,MAXL+3		;SET ADDRESS
	CALL	STOM		;STORE NEW MAX LN
	RET
DEL4:	CMP	B		;CHECK SWITCH
DEL5:	XCHG
	JNZ	DEL3-1
	STA	MAXL		;MAKE MAX LN A SMALL NUMBER
	RET
; GET HERE IF DELETION IS IN THE MIDDLE OF FILE AREA
NOVR:	CALL	FI1		;FIND END OF DELETE AREA
	CZ	FI2		;NEXT LINE IF THIS LN EQUAL
NOV1:	XCHG
	LHLD	DELP		;CHAR MOVE TO POSITION
	MVI	C,1		;MOVE TERMINATOR
	CALL	LMOV		;COMPACT FILE AREA
	SHLD	EOFP		;SET EOF POSITION
	MVI	M,1		;SET EOF INDICATOR
	RET
;
; STARTING HERE IS THE SELF ASSEMBLER PROGRAM
; THIS PROGRAM ASSEMBLES PROGRAMS WHICH ARE
; IN THE FILE AREA
;
ASSM:	CALL	VCHK		;CHECK FOR PARAMETERS
	LDA	ABUF+4		;GET 2ND PARAMETER
	ORA	A		;CHECK FOR PRARMETERS
	JNZ	ASM4
	LHLD	BBUF		;FETCH 1ST PARAMETER
	SHLD	BBUF+2		;STORE INTO 2ND PARAMETER
ASM4:	LDA	IBUF+4		;FETCH INPUT CHARACTER
	SUI	'E'		;RESET a IF ERRORS ONLY
	STA	AERR		;SAVE ERROR FLAG
	XRA	A		;GET A ZERO
	STA	NOLA		;INITIALIZE LABEL COUNT
ASM3:	STA	PASI		;SET PASS INDICATOR
	CALL	CRLF		;INDICATE START OF PASS
	LHLD	BBUF		;FETCH ORIGIN
	SHLD	ASPC		;INITIALIZE PC
	LHLD	BOFP		;GET START OF FILE
	SHLD	APNT
ASM1:	LHLD	APNT		;FETCH LINE POINTER
	LXI	SP,AREA+18
	MOV	A,M		;FETCH CHARACTER
	CPI	1		;END OF FILE?
	JZ	EASS		;JUMP IF END OF FILE
	XCHG
	INX	D		;INCREMENT ADDRESS
	LXI	H,OBUF		;BLANK START ADDRESS
	MVI	A,IBUF-5 AND 0FFH	;BLANK END ADDRESS
	CALL	CLER		;BLANK OUT BUFFER
	MVI	C,ASCR		;STOP CHARACTER
	CALL	LMOV		;MOVE LINE INTO BUFFER
	MOV	M,C		;PLACE CR IN BUFFER
	XCHG
	SHLD	APNT		;SAVE ADDRESS
	LDA	PASI		;FETCH PASS INDICATOR
	ORA	A		;SET FLAGW
	JNZ	ASM2		;JUMP IF PASS 2
	CALL	PAS1
	JMP	ASM1
;
ASM2:	CALL	PAS2
	LXI	H,OBUF		;OUTPUT BUFFER ADDRESS
	CALL	AOUT		;OUTPUT LINE
	JMP	ASM1
;
; THIS ROUTINE IS USED TO OUTPUT THE LISTING FOR
; AN ASSEMBLY.  IT CHECKS THE ERROR SWITCH TO SEE IF
; ALL LINES ARE TO BE PRINTED OR JUST THOSE WITH
; ERRORS.
;
AOUT:	LDA	AERR		;FETCH ERROR SWITCH
	ORA	A		;SET FLAGS
	JNZ	AOU1		;OUTPUT ALL LINES
AOU2:	LDA	OBUF		;FETCH ERROR INDICATOR
	CPI	' '		;CHECK FOR AN ERROR
	RZ			;RETURN IF NO ERROR
AOU1:	LXI	H,OBUF		;OUTPUT BUFFER ADDRESS
	CALL	SCRN		;OUTPUT LINE...
	CALL	CRLF
	RET
;
; PASS 1 OF ASSEMBLER, USED TO FORM SYMBOL TABLE
;
PAS1:	CALL	ZBUF		;CLEAR BUFFER
	STA	PASI		;SET FOR PASS1
	LXI	H,IBUF		;INITIALIZE LINE POINTER
	SHLD	PNTR
	MOV	A,M		;FETCH CHARACTER
	CPI	' '		;CHECK FOR A BLANK
	JZ	OPC		;JUMP IF NO LABLE
	CPI	'*'		;CHECK FOR COMMENT
	RZ			;RETURN IF COMMENT
;
; PROCESS LABEL
;
	CALL	SLAB		;GET AND CHECK LABEL
	JC	OP5		;ERROR IN LABEL
	JZ	ERRD		;DUPLICATE LABEL
	CALL	LCHK		;CHECK CHARACTER AFTER LABEL
	JNZ	OP5		;ERROR IF NO BLANK
	MVI	C,LLAB		;LENGTH OF LABELS
	LXI	H,ABUF		;SET BUFFER ADDRESS
MLAB:	MOV	A,M		;FETCH NEXT CHARACTER
	STAX	D		;STORE IN SYMBOL TABLE
	INX	D
	INX	H
	DCR	C
	JNZ	MLAB
	XCHG
	SHLD	TABA		;SAVE TABLE ADDRESS FOR EQU
	LDA	ASPC+1		;FETCH PC (HIGH)
	MOV	M,A
	INX	H
	LDA	ASPC		;FETCH PC (LOW)
	MOV	M,A		;STORE IN TABLE
	LXI	H,NOLA
	INR	M		;INCREMENT NUMBER OF LABELS
;
; PROCESS OPCODE
;
OPC:	CALL	ZBUF		;ZERO WORKING BUFFER
	CALL	SBLK		;SCAN TO OPCODE
	JC	OERR		;FOUND CARRIAGE RETURN
	CALL	ALPS		;PLACE OPCODE IN BUFFER
	CPI	' '		;CHECK FOR BLANK AFTER OPCODE
	JC	OPCD		;CR AFTER OPCODE
	JNZ	OERR		;ERROR IF NO BLANK
	JMP	OPCD		;CHECK OPCODE
;
; THIS ROUTINE CHECKS THE CHARACTER AFTER A LABEL
; FOR A BLANK OR COLON
;
LCHK:	LHLD	PNTR
	MOV	A,M		;GET CHARACTER AFTER LABEL
	CPI	' '		;CHECK FOR BLANK
	RZ			;RETURN IF A BLANK
	CPI	':'		;CHECK FOR COLON
	RNZ
	INX	H
	SHLD	PNTR		;SAVE POINTER
	RET
;
; PROCESS ANY PSEUDO OPS THAT NEED TO BE IN PASS 1
;
PSU1:	CALL	SBLK		;SCAN TO OPERAND
	LDAX	D		;FETCH VALUE
	ORA	A		;SET FLAGS
	JZ	ORG1		;ORG OPCODE
	JM	DAT1		;DATA STATEMENT
	JPO	EQU1		;EQU OPCODE
	CPI	5
	JC	RES1		;RES OPCODE
	JNZ	EASS		;JUMP IF END
; DO DW PSEUDO/OP
ACO1:	MVI	C,2		;2 BYTE INSTRUCTION
	XRA	A		;GET A ZERO
	JMP	OCN1		;ADD VALUE TO PROGRAM COUNTER
; DO ORG PSUEDO OP
ORG1:	CALL	ASCN		;GET OPERAND
	LDA	OBUF		;FETCH ERROR INDICATOR
	CPI	' '		;CHECK FOR AN ERROR
	RNZ
	SHLD	ASPC		;STORE NEW ORIGIN
	LDA	IBUF		;GET FIRST CHARACTER
	CPI	' '		;CHECK FOR AN ERROR
	RZ			;NO LABEL
	JMP	EQUS		;CHANGE LABEL VALUE
; DO EQU PSUEDO-OP
EQU1:	CALL	ASCN		;GET OPERAND
	LDA	IBUF		;FETCH 1ST CHARACTER
	CPI	' '		;CHECK FOR LABEL
	JZ	ERRM		;MISSING LABEL
EQUS:	XCHG
	LHLD	TABA		;SYMBOL TABLE ADDRESS
	MOV	M,D		;STORE LABEL VALUE
	INX	H
	MOV	M,E
	RET
; DO DS PSEUDO-OP
RES1:	CALL	ASCN		;GET OPERAND
	MOV	B,H
	MOV	C,L
	JMP	RES21		;ADD VALUE TO PROGRAM COUNTER
;
; DO DB PSEUDO-OP
;
DAT1:	JMP	DAT2A
;
; PERFORM PASS 2 OF THE ASSEMBLER
;
PAS2:	LXI	H,OBUF+2		;SET OUTPUT BUFFER ADDRESS
	LDA	ASPC+1		;FETCH PC (HIGH)
	CALL	BINH+3		;CONVERT FOR OUTPUT
	INX	H
	LDA	ASPC		;FETCH PC(LOW)
	CALL	BINH+3		;CONVERT FOR OUTPUT
	INX	H
	SHLD	OIND		;SAVE OUTPUT ADDRESS
	CALL	ZBUF		;CLEAR BUFFER
	LXI	H,IBUF		;INITIALIZE LINE POINTER
PABL:	SHLD	PNTR		;SAVE POINTER
	MOV	A,M		;FETCH FIRST CHARACTER
	CPI	' '		;CHECK FOR LABEL
	JZ	OPC		;GET OPCODE
	CPI	'*'		;CHECK FOR COMMENT
	RZ			;RETURN IF COMMENT
	CALL	SLAB		;SCAN OFF LABEL
	JC	ERRL		;ERROR IN LABEL
	CALL	LCHK		;CHECK FOR A BLANK OR COLON
	JNZ	ERRL		;ERROR IF NOT A BLANK
	JMP	OPC
;
; PROCESS PSEUDO OPS FOR PASS2
;
PSU2:	LDAX	D
	ORA	A		;SET FLAGS
	JZ	ORG2		;ORG OPCODE
	JM	DAT2		;DATA OPCODE
	JPO	EQU2		;EQUATE PSEUDO-OP
	CPI	5
	JC	RES2		;RES OPCODE
	JNZ	EASS		;END OPCODE
; DO DW OPCODE
ACO2:	CALL	TYS6		;GET VALUE
	JMP	ACO1
; DO DS PSEUDO-OP
RES2:	CALL	ASBL		;GET OPERAND
	MOV	B,H
	MOV	C,L
	LHLD	BBUF+2		;FETCH STORAGE COUNTER
	DAD	B		;ADD VALUE
	SHLD	BBUF+2
RES21:	XRA	A		;GET A ZERO
	JMP	OCN2
; DO DB PSEUDO-OP
DAT2:	CALL	TY55		;GET OPERAND
DAT2A:	XRA	A		;MAKE ZERO
	MVI	C,1		;BYTE COUNT
	JMP	OCN1
;
; HANDLE EQUATES ON 2ND PASS
;
EQU2:	CALL	ASBL		;GET OPERAND INTO HL AND
				;  FALL INTO NEXT ROUTINE
;
; STORE CONTENTS OF HL AS HEX ASCII AT OBUF+2
;   ON RETURN, DE HOLDS VALUE WHICH WAS IN HL.
;
BINAD:	XCHG			;PUT VALUE INTO DE
	LXI	H,OBUF+2		;POINTER TO ADDR IN OBUF
	MOV	A,D		;STORE HI BYTE
	CALL	BINH+3
	INX	H
	MOV	A,E		;STORE LOW BYTE...
	CALL	BINH+3
	INX	H
	RET
; DO ORG PSEUDO-OP
ORG2:	CALL	ASBL		;GET NEW ORIGIN
	LDA	OBUF		;GET ERROR INDICATOR
	CPI	' '		;CHECK FOR AN ERROR
	RNZ			;DON?T MODIFY PC IF ERROR
	CALL	BINAD		;STORE NEW ADDR IN OBUF
	LHLD	ASPC		;FETCH PC
	XCHG
	SHLD	ASPC		;STORE NEW PC
	MOV	A,L
	SUB	E		;FORM DIFFERENCE OF ORIGINS
	MOV	E,A
	MOV	A,H
	SBB	D
	MOV	D,A
	LHLD	BBUF+2		;FETCH STORAGE POINTER
	DAD	D		;MODIFY
	SHLD	BBUF+2		;SAVE
	RET
;
; PROCESS 1 BYTE INSTRUCTIONS WITHOUT OPERANDS
;
TYP1:	CALL	ASTO		;STORE VALUE IN MEMORY
	RET
;
; PROCESS STAX AND LDAX INSTRUCTIONS
;
TYP2:	CALL	ASBL		;FETCH OPERAND
	CNZ	ERRR		;ILLEGAL REGISTER
	MOV	A,L		;GET LOW ORDER OPERAND
	ORA	A		;SET FLAGS
	JZ	TY31		;OPERAND = 0
	CPI	2		;OPERAND = 2
	CNZ	ERRR		;ILLEGAL REGISTER
	JMP	TY31
;
; PROCESS PUSH, POP, INX, DCX, DAD INSTRUCTIONS
;
TYP3:	CALL	ASBL		;FETCH OPERAND
	CNZ	ERRR		;ILLEGAL REGISTER
	MOV	A,L		;GET LOW ORDER OPERAND
	RRC			;CHECK LOW ORDER BIT
	CC	ERRR		;ILLEGAL REGISTER
	RAL			;RESTORE
	CPI	8
	CNC	ERRR		;ILLEGAL REGISTER
TY31:	RLC			;MULTIPLY BY 8
	RAL
	RAL
TY32:	MOV	B,A
	LDAX	D		;FETCH OPCODE BASE
	ADD	B		;FORM OPCODE
	CPI	118		;CHECK FOR MOV M,M
	CZ	ERRR		;ILLEGAL REGISTER
	JMP	TYP1
;
; PROCESS ACCUMULATOR, INR,DCR,MOV,RST INSTRUCTIONS
;
TYP4:	CALL	ASBL		;FETCH OPERAND
	CNZ	ERRR		;ILLEGAL REGISTER
	MOV	A,L		;GET LOW ORDER OPERAND
	CPI	8
	CNC	ERRR		;ILLEGAL REGISTER
	LDAX	D		;FETCH OPCODE BASE
	CPI	64		;CHECK FOR MOV INSTRUCTION
	JZ	TY41
	CPI	199
	MOV	A,L
	JZ	TY31		;RST INSTRUCTION
	JM	TY32		;ACCUMULATOR INSTRUCTION
	JMP	TY31		;INR, DCR
; PROCESS MOV INSTRUCTION
TY41:	DAD	H		;MULTIPLY OPERAND BY 8
	DAD	H
	DAD	H
	ADD	L		;FORM OPCODE
	STAX	D		;SAVE OPCODE
	CALL	MPNT
	CALL	ASCN
	CNZ	ERRR		;INCREMENT POINTER
	MOV	A,L
	CPI	8
	CNC	ERRR		;ILLEGAL REGISTER
	JMP	TY32
;
; PROCESS IMMEDIATE INSTRUCTIONS
; IMMEDIATE BYTE CAN BETWEEN -256 AND +255
; MVI INSTRUCTION IS A SPECIAL CASE AND CONTAINS
; 2 ARGUMENTS IN OPERAND
;
TYP5:	CPI	6		;CHECK FOR MVI
	CZ	TY56
	CALL	ASTO		;STORE OBJECT BYTE
TY55:	CALL	ASBL		;GET IMMEDIATE ARGUMENT
	INR	A
	CPI	2		;CHECK OPERAND FOR RANGE
	CNC	ERRV
	MOV	A,L
	JMP	TYP1
;
; FETCH 1ST ARG FOR MVI AND LXI INSTRUCTIONS
;
TY56:	CALL	ASBL		;FETCH ARG
	CNZ	ERRR		;ILLEGAL REGISTER
	MOV	A,L		;GET LOW ORDER ARGUMENT
	CPI	8
	CNC	ERRR		;ILLEGAL REGISTER
	DAD	H
	DAD	H
	DAD	H
	LDAX	D		;FETCH OPCODE BASE
	ADD	L		;FOR OPCODE
	MOV	E,A		;SAVE OBJECT BYTE
MPNT:	LHLD	PNTR		;FETCH POINTER
	MOV	A,M		;FETCH CHARACTER
	CPI	','		;CHECK FOR COMMA
	INX	H		;INCREMENT POINTER
	SHLD	PNTR
	JNZ	ERRS		;SYNTAX ERROR IF NO COMMA
	MOV	A,E
	RET
;
; PROCESS 3 BYTE INSTRUCTIONS
; LXI INSTRUCTION IS A SPECIAL CASE
;
TYP6:	CPI	1		;CHECK FOR LXI INSTRUCTION
	JNZ	TY6		;JUMP IF NOT LXI
	CALL	TY56		;GET REGISTER
	ANI	08H		;CHECK FOR ILLEGAL REGISTER
	CNZ	ERRR		;REGISTER ERROR
	MOV	A,E		;GET OPCODE
	ANI	0F7H		;CLEAR BIT IN ERROR
TY6:	CALL	ASTO		;STORE OBJECT BYTE
TYS6:	CALL	ASBL		;FETCH OPERAND
	MOV	A,L
	MOV	D,H
	CALL	ASTO		;STORE 2ND BYTE
	MOV	A,D
	JMP	TYP1
	RET
;
; THIS ROUTINE IS USED TO STORE OBJECT CODE PRODUCED
; BY THE ASSEMBLER DURING PASS 2 INTO MEMORY
;
ASTO:	LHLD	BBUF+2		;FETCH STORAGE ADDRESS
	MOV	M,A		;STORE OBJECT BYTE
	INX	H		;INCREMENT LOCATION
	SHLD	BBUF+2
	LHLD	OIND		;FETCH OUTPUT ADDRESS
	INX	H
	CALL	BINH+3		;CONVERT OBJECT BYTE
	SHLD	OIND
	RET
;
; GET HERE WHEN END PSEUDO-OP IS FOUND OR WHEN
; END-OF-FILE OCCURS IN SOURCE FILE.  CONTROL IS SET
; FOR EITHER PASS 2 OR ASSEMBLY TERMINATOR IF FINISHED
;
EASS:	LDA	PASI		;FETCH PASS INDICATOR
	ORA	A		;SET FLAGS
	JNZ	EOR		;JUMP IF FINISHED
	MVI	A,1		;PASS INDICATOR FOR 2ND PASS
	JMP	ASM3		;DO 2ND PASS
;
; THIS ROUTINE SCANS THROUGH A CHARACTER STRING UNTIL
; THE FIRST NON-BLANK CHARACTER IS FOUND
;
; ON RETURN, CARRY SET INDICATES A CARRIAGE RETURN
; AS  FIRST NON-BLANK CHARACTER.
;
SBLK:	LHLD	PNTR		;FETCH ADDRESS
SBL1:	MOV	A,M		;FETCH CHARACTER
	CPI	' '		;CHECK FOR BLANK
	RNZ			;RETURN IF NON-BLANK
SBL2:	INX	H		;INCREMENT
	SHLD	PNTR		;SAVE POINTER
	JMP	SBL1
;
; THIS ROUTINE IS USED TO CHECK THE CONDITION
; CODE NMEUMONICS FOR CONDITIONAL JUMPS, CALLS,
; AND RETURNS.
;
COND:	LXI	H,ABUF+1
	SHLD	ADDS
	MVI	B,2		;2 CHARACTERS
	CALL	COPC
	RET
;
; THE FOLLOWING IS THE OPCODE TABLE
;
OTAB:	DB	'ORG'
	DB	0
	DB	0
	DB	'EQU'
	DB	0
	DB	1
	DB	'DB'
	DB	0
	DB	0
	DB	-1 AND 0FFH
	DB	'DS'
	DB	0
	DB	0
	DB	3
	DB	'DW'
	DB	0
	DB	0
	DB	5
	DB	'END'
	DB	0
	DB	6
	DB	0
	DB	'HLT'
	DB	118
	DB	'RLC'
	DB	7
	DB	'RRC'
	DB	15
	DB	'RAL'
	DB	23
	DB	'RAR'
	DB	31
	DB	'RET'
	DB	201
	DB	'CMA'
	DB	47
	DB	'STC'
	DB	55
	DB	'DAA'
	DB	39
	DB	'CMC'
	DB	63
	DB	'EI'
	DB	0
	DB	251
	DB	'DI'
	DB	0
	DB	243
	DB	'NOP'
	DB	0
	DB	0
	DB	'XCHG'
	DB	235
	DB	'XTHL'
	DB	227
	DB	'SPHL'
	DB	249
	DB	'PCHL'
	DB	233
	DB	0
	DB	'STAX'
	DB	2
	DB	'LDAX'
	DB	10
	DB	0
	DB	'PUSH'
	DB	197
	DB	'POP'
	DB	0
	DB	193
	DB	'INX'
	DB	0
	DB	3
	DB	'DCX'
	DB	0
	DB	11
	DB	'DAD'
	DB	0
	DB	9
	DB	0
	DB	'INR'
	DB	4
	DB	'DCR'
	DB	5
	DB	'MOV'
	DB	64
	DB	'ADD'
	DB	128
	DB	'ADC'
	DB	136
	DB	'SUB'
	DB	144
	DB	'SBB'
	DB	152
	DB	'ANA'
	DB	160
	DB	'XRA'
	DB	168
	DB	'ORA'
	DB	176
	DB	'CMP'
	DB	184
	DB	'RST'
	DB	199
	DB	0
	DB	'ADI'
	DB	198
	DB	'ACI'
	DB	206
	DB	'SUI'
	DB	214
	DB	'SBI'
	DB	222
	DB	'ANI'
	DB	230
	DB	'XRI'
	DB	238
	DB	'ORI'
	DB	246
	DB	'CPI'
	DB	254
	DB	'IN'
	DB	0
	DB	219
	DB	'OUT'
	DB	211
	DB	'MVI'
	DB	6
	DB	0
	DB	'JMP'
	DB	0
	DB	195
	DB	'CALL'
	DB	205
	DB	'LXI'
	DB	0
	DB	1
	DB	'LDA'
	DB	0
	DB	58
	DB	'STA'
	DB	0
	DB	50
	DB	'SHLD'
	DB	34
	DB	'LHLD'
	DB	42
	DB	0
;	CONDITION	CODE	TABLE
	DB	'NZ'
	DB	0
	DB	'Z'
	DB	0
	DB	8
	DB	'NC'
	DB	16
	DB	'C'
	DB	0
	DB	24
	DB	'PO'
	DB	32
	DB	'PE'
	DB	40
	DB	'P'
	DB	0
	DB	48
	DB	'M'
	DB	0
	DB	56
	DB	0
;
; THIS ROUTINE IS USED TO CHECK A GIVEN OPCODE
; AGAINST THE LEGAL OPCODES IN THE OPCODE TABLE
;
COPC:	LHLD	ADDS
	LDAX	D		;FETCH CHARACTER
	ORA	A		;SET FLAGS
	JZ	COP1		;JUMP IF TERMINATION CHARACTER
	MOV	C,B
	CALL	SEAR
	LDAX	D
	RZ			;RETURN IF A MATCH
	INX	D		; NEXT STRING
	JMP	COPC		;CONTINUE SEARCH
COP1:	INR	A		;CLEAR ZERO FLAG
	INX	D		;INCREMENT ADDRESS
	RET
;
; THIS ROUTINE CHECKS THE LEGAL OPCODES IN BOTH PASS 1
; AND PASS 2.  IN PASS 1 THE PROGRAM COUNTER IS INCRE-
; MENTED BY THE CORRECT NUMBER OF BYTES.  AN ADDRESS IS
; ALSO SET SO THAT AN INDEXED JUMP CAN BE MADE TO
; PROCESS THE OPCODE FOR PASS 2.
;
OPCD:	LXI	H,ABUF		;GET ADDRESS
	SHLD	ADDS
	LXI	D,OTAB		;OPCODE TABLE ADDRESS
	MVI	B,4		;CHARACTER COUNT
	CALL	COPC		;CHECK OPCODE
	JZ	PSEU		;JUMP IF PSEUDO-OP
	DCR	B		;3-CHARACTER OPCODES
	CALL	COPC
	JZ	OP1
	INR	B		;4 CHARACTER OPCODES
	CALL	COPC
OP1:	LXI	H,TYP1		;TYPE 1 INSTRUCTIONS
OP2:	MVI	C,1		;1 BYTE INSTRUCTIONS
	JZ	OCNT
;
OPC2:	CALL	COPC		;CHECK FOR STAX, LDAX
	LXI	H,TYP2
	JZ	OP2
	CALL	COPC		;CHECK FOR PUSH,POP,INX
				; DCX AND DAD
	LXI	H,TYP3
	JZ	OP2
	DCR	B		;3 CHAR OPCODES
	CALL	COPC		;ACCUMULATOR INSTRUCTIONS,
				; INR, DCR, MOV, RST
	LXI	H,TYP4
	JZ	OP2
;
OPC3:	CALL	COPC		;IMMEDIATE INSTRUCTIONS
	LXI	H,TYP5
	MVI	C,2		;2 BYTE INSTRUCTIONS
	JZ	OCNT
	INR	B		;4 CHARACTER OPCODES
	CALL	COPC		;JMP, CALL, LIX, LDA, STA,
				; LHLD, SHLD OPCODES
	JZ	OP4
	CALL	COND		;CONDITIONAL INSTRUCTIONS
	JNZ	OERR		;ILLEGAL OPCODE
	ADI	192		;ADD BASE VALUE TO RETURN
	MOV	D,A
	MVI	B,3		;3 CHARACTER OPCODES
	LDA	ABUF		;FETCH FIRST CHARACTER
	MOV	C,A		;SAVE CHARACTER
	CPI	'R'		;CONDITIONAL RETURN
	MOV	A,D
	JZ	OP1
	MOV	A,C
	INR	D		;FORM CONDITIONAL JUMP
	INR	D
	CPI	'J'		;CONDITIONAL JUMP
	JZ	OPAD
	CPI	'C'		;CONDITIONAL CALL
	JNZ	OERR		;ILLEGAL OPCODE
	INR	D		;FORM CONDITIONAL CALL
	INR	D
OPAD:	MOV	A,D		;GET OPCODE
OP4:	LXI	H,TYP6
OP5:	MVI	C,3		;3 BYTE INSTRUCTION
OCNT:	STA	TEMP		;SAVE OPCODE
;
; CHECK FOR OPCODE ONLY CONTAINING THE CORRECT NUMBER OF
; CHARACTERS.  THUS ADDQ, SAY, WOULD GIVE AN ERROR
;
	MVI	A,ABUF AND 0FFH	;LOAD BUFFER ADDRESS
	ADD	B		;ADD LENGTH OF BUFFER
	MOV	E,A
	MVI	A,ABUF/256
	ACI	0		;GET HIGH ORDER ADDRESS
	MOV	D,A
	LDAX	D		;FETCH CHARACTER AFTER OPCODE
	ORA	A		;IT SHOULD BE ZERO
	JNZ	OERR		;OPCODE ERROR
	LDA	PASI		;FETCH PASS INDICATOR
OCN1:	MVI	B,0
	XCHG
OCN2:	LHLD	ASPC		;FETCH PROGRAM COUNTER
	DAD	B		;ADD IN BYTE COUNT
	SHLD	ASPC		;STORE PC
	ORA	A		;WHICH PASS?
	RZ			;RETURN IF PASS 1
	LDA	TEMP		;FETCH OPCODE
	XCHG
	PCHL
;
OERR:	LXI	H,ERRO		;GET ERROR ADDRESS
	MVI	C,3		;LEAVE 3 BYTES FOR PATCH
	JMP	OCN1-3
;
PSEU:	LXI	H,ABUF+4		;SET BUFFER ADDRESS
	MOV	A,M		;FETCH CHARACTER AFTER OPCODE
	ORA	A		;SHOULD BE A ZERO
	JNZ	OERR
	LDA	PASI		;FETCH PASS INDICATOR
	ORA	A
	JZ	PSU1
	JMP	PSU2
;
; THIS ROUTINE IS USED TO PROCESS LABELS.
; IT CHECKS TO SEE IF A LABEL IS IN THE SYMBOL TABLE
; OR NOT.  ON RETURN, Z=1 INDICATES A MATCH WAS FOUND
; AND H,L CONTAIN THE VALUE ASSOCIATED WITH THE LABEL.
; THE REGISTER NAMES A, B, C, D, E, H, L, P, AND S ARE
; PRE-DEFINED AND NEED NOT BE ENTERED BY THE USER.
; ON RETURN, C=1 INDICATES A LABEL ERROR.
;
SLAB:	CPI	'A'		;CHECK FOR LEGAL CHARACTER
	RC
	CPI	'Z'+1		;CHECK FOR ILLEGAL CHARACTER
	CMC
	RC			;RETURN IF ILLEGAL CHARACTER
	CALL	ALPS		;PLACE SYMBOL IN BUFFER
	LXI	H,ABUF		;SET BUFFER ADDRESS
	SHLD	ADDS		;SAVE ADDRESS
	DCR	B		;CHECK IF ONE CHARACTER
	JNZ	SLA1
; CHECK IF PREFEFINED REGISTER NAME
	INR	B		;SET B=1
	LXI	D,RTAB		;REGISTER NAME TABLE
	CALL	COPC		;CHECK NAME OF REGISTER
	JNZ	SLA1		;NOT A PREFEFINED REGIGTER
	MOV	L,A		;SET VALUE (HIGH)
	MVI	H,0
	JMP	SLA2
SLA1:	LDA	NOLA		;FETCH SYMBOL COUNT
	MOV	B,A
	LXI	D,SYMT		;SET SYMBOL TABLE ADDRESS
	ORA	A		;ARE THERE ANY LABELS?
	JZ	SLA3		;JUMP IF NO LABELS
	MVI	A,LLAB		;FETCH LENGTH OF LABEL
	STA	NCHR
	CALL	COMS		;CHECK TABLE
	MOV	C,H		;SWAP H AND L
	MOV	H,L
	MOV	L,C
SLA2:	STC			;SET CARRY
	CMC			;CLEAR CARRY
	RET			;RETURN
SLA3:	INR	A		;CLEAR ZERO FLAG
	ORA	A		;CLEAR CARRY
	RET
;
; PREDEFINE REGISTER VALUES IN THIS TABLE
;
RTAB:	DB	'A'
	DB	7
	DB	'B'
	DB	0
	DB	'C'
	DB	1
	DB	'D'
	DB	2
	DB	'E'
	DB	3
	DB	'H'
	DB	4
	DB	'L'
	DB	5
	DB	'M'
	DB	6
	DB	'P'
	DB	6
	DB	'S'
	DB	6
	DB	0		;END OF TABLE INDICATOR.
;
; THIS ROUTINE SCANS THE INPUT LINE AND PLACES TH
; OPCODES AND LABELS IN THE BUFFER.  THE SCAN TERMINATES
; WHEN A CHARACTER OTHER THAN 0-9 OR A-Z IS FOUND.
;
ALPS:	MVI	B,0		;SET COUNT
ALP1:	STAX	D		;STORE CHARACTER IN BUFFER
	INR	B		;INCREMENT COUNT
	MOV	A,B		;FETCH COUNT
	CPI	11		;MAXIMUM BUFFER SIZE
	RNC			;RETURN IF BUFFER FILLED
	INX	D		;INCREMENT BUFFER
	INX	H		;INCREMENT INPUT POINTER
	SHLD	PNTR		;SAVE LINE POINTER
	MOV	A,M		;FETCH CHARACTER
	CPI	'0'		;CHECK FOR ILLEGAL CHARACTERS
	RC
	CPI	'9'+1
	JC	ALP1
	CPI	'A'
	RC
	CPI	'Z'+1
	JC	ALP1
	RET
;
; THIS ROUTINE IS USED TO SCAN THROUGH THE INPUT LINE
; TO FETCH THE VALUE OF THE OPERAND FIELD.  ON RETURN,
; THE VALUE OF THE OPERAND IS CONTAINED IN REG?S H,L
;
ASBL:	CALL	SBLK		;GET 1ST ARGUMENT
ASCN:	LXI	H,0		;GET A ZERO
	SHLD	OPRD		;INITIALIZE OPERAND
	INR	H
	SHLD	OPRI-1		;INITIALIZE OPERAND INDICATOR
NXT1:	LHLD	PNTR		;FETCH SCAN POINTER
	DCX	H
	CALL	ZBUF		;CLEAR BUFFER
	STA	SIGN		;ZERO SIGN INDICATOR
NXT2:	INX	H		;INCREMENT POINTER
	MOV	A,M		;FETCH NEXT CHARACTER
	CPI	' '+1
	JC	SEND		;JUMP IF CR OR BLANK
	CPI	','		;FIELD SEPARATOR
	JZ	SEND
; CHECK FOR OPERATOR
	CPI	'+'		;CHECK FOR PLUS
	JZ	ASC1
	CPI	'-'		;CHECK FOR MINUS
	JNZ	ASC2
	STA	SIGN
ASC1:	LDA	OPRI		;FETCH OPERAND INDICATOR
	CPI	2		;CHECK FOR 2 OPERATORS
	JZ	ERRS		;SYNTAX ERROR
	MVI	A,2
	STA	OPRI		;SET INDICATOR
	JMP	NXT2
; CHECK FOR OPERANDS
ASC2:	MOV	C,A		;SAVE CHARACTER
	LDA	OPRI		;GET INDICATOR
	ORA	A		;CHECK FOR 2 OPERANDS
	JZ	ERRS		;SYNTAX ERROR
	MOV	A,C
	CPI	'$'		;LC EXPRESSION
	JNZ	ASC3
	INX	H		;INCREMENT POINTER
	SHLD	PNTR		;SAVE POINTER
	LHLD	ASPC		;FETCH LOCATION COUNTER
	JMP	AVAL
;CHECK FOR ASCII CHARACTERS
ASC3:	CPI	27H		;CHECK FOR SINGLE QUOTE
	JNZ	ASC5		;JUMP IF NOT QUOTE
	LXI	D,0		;GET A ZERO
	MVI	C,3		;CHARACTER COUNT
ASC4:	INX	H		;BUMP POINTER
	SHLD	PNTR		;SAVE
	MOV	A,M		;FETCH NEXT CHARACTER
	CPI	ASCR		;IS IT A CARRIAGE RETURN?
	JZ	ERAR		;ARGUMENT ERROR
	CPI	27H		;IS IT A QUOTE?
	JNZ	SSTR
	INX	H		;INCREMENT POINTER
	SHLD	PNTR		;SAVE
	MOV	A,M		;FETCH NEXT CHAR
	CPI	27H		;CHECK FOR 2 QUOTES IN A ROW
	JNZ	AVAL+1		;TERMINAL QUOTE
SSTR:	DCR	C		;CHECK COUNT
	JZ	ERAR		;TOO MANY CHARACTERS
	MOV	D,E
	MOV	E,A		;SET CHARACTER IN BUFFER
	JMP	ASC4
ASC5:	CPI	'0'		;CHECK FOR NUMERIC
	JC	ERAR		;ILLEGAL CHARACTER
	CPI	'9'+1
	JNC	ALAB
	CALL	NUMS		;GET NUMERIC VALUE
	JC	ERAR		;ARGUMENT ERROR
AVAL:	XCHG
	LHLD	OPRD		;FETCH OPERAND
	XRA	A		;GET A ZERO
	STA	OPRI		;STOR IN OPERAND INDICATOR
	LDA	SIGN		;GET SIGN INDICATOR
	ORA	A		;SET FLAGS
	JNZ	ASUB
	DAD	D		;FORM RESULT
ASC7:	SHLD	OPRD		;SAVE RESULT
	JMP	NXT1
ASUB:	MOV	A,L
	SUB	E
	MOV	L,A
	MOV	A,H
	SBB	D
	MOV	H,A
	JMP	ASC7
ALAB:	CALL	SLAB
	JZ	AVAL
	JC	ERAR		;ILLEGAL SYMBOL
	JMP	ERRU		;UNDEFINED SYMBOL
;
; GET HERE WHEN TERMINATING CHARACTER IS FOUND.
; CHECK FOR LEADING FIELD SEPARATOR
;
SEND:	LDA	OPRI		;FETCH OPERAND INDICATOR
	ORA	A		;SET FLAGS
	JNZ	ERRS		;SYNTAX ERROR
	LHLD	OPRD
SEN1:	MOV	A,H		;GET HIGH ORDER BYTE
	LXI	D,TEMP		;GET ADDRESS
	ORA	A		;SET FLAGS
	RET
;
; GET A NUMERIC VALUE WHICH IS EITHER HEXADECIMAL OR
; DECIMAL.  ON RETURN, CARRY SET INDICATES AN ERROR.
;
NUMS:	CALL	ALPS		;GET NUMERIC
	DCX	D
	LDAX	D		;GET LAST CHARACTER
	LXI	B,ABUF		;SET BUFFER ADDRESS
	CPI	'H'		;IS IT HEXADECIMAL?
	JZ	NUM2
	CPI	'D'		;IS IT DECIMAL
	JNZ	NUM1
	XRA	A		;GET A ZERO
	STAX	D		;CLEAR D FROM BUFFER
NUM1:	CALL	ADEC		;CONVERT DECIMAL VALUE
	RET
NUM2:	XRA	A		;GET A ZERO
	STAX	D		;CLEAR H FROM BUFFER
	CALL	AHEX
	RET
;
; PROCESS REGISTER ERROR
;
ERRR:	MVI	A,'R'		;GET INDICATOR
	LXI	H,0		;GET A ZERO
	STA	OBUF		;SET IN OUTPUT BUFFER
	RET
;
; PROCESS SYNTAX ERROR
;
ERRS:	MVI	A,'S'		;GET INDICATOR
	STA	OBUF		;STORE IN OUTPUT BUFFER
	LXI	H,0
	JMP	SEN1
;
; PROCESS UNDEFINED SYMBOL ERROR
;
ERRU:	MVI	A,'U'		;GET INDICATOR
	JMP	ERRS+2
;
; PROCESS VALUE ERROR
;
ERRV:	MVI	A,'V'		;GET INDICATOR
	JMP	ERRR+2
;
; PROCESS MISSING LABEL ERROR
;
ERRM:	MVI	A,'M'		;GET INDICATOR
	STA	OBUF		;STORE IN OUTPUT BUFFER
	CALL	AOU1		;DISPLAY ERROR
	RET
;
;PROCESS ARGUMENT ERROR
;
ERAR:	MVI	A,'A'		;GET INDICATOR
	JMP	ERRS+2
;
; PROCESS OPCODE ERROR
; STORE 3 BYTES OF ZERO IN OBJECT CODE TO PROVIDE
; FOR A PATCH
;
ERRO:	MVI	A,'O'		;GET INDICATOR
	STA	OBUF		;STORE IN OUTPUT BUFFER
	LDA	PASI		;FETCH PASS INDICATOR
	ORA	A		;WHICH PASS
	RZ			;RETURN IF PASS 1
	MVI	C,3		;NEED 3 BYTES
ERO1:	XRA	A		;GET A ZERO
	CALL	ASTO		;PUT IN LISTING AND MEMORY
	DCR	C
	JNZ	ERO1
	RET
;
; PROCESS LABEL ERROR
;
ERRL:	MVI	A,'L'		;GET INDICATOR
	JMP	ERRO+2
;
; PROCESS DUPLICATE LABEL ERROR
;
ERRD:	MVI	A,'D'		;GET INDICATOR
	STA	OBUF
	CALL	AOUT
	JMP	OPC
;
; THIS ROUTINE SETS OR CLEARS BREAKPOINTS
;
BREAK:	LDA	ABUF		;CHECK FOR AN ARG
	ORA	A
	JZ	CLRB		;IF NO ARGUMENT, GO CLEAR BREAKPOINT
	MVI	D, NBR		;ELSE GET NUMBER OF BREAKPOINTS
	LXI	H,BRT		;AND ADDR OF TABLE
B1:	MOV	A,M		;GET HI BYTE OF ENTRY
	INX	H
	MOV	B,M		;GET LOW BYTE OF ENTRY
	ORA	B		;CHECK FOR EMPTY ENTRY
	JZ	B2		;BRANCH IF EMPTY
	INX	H		;ELSE GO ON TO NEXT ENTRY
	INX	H
	DCR	D		;BUMP COUNT
	JNZ	B1		;AND TRY AGAIN
	JMP	WHAT		;OOPS NO ROOM
B2:	DCX	H
	XCHG
	LHLD	BBUF		;GET ADDRESS
	XCHG			;IN D,E
	MOV	A,D		;CHECK FOR ADDR > 11D
	ORA	A
	JNZ	B3
	MOV	A,E
	CPI	11
            JC	WHAT		;OOPS, TOO LOW
B3:	MOV	M,D		;SAVE ADDRESS
	INX	H
	MOV	M,E
	INX	H
	LDAX	D		;PICK UP INSTRUCTION
	MOV	M,A		;SAVE IT
	MVI	A,0CFH		;RST 1 INSTRUCTION
	STAX	D
	MVI	A,0C3H		;SET UP LO MEMORY
	STA	8		;WITH A JUMP TO BREAKPOINT
	LXI	H,BRKP
	SHLD	9
	RET			;THEN RETURN
;
; THIS ROUTINE CLEARS ALL BREAKPOINTS
;
CLRB:	LXI	H,BRT		;GET TABLE ADDRESS
	MVI	B,NBR		;GET NUMBER OF BREAKPOINTS
CLBL:	XRA	A		;GET A ZERO
	MOV	D,M		;GET HI-BYTE OF ENTRY
	MOV	M,A
	INX	H
	MOV	E,M		;GET LO-BYTE OF ENTRY
	MOV	M,A
	INX	H
	MOV	B,M		;GET INST BYTE
	INX	H
	MOV	A,D		;WAS THIS A NULL ENTRY
	ORA	E
	JZ	CL2		;BRANCH IF IT WAS
	MOV	A,B
	STAX	D		;ELSE PLUG INST BACK IN
CL2:	DCR	B		;BUMP COUNT
	JNZ	CLBL		;GO DO NEXT ONE
	RET
;
; COME HERE WHEN WE HIT A BREAKPOINT
;
BRKP:	SHLD	HOLD+8		;SAVE H,L
	POP	H		;GET PC
	DCX	H		;ADJUST IT
	SHLD	HOLD+10		;SAVE IT
	PUSH	PSW		;SAVE FLAGS
	POP	H		;GET THEM INTO H,L
	SHLD	HOLD		;NOW STORE THEM FOR USER
	LXI	H,0
	DAD	SP		;GET STACK POINTER
	LXI	SP,HOLD+8	;SET STACK POINTER AGAIN
	PUSH	H		;SAVE OLD SP
	PUSH	D		;SAVE D,E
	PUSH	B		;SAVE B,C
	CMA			;COMPLEMENT ACCUMULATOR
	OUT	0FFH		;DISPLAY IT IN LIGHTS
	LXI	SP,AREA+18	;SET SP AGAIN
	LHLD	HOLD+10		;GET PC
	XCHG			;INTO D,E
	LXI	H,BRT		;GET ADDR OF TABLE
	MVI	B,NBR		;AND NUMBER OF ENTRIES
BL1:	MOV	A,M		;GET AN ENTRY FROM THE TABLE
	INX	H
	CMP	D		;DOES IT MATCH?
	JNZ	BL2		;BRANCH IF NOT
	MOV	A,M		;ELSE GET NEXT BYTE
	CMP	E		;CHECK IT
	JZ	BL3		;IT MATCHES!
BL2:	INX	H		;BUMP AROUND THIS ENTRY
	INX	H
	DCR	B		;BUMP COUNT
	JZ	WHAT		;NOT IN OUR TABLE
	JMP	BL1
;
BL3:	INX	H
	MOV	A,M		;GET INSTR BYTE
	STAX	D		;PUT IT BACK
	XRA	A		;CLEAR ENTRY IN TABLE
	DCX	H
	MOV	M,A
	DCX	H
	MOV	M,A
	CALL	CRLF		;RESTORE THE CARRIAGE
	LDA	HOLD+11		;GET HI-BYTE OF PC
	CALL	HOUT		;TYPE IT
	LDA	HOLD+10		;GET LO-BYTE OF PC
	CALL	HOUT		;TYPE IT
	LXI	H,BMES		;TELL USER WHAT IT IS
	CALL	SCRN
	JMP	EOR		;GO BACK TO COMMAND LEVEL
;
BMES:	DB	' BREAK',13
;
; THIS ROUTINE PROCEEDS FROM A BREAKPOINT
;
PROC:	LDA	ABUF		;CHECK FOR ARG
	ORA	A
	JZ	P1		;JUMP IF NO ARG
	LHLD	BBUF		;ELSE GET ARG
	SHLD	HOLD+10		;PLUG IT INTO PC SLOT
P1:	LXI	SP,HOLD		;SET SP TO POINT AT REG?S
	POP	PSW		;RESTORE PSW
	POP	B		;RESTORE B,C
	POP	D		;RESTORE D,E
	POP	H		;GET OLD SP
	SPHL			;RESTORE IT
	LHLD	HOLD+10		;GET PC
	PUSH	H		;PUT IT ON STACK
	LHLD	HOLD+8		;RESTORE H,L
	RET			;AND PROCEED
;
; SYSTEM RAM
;
	ORG	1000H
;
; DEFINE BREAKPOINT REGION
;
NBR	EQU	8		;NUMBER OF BREAKPOINTS
HOLD	DS	12		;REGISTER HOLD AREA
BRT	DS	3*NBR		;BREAKPOINT TABLE
;
; FILE AREA PARAMETERS
;
MAXFIL	EQU	6
NMLEN	EQU	5
FELEN	EQU	NMLEN+8
FILE0	DS	NMLEN
BOFP	DS	2
EOFP	DS	2
MAXL	DS	4
FILTB	DS	(MAXFIL-1)*FELEN
INSP	DS	2
DELP	EQU	INSP
ASCR	EQU	13
HCON	DS	2
ADDS	EQU	HCON
FBUF	DS	NMLEN
FREAD	DS	2
FEF	DS	1
FOCNT	EQU	FEF
ABUF	DS	12
BBUF	DS	4
SCNT	DS	1
DCNT	DS	1
NCOM	EQU	11
TABA	DS	2
ASPC	DS	2
PASI	DS	1
NCHR	DS	1
PNTR	DS	2
NOLA	DS	1
SIGN	DS	1
OPRD	DS	2
OPRI	DS	1
TEMP	DS	1
APNT	EQU	INSP
AERR	EQU	SCNT
OIND	DS	2
LLAB	EQU	5
AREA	DS	18
OBUF	DS	16
	DS	5
IBUF	DS	83
SWCH	EQU	0FFH
SYMT	EQU	$
	END
