CR	EQU	0DH
LF	EQU	0AH
;
; ISIS CALLS
;
OPEN	EQU	0
CLOSE	EQU	1
READ	EQU	3
WRITE	EQU	4
EXIT	EQU	9
ERROR	EQU	12
;

TTYI	EQU	0F4H
TTYO	EQU	0F4H
TTYS	EQU	0F5H
TTYC	EQU	0F5H
;
TRDY	EQU	00000001B
RRDY	EQU	00000010B
;
DTR	EQU	00000010B
;
	EXTRN	ISIS
	EXTRN	CO
	EXTRN	CI
;
	CSEG
;
HELP:	LXI	SP,STK+4
;
		LXI	H,HELPMSG-1
HELP0:
		INX		H
		MOV		A,M
		CPI		0
		JZ		LISTEN
		MOV		C,M
		CALL	CRTOUT
;		CALL	CI
;		ANI		07FH
;		CPI		CR
;		JZ		ABORT
		JMP		HELP0
;
LISTEN:
		CALL	CRTIN
		ANI		07FH
		MOV		C,A		; COPY TO C
		CPI		03EH	; IS IT ">"?
		JNZ		NOTEND
		LDA		BUFFER	; GET LAST CHAR
		CPI		05CH	; WAS IT "\"?
		JZ		DONE
NOTEND:
		MOV		A,C		;
		STA		BUFFER	; SAVE AS LAST CHAR
		CALL	CO		; AND PRINT IT ON SCREEN
		JMP		LISTEN
;
HELPMSG:	DB	'HELP',CR,0
ERRMSG:		DB	CR,'USER ABORTED',CR,LF,0
;
ABORT:
		LXI	H,ERRMSG-1
ABORT0:
		INX	H
		MOV	A,M
		CPI	0
		JZ	DONE
		MOV	C,M
		CALL	CO
		JMP	ABORT0
;
DONE:
		MVI		C,CR	; FINISH OFF WITH CF, LF
		CALL	CO
		MVI		C,LF
		CALL	CO
		MVI		C,EXIT
		LXI		D,XBLK
		CALL	ISIS
;
	DSEG

XBLK:	DW	STATUS
EBLK:
STATUS:	DS	2
		DW	STATUS
;
BUFFER:	DS	128
;
STK:	DS	4
;
	CSEG
;
CRTOUT:
		IN	0F7H
		ANI	TRDY
		JZ	CRTOUT
		MOV	A,C
		OUT	0F6H
		RET
;
CRTIN:
		IN	0F7H
		ANI	RRDY
		JZ	CRTIN
		IN	0F6H
		RET
;
END	HELP