;
; Program: ERROR3
; Author: Richard Conn
; Version: 1.0
; Date: 5 Mar 84
;
version	equ	10

;
;	This error handler displays the name of the COM file which was
; not found and then flushes the command line, returning control to the
; user.
;
;	This program is transportable from one ZCPR3 system to another
; provided it is reassembled with the correct address for the ZCPR3
; Environment Descriptor (Z3ENV) or DDT is used to patch this address
; (which is the first two bytes after the opening JMP).  If an external
; ZCPR3 Environment Descriptor is not available, one will have to be
; provided by setting the Z3ENV equate to 0 and providing SYSENV.LIB in
; the current directory at assembly time.
;

;
; Equates for Key Values
;
z3env	SET	0f400h	;address of ZCPR3 environment
cmtch	equ	';'	;comment character
cr	equ	0dh
lf	equ	0ah

;
; External Z3LIB and SYSLIB Routines
;
	ext	z3init
	ext	print,pstr,codend,moveb
	ext	erradr,puter1,puterc		;Error Handler Routines
	ext	getefcb,getcl1,qerror		;Z3 Messages et al

;
; Environment Definition
;
	if	z3env ne 0
;
; External ZCPR3 Environment Descriptor
;
	jmp	start
	db	'Z3ENV'	;This is a ZCPR3 Utility
	db	1	;External Environment Descriptor
z3eadr:
	dw	z3env
start:
	lhld	z3eadr	;pt to ZCPR3 environment
;
	else
;
; Internal ZCPR3 Environment Descriptor
;
	MACLIB	Z3BASE.LIB
	MACLIB	SYSENV.LIB
z3eadr:
	jmp	start
	SYSENV
start:
	lxi	h,z3eadr	;pt to ZCPR3 environment
	endif

;
; Start of Program -- Initialize ZCPR3 Environment
;
	call	z3init	;initialize the ZCPR3 Environment
;
; Determine if Program Invoked as an Error Handler or By the User
;
	call	qerror	;error?
	jz	handler	;handle error
;
; Invoked by the User, so Install as an Error Handler
;
	call	getefcb		;pt to external FCB
	jz	start1		;proceed if external FCB not available
;
; Make Name Invoked by User the Name of the Error Handler
;
	inx	h		;pt to first char
	lxi	d,ername	;pt to name of error handler message
	mvi	b,8		;at most 8 bytes
	call	moveb		;copy into buffer
;
; Make Command Line in Buffer the Error Handler
;
start1:
	lxi	h,ername	;make name in buffer the error handler
	call	puterc		;set command
	mvi	a,0ffh		;set error code
	call	puter1		;set message
	call	print
	db	'ERROR3, Version '
	db	(version/10)+'0','.',(version mod 10)+'0'
	db	cr,lf,' Error Handler Installed',0
	ret
;
; Handle Error
;
handler:
	call	erradr		;get address of error line
	xchg			;HL pts to free area, DE pts to error line
	call	codend		;get ptr to free area
;
; Extract Bad Command and Store It in Memory Starting at CODEND
;	DE pts to bad command, HL pts to location to store it at
;
savebad:
	ldax	d		;get next char
	mov	m,a		;put it
	ora	a		;done?
	jz	sbad1
	cpi	cmtch		;check for comment
	jz	sbad1
	cpi	' '		;check for space
	jz	sbad1
	inx	h		;pt to next
	inx	d
	jmp	savebad
;
; Set ending 0 in bad command buffer and print error message and command
;
sbad1:
	mvi	m,0		;store ending zero
	call	print
	db	' File ',0
	call	codend		;pt to name
	call	pstr
	call	print
	db	'.COM Not Found',0
	call	getcl1		;pt to command line buffer
	lxi	d,4		;pt to first char position
	push	h		;save current ptr
	dad	d
	mvi	m,0		;zero command line
	xchg			;DE pts to command line
	pop	h
	mov	m,e		;store address
	inx	h
	mov	m,d
	ret

;
; Buffers
;
ername:
	db	'ERROR3  ',0	;name of error handler

	end