title System overlay RAM used by ROM software.   (C) 1983 By NLS
.comment %
########################################################
##                                                    ##
##      KAYPRO 10 System                              ##
##                                                    ##
##      By G. Ohnysty                                 ##
##                                                    ##
##      System overlay RAM used by ROM software       ##
##                                                    ##
##      Copyright (C) 1983 By Non-Linear Systems, Inc ##
##      No warranty is made, expressed or implied.    ##
##                                                    ##
########################################################
##      Date: 04/14/83                    [01]        ##
########################################################
%
.z80

extrn	$pixon, $pixoff, $linon, $linoff

esc	equ	1BH		; ascii escape
vidout	equ	45H		; video output

	jp	wrtrcov		; write error handler
	jp	rdrcov		; read error handler
	jp	$pixon		; pixel on
	jp	$pixoff		; pixel off
	jp	$linon		; draw line
	jp	$linoff		; erase line
	rept	9		; <reserved>
	jp	no.op
	endm


wrtrcov:call	print
	db	esc,'B','7',esc,'B','6',esc,'=',56,32,18H
	db	'Write Fault on hard disk!'
	db	esc,'C','6',0
	ld	a,0ffH
	or	a
	ret

rdrcov:	call	print
	db	esc,'B','7',esc,'B','6',esc,'=',56,32,18H
	db	'Read Fault on hard disk!'
	db	esc,'C','6',0
	ld	a,0ffH
	or	a
	ret


no.op:	or	a		; a no op is [or a, ret]
	ret

print:	ex	(sp),hl		; hl points to text
	ld	a,(hl)
	inc	hl
	ex	(sp),hl
	or	a		; string end with 0
	ret	z
	ld	c,a
	call	vidout		; rom video output routine
	jr	print

	db	0
	end