org 30h
	.z80


start:  ld	sp,30h
	ld	hl,begin
	ld	de,30h
	ld	bc,ecode - begin
	ldir				

begin:	ld	a,1
	out	(41h),a			;turn DJ off
	call	prstart
	ld	c,0			;segment counter
	ld	iy,0ffh			;report map pointer
	ld	a,'A'			;pass 1 = A
	ld	(iy),a
	inc	iy			;now point to map
	ld	ix,mapram + 2
	ld	b,0			;test pattern
	call	initmap

;********************************************************
;*    Loop0 - updates the segment under test for 1 Mb   *
;*            of main memory (c = 0ffh).		*
;*    Loop1 - Checks memory 4 Kb with character in b 	*
;*            and it's complement.			*
;*    Loop2 - goes back and checks again--checking for	*
;*            for refresh problems			*
;*							*
;******************************************************** 

loop0:  ld	hl,1000h		;memory counter
	ld	(ix),c			;segment pointer
	ld	a,b

loop1:	ld	(hl),a
	cp	(hl)
	jr	nz,error
	cpl	
	ld	(hl),a
	cp	(hl)
	jr	nz,error
	inc	hl
	bit	1,h
	jr	z,loop1	
	ld	hl,1000h	       ;check again for refresh
	ld	a,b
loop2:	cp	(hl)
	jr	nz,error
	cpl
	inc	hl
	bit	1,h
	jr	z,loop2
	ld	a,'G'
	call	message
	inc	c
	jr	z,prnmap		;print report if done
	jr	loop0			;next segment


error:	ld	a,'X'
	call	message
	inc	c
	jr	z,prnmap		;print report if done
	jr	loop0			;next segment

message:
	push	af
	ld	a,(iy)			;get old segment result
	inc	iy			;next map entry
	cp	'X'			;was it bad??
	ret	z			;leave alone if yes
	pop	a
	ld	(iy),a			;update the map
	ret

initmap:
	ld	d,0ffh			;byte count
initlp: ld	(iy),b			;null the message ram
	inc	iy
	dec	d
	jr	nz,initlp
	ret 

prnmap:	ld	iy,0ffh			;begining report buffer
	ld	d,0h			;byte count
	ld	l,0fh			;16 bytes per line
	call	passprn

pmap0:	ld	a,(iy)			;get the results
	ld	c,a			;print character in c
	call	conout			;print it
	inc	iy			;next segment report
	dec	l
	call	z,crlf			;16 bytes per line
	dec	d		
	jr 	nz,pmap0		;255 entries

newpas: ld	a,b
	rrc
	ld	b,a
	ld	c,0			;next pass
	ld	iy,0ffh	
	ld	a,(iy)
	inc	a
	ld	(iy),a			;increment the pass
	jr 	loop0


;  routine prints the pass number

passprn:
	call	crlf
	call	crlf
	ld	a,(iy)			;get the pass number
	inc	iy
	ld	c,a
	call	conout
	

;  Print a carriage return/line feed

crlf:	ld	c,ACR
	call	conout
	ld	c,ALF

;  Console output routine for Mult I/O or WB I/O
	
conout: ld	a,grp1
	out	(grpctl),a
wait:	in	a,(lsr)
	and	thbe
	jr	nz,wait
	ld	a,c
	out	(tbr),a
	ret


ecode	equ	$

	end