.model large,c
.code
public	scan
scan	proc	far

	mov	ax,0a000h
	mov	es,ax

	mov	cx,4
d2:	push	cx

	dec	cl

	mov	dx,3ceh

	mov	al,4
	mov	ah,cl
	out	dx,ax

	mov	dx,3c4h		;write	pl
   	mov	al,2
	mov	ah,1b


	shl	ah,cl
	out	dx,ax

	mov	bx,0
	mov	cx,40*349
do1:    mov	ax,es:[bx]
	xor	es:[bx]+80,ax
	inc	bx
	inc	bx
	loop	do1

	pop	cx
	loop	d2

	ret
scan	endp
end


