ld	de,plotSScreen
	ex	de,hl
	ld	a,e
	or	%11111000
	ld	bc,64*256+$80
	rlc	c
	inc	a
	jr	nz,$-3
	srl	e
	srl	e
	srl	e
	ld	d,a
	add	hl,de
	ld	a,e
	ld	e,12
	cp	e
	ret	nc
	ld	a,(hl)
	or	c
	ld	(hl),a
	add	hl,de
	djnz	$-4
	ret