cc65/libsrc/vic20/color.s

;
; Ullrich von Bassewitz, 06.08.1998
; Adapted for Vic20 by Steve Schmidtke 05.08.2002
;
; unsigned char __fastcall__ textcolor (unsigned char color);
; unsigned char __fastcall__ bgcolor (unsigned char color);
; unsigned char __fastcall__ bordercolor (unsigned char color);
;


 	.export		_textcolor, _bgcolor, _bordercolor
	.importzp	tmp1

	.include	"vic20.inc"



.code

_textcolor:
	ldx	CHARCOLOR	; get old value
 	sta	CHARCOLOR	; set new value
	txa
	rts


_bgcolor:
	asl
	asl
	asl
	asl
	sta	tmp1
	sei	    		; don't want anything messing around while we update
	lda	VIC_COLOR	; get old value
	and	#$0F
	tax
	ora	tmp1
	sta	VIC_COLOR	; set new value
	cli
	txa
	lsr
	lsr
	lsr
	lsr
	rts


_bordercolor:
	and	#$07
	sta	tmp1
	sei	    		; don't want anything messing around while we update
       	lda    	VIC_COLOR   	; get old value
	and	#$F8
	tax
	ora	tmp1
	sta	VIC_COLOR	; set new value
	cli
	txa
	rts