cc65/libsrc/c128/color.s

;
; Ullrich von Bassewitz, 06.08.1998
;
; 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
        .import         return0

	.include	"c128.inc"


_textcolor:
	bit	MODE		; Check 80/40 column mode
       	bmi     @L1 		; Jump if 80 columns

; 40 column mode

        ldx     CHARCOLOR       ; Get the old color
        sta     CHARCOLOR       ; Set the new color
        txa                     ; Old color -> A
        ldx     #$00            ; Load high byte
        rts

; 80 column mode

@L1:    tax                     ; Move new color to X
        lda     CHARCOLOR       ; Get old color + attributes
        and     #$F0            ; Keep old attributes
	ora     $CE5C,x		; Translate VIC color -> VDC color
        ldx     CHARCOLOR       ; Get the old color
        sta     CHARCOLOR       ; Set the new color + old attributes
        txa                     ; Old color -> A
        and     #$0F            ; Mask out attributes
        ldx     #$00            ; Load high byte

; translate vdc->vic colour

vdctovic:
       	ldy	#16
@L2:    cmp	$CE5C-1,y
        beq	@L3
        dey
        bne     @L2
@L3:	tya
	rts


_bgcolor:
        bit     MODE
        bmi     @L1

; 40 column mode

	ldx	VIC_BG_COLOR0	; get old value
	sta	VIC_BG_COLOR0	; set new value
	txa
        ldx     #$00
	rts

; 80 column mode

@L1:    tax                     ; Move new color to X
       	lda     $CE5C,x		; Translate VIC color -> VDC color
	pha
	ldx	#26
       	jsr    	$CDDA		; Read vdc register 26
	jsr	vdctovic
	tay
	pla
	ldx	#26
       	jsr    	$CDCC		; Write vdc register 26
	tya
        ldx     #$00
	rts


_bordercolor:
        bit     MODE
        bmi     @L1

; 40 column mode

       	ldx    	VIC_BORDERCOLOR	; get old value
	sta	VIC_BORDERCOLOR	; set new value
	txa
        ldx     #$00
	rts

; 80 column mode

@L1:    jmp     return0