soft80_kplot.s

//
// Groepaz/Hitmen, 12.10.2015
//
// lowlevel kplot function for the soft80 implementation
//
#import "soft80.inc"

soft80_kplot:
        bcs     getpos

        stx     CURS_Y
        sty     CURS_X

        sei
        lda     $01
        pha
        lda     #$34                            // enable RAM under I/O
        sta     $01

        // calc pointer to bitmap
        lda     soft80_bitmapylo,x
        clc
        adc     soft80_bitmapxlo,y
        sta     SCREEN_PTR
        lda     soft80_bitmapyhi,x
        adc     soft80_bitmapxhi,y
        sta     SCREEN_PTR+1

        tya
        and     #1
        sta     soft80_internal_cursorxlsb

        // calc pointer to vram
        tya
        lsr     //a

        clc
        adc     soft80_vramlo,x
        sta     CRAM_PTR
        lda     #0
        adc     soft80_vramhi,x
        sta     CRAM_PTR+1

        pla
        sta     $01
        cli

getpos:
        ldx     CURS_Y
        ldy     CURS_X
        rts