xor not right

diff --git a/xortest.s b/xortest.s
index b876059..ce89274 100644 (file)
--- a/xortest.s
+++ b/xortest.s
@@ -16,7 +16,7 @@ fillrest
        stal $e19d00,x
        inx
        inx
-       cpx #$300
+       cpx #$100
        bne fillrest
        
        lda #$0000
@@ -38,23 +38,29 @@ cmap        pha
        bne cmap
 
 YVAL   = 0
-COLIDX = 1
+TMPVAL = 1
 
        sep #$20        ; accum 8bit
        ldx #0          ; fb index
        stz YVAL
-yloop  lda YVAL
-       and #$f
-       sta COLIDX
+yloop  ldy #0000       ; column/2 on Y reg
+xloop  tya
        asl
+       and #$0f
+       sta TMPVAL      ; save first pixel X coordinate
+       inc             ; increment by 1 for the next pixel
+       eor YVAL
+       asl             ; move next pixel value to high nibble
        asl
        asl
        asl
-       ora COLIDX
-       ldy #160        ; 160 bytes across
-xloop  stal FB_BASE,x
+       ora TMPVAL      ; first pixel X -> low nibble
+       eor YVAL
+
+       stal FB_BASE, x ; write the pixel pair
        inx
-       dey
+       iny
+       cpy #160
        bne xloop
        inc YVAL
        lda YVAL