From: John Tsiombikas <nuclear@member.fsf.org>
Date: Wed, 14 Sep 2022 21:48:46 +0000 (+0300)
Subject: xor not right
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=commitdiff_plain;h=c4e4cf9bda70eed128e224e914b8abf6ae334a5d;hp=71180a72d4e205696eb3b0f6db03a56c65a845b5;p=a2gs_xortest

xor not right
---

diff --git a/xortest.s b/xortest.s
index b876059..ce89274 100644
--- 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