@@ -28,12 +28,13 @@ static Uint32 palette_mono[] = {

 static void

 screen_write(UxnScreen *p, Layer *layer, Uint16 x, Uint16 y, Uint8 color)

 {

-	if(x < p->width && y < p->height) {

-		Uint32 i = x + y * p->width;

-		if(color != layer->pixels[i]) {

-			layer->pixels[i] = color;

-			layer->changed = 1;

-		}

+	Uint32 i;

+	if(x > p->width || y > p->height)

+		return;

+	i = x + y * p->width;

+	if(color != layer->pixels[i]) {

+		layer->pixels[i] = color;

+		layer->changed = 1;

 	}

 }

@@ -42,7 +43,7 @@ screen_blit(UxnScreen *p, Layer *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8

 {

 	int v, h, opaque = (color % 5) || !color;

 	for(v = 0; v < 8; v++) {

-		Uint16 c = sprite[v] | (twobpp ? sprite[v + 8] : 0) << 8;

+		Uint16 c = sprite[v] | (twobpp ? (sprite[v + 8] << 8) : 0);

 		for(h = 7; h >= 0; --h, c >>= 1) {

 			Uint8 ch = (c & 1) | ((c >> 7) & 2);

 			if(opaque || ch)

@@ -179,7 +180,7 @@ screen_deo(Uint8 *ram, Uint8 *d, Uint8 port)

 		n = d[0x6] >> 4;

 		dx = (d[0x6] & 0x01) << 3;

 		dy = (d[0x6] & 0x02) << 2;

-		if(addr > 0x10000 - ((n + 1) << (3 + twobpp)))

+		if(addr > 0xfff0)

 			return;

 		for(i = 0; i <= n; i++) {

 			screen_blit(&uxn_screen, layer, x + dy * i, y + dx * i, &ram[addr], d[0xf] & 0xf, d[0xf] & 0x10, d[0xf] & 0x20, twobpp);