@@ -23,24 +23,25 @@ static Uint8 blending[4][16] = {

 	{2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2}};

 static void

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

+screen_pixel(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;

-		}

-	}

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

+		return;

+	layer->pixels[x + y * p->width] = color;

 }

 static void

 screen_fill(UxnScreen *p, Layer *layer, Uint16 x1, Uint16 y1, Uint16 x2, Uint16 y2, Uint8 color)

 {

-	int v, h;

-	for(v = y1; v < y2; v++)

-		for(h = x1; h < x2; h++)

-			screen_write(p, layer, h, v, color);

+	int x, y;

+	if(x2 >= p->width) x2 = p->width;

+	if(y2 >= p->height) y2 = p->height;

+	if(x1 >= x2 || y1 >= y2)

+		return;

+	for(y = y1; y < y2; y++)

+		for(x = x1; x < x2; x++)

+			layer->pixels[x + y * p->width] = color;

+	layer->changed = 1;

 }

 static void

@@ -52,13 +53,14 @@ screen_blit(UxnScreen *p, Layer *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8

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

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

 			if(opaque || ch)

-				screen_write(p,

+				screen_pixel(p,

 					layer,

 					x + (flipx ? 7 - h : h),

 					y + (flipy ? 7 - v : v),

 					blending[ch][color]);

 		}

 	}

+	layer->changed = 1;

 }

 void

@@ -137,7 +139,8 @@ screen_deo(Uint8 *ram, Uint8 *d, Uint8 port)

 			Uint8 xflip = d[0xe] & 0x10, yflip = d[0xe] & 0x20;

 			screen_fill(&uxn_screen, layer, xflip ? 0 : x, yflip ? 0 : y, xflip ? x : uxn_screen.width, yflip ? y : uxn_screen.height, d[0xe] & 0x3);

 		} else {

-			screen_write(&uxn_screen, layer, x, y, d[0xe] & 0x3);

+			screen_pixel(&uxn_screen, layer, x, y, d[0xe] & 0x3);

+			layer->changed = 1;

 			if(d[0x6] & 0x1) POKE2(d + 0x8, x + 1); /* auto x+1 */

 			if(d[0x6] & 0x2) POKE2(d + 0xa, y + 1); /* auto y+1 */

 		}