diff --git a/src/ppu.c b/src/ppu.c
index dcf4e9c..dde934e 100644
--- a/src/ppu.c
+++ b/src/ppu.c
@@ -64,11 +64,12 @@ rgb565(u32 rgba) {
 
 void
 ppu_pixel(u8 *layer, u16 x, u16 y, u8 color) {
-    if(x < screen_width && y < screen_height) {
-        Uint32 i = x + y *screen_width;
-        if(color != layer[i]) {
-            layer[i] = color;
-        }
+    if (x >= screen_width || y >= screen_height) {
+        return;
+    }
+    Uint32 i = x + y *screen_width;
+    if(color != layer[i]) {
+        layer[i] = color;
     }
     dirty_lines[y] |= 1;
 }