diff --git a/am/src/native/ioe/gpu.c b/am/src/native/ioe/gpu.c
index 0309d50..fc386df 100644
--- a/am/src/native/ioe/gpu.c
+++ b/am/src/native/ioe/gpu.c
@@ -3,12 +3,12 @@
 #include <fenv.h>
 
 //#define MODE_800x600
+#define WINDOW_W 800
+#define WINDOW_H 600
 #ifdef MODE_800x600
-# define W    800
-# define H    600
+const int disp_w = WINDOW_W, disp_h = WINDOW_H;
 #else
-# define W    400
-# define H    300
+const int disp_w = 400, disp_h = 300;
 #endif
 
 #define FPS   60
@@ -31,13 +31,8 @@ void __am_gpu_init() {
   SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER);
   window = SDL_CreateWindow("Native Application",
       SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
-#ifdef MODE_800x600
-      W, H,
-#else
-      W * 2, H * 2,
-#endif
-      SDL_WINDOW_OPENGL);
-  surface = SDL_CreateRGBSurface(SDL_SWSURFACE, W, H, 32,
+      WINDOW_W, WINDOW_H, SDL_WINDOW_OPENGL);
+  surface = SDL_CreateRGBSurface(SDL_SWSURFACE, disp_w, disp_h, 32,
       RMASK, GMASK, BMASK, AMASK);
   SDL_AddTimer(1000 / FPS, texture_sync, NULL);
 }
@@ -45,7 +40,7 @@ void __am_gpu_init() {
 void __am_gpu_config(AM_GPU_CONFIG_T *cfg) {
   *cfg = (AM_GPU_CONFIG_T) {
     .present = true, .has_accel = false,
-    .width = W, .height = H,
+    .width = disp_w, .height = disp_h,
     .vmemsz = 0
   };
 }