diff --git a/abstract-machine/am/src/platform/nemu/ioe/gpu.c b/abstract-machine/am/src/platform/nemu/ioe/gpu.c
index 7063e85..9cc28d6 100644
--- a/abstract-machine/am/src/platform/nemu/ioe/gpu.c
+++ b/abstract-machine/am/src/platform/nemu/ioe/gpu.c
@@ -31,10 +31,12 @@ void __am_gpu_config(AM_GPU_CONFIG_T *cfg) {
 
 void __am_gpu_fbdraw(AM_GPU_FBDRAW_T *ctl) {
   GET_W(w);
-  unsigned char* fb_addr = (unsigned char*)FB_ADDR;
+  uint32_t* fb_addr = (uint32_t*)FB_ADDR;
   for (int i = 0; i < ctl->h; i++) {
     for (int j = 0; j < ctl->w; j++) {
-      outl((uintptr_t)(fb_addr + 4 * ((ctl->y + i) * w + (ctl->x + j))), ((uint32_t*)ctl->pixels)[w * i + j]);
+      outl((uintptr_t)(fb_addr + 
+        ((ctl->y + i) * w + (ctl->x + j))),
+        ((uint32_t*)ctl->pixels)[w * i + j]);
     }
   }
   if (ctl->sync) {