diff --git a/include/picconf.h b/include/picconf.h
index da97cad5..a609439d 100644
--- a/include/picconf.h
+++ b/include/picconf.h
@@ -3,6 +3,7 @@
 
 #define PIC_ARENA_SIZE 100
 #define PIC_HEAP_SIZE 8192
+#define PIC_STACK_SIZE 1024
 
 #define DEBUG 1
 
diff --git a/src/state.c b/src/state.c
index d6111bfa..3e7b1565 100644
--- a/src/state.c
+++ b/src/state.c
@@ -26,8 +26,8 @@ pic_open()
   pic = (pic_state *)malloc(sizeof(pic_state));
 
   /* prepare VM stack */
-  pic->stbase = pic->sp = (pic_value *)malloc(sizeof(pic_value) * 1024);
-  pic->stend = pic->stbase + 1024;
+  pic->stbase = pic->sp = (pic_value *)malloc(sizeof(pic_value) * PIC_STACK_SIZE);
+  pic->stend = pic->stbase + PIC_STACK_SIZE;
 
   /* memory heap */
   pic->heap = (struct heap_page *)malloc(sizeof(struct heap_page));