diff --git a/src/event.c b/src/event.c
index e42f7f7..65cfc3a 100644
--- a/src/event.c
+++ b/src/event.c
@@ -16,7 +16,7 @@
 
 static struct {
   event_t buffer[BUFFER_SIZE];
-  int writei, readi;
+  unsigned writei, readi;
 } events;
 
 
diff --git a/src/keyboard.c b/src/keyboard.c
index bf8523e..2d0c1cf 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -159,7 +159,7 @@ typedef struct { unsigned char type, code, isrepeat; } KeyEvent;
 
 volatile struct {
   KeyEvent data[32];
-  int readi, writei;
+  unsigned readi, writei;
 } keyboard_events;
 
 _go32_dpmi_seginfo old_keyb_handler_seginfo, new_keyb_handler_seginfo;