Add interrupt handlers in cpu

src/interrupt.ml

@@ -6,15 +6,16 @@
  * LICENSE file at the top level directory of this source tree.
  *)
 
-(* let IME = ref false;; *)
+let ime = ref false;;
 
 type t =
-  |  V_Blank
-  |  LCD_Stat
-  |  Timer
-  |  Serial
-  |  Joypad
+  | V_Blank
+  | LCD_Stat
+  | Timer
+  | Serial
+  | Joypad
 
+(** Return the list of interrupt flags sorted by priority. *)
 let get_flags byte =
 
   let nth_interrupt i =
@@ -34,6 +35,6 @@ let get_flags byte =
         get_flag byte (i + 1) (interrupt :: accu)
       else
         get_flag byte (i + 1) accu
-    | _ -> accu in
+    | _ -> List.rev accu in
 
   get_flag byte 0 []