Reorganize src/ directory

src/core/interrupt.ml

@@ -0,0 +1,66 @@
+(**
+ * Copyright (c) 2016, Fabien Freling
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD 2-clause license found in the
+ * LICENSE file at the top level directory of this source tree.
+ *)
+
+(** Interrupt Master Enable flag *)
+let gIME = ref false
+
+let ie_addr = 0xFFFF
+let if_addr = 0xFFF0
+
+type t =
+  | V_Blank
+  | LCD_Stat
+  | Timer
+  | Serial
+  | Joypad
+
+
+let get_flag_mask = function
+  | V_Blank  -> 0b00000001
+  | LCD_Stat -> 0b00000010
+  | Timer    -> 0b00000100
+  | Serial   -> 0b00001000
+  | Joypad   -> 0b00010000
+
+(** Return the list of interrupt flags sorted by priority. *)
+let get_flags byte =
+
+  let nth_interrupt i =
+    match i with
+    | 0 -> V_Blank
+    | 1 -> LCD_Stat
+    | 2 -> Timer
+    | 3 -> Serial
+    | 4 -> Joypad
+    | _ -> failwith "Invalid interrupt index." in
+
+  let rec get_flag byte i accu =
+    match i with
+    | 0 | 1 | 2 | 3 | 4 ->
+      if Bit.is_set byte i then
+        let interrupt = nth_interrupt i in
+        get_flag byte (i + 1) (interrupt :: accu)
+      else
+        get_flag byte (i + 1) accu
+    | _ -> List.rev accu in
+
+  get_flag byte 0 []
+
+
+(** Interrupt Enable *)
+let get_IE mem = Memory.get mem ie_addr |> int_of_char
+
+(** Interrupt Flag *)
+let get_IF mem = Memory.get mem if_addr |> int_of_char
+
+let reset_IF_flag flag mem =
+  let if_reg = get_IF mem in
+  let flag_mask = get_flag_mask flag in
+  let new_if_reg = if_reg land (lnot flag_mask) |> char_of_int in
+  Memory.set mem if_addr new_if_reg
+