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