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-- GHDL Run Time (GRT) - Callbacks.
-- Copyright (C) 2015 Tristan Gingold
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 2 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program. If not, see <gnu.org/licenses>.
--
-- As a special exception, if other files instantiate generics from this
-- unit, or you link this unit with other files to produce an executable,
-- this unit does not by itself cause the resulting executable to be
-- covered by the GNU General Public License. This exception does not
-- however invalidate any other reasons why the executable file might be
-- covered by the GNU Public License.
with System;
with Grt.Vhdl_Types; use Grt.Vhdl_Types;
-- Callbacks are user registered procedures that are called during simulation.
-- They are used to implement vpi/vhpi callbacks, but also some features like
-- vcd or fst.
package Grt.Callbacks is
pragma Preelaborate (Grt.Callbacks);
-- It would be nice to use OOP (tagged types and overriding), but this is
-- not anymore available in the context of pragma No_Run_Time.
-- Furthermore, that wouldn't be that convenient because of lack of
-- multiple inheritance.
--
-- Thus the use of a 'generic' callback type. The type Address is used for
-- any pointer type.
type Callback_Acc is access procedure (Arg : System.Address);
type Callback_Handle is private;
type Callback_List is limited private;
pragma Preelaborable_Initialization (Callback_List);
type Callback_Time_List is limited private;
pragma Preelaborable_Initialization (Callback_Time_List);
-- Register a timeout: PROC will be called with parameter ARG at time T
-- at the beginning of the cycle (before any process). Insertion is O(n).
procedure Register_Callback_At
(List : in out Callback_Time_List;
Handle : out Callback_Handle;
T : Std_Time;
Proc : Callback_Acc;
Arg : System.Address := System.Null_Address);
type Callback_Mode is (Timed, Repeat, Oneshot);
subtype Callback_Non_Timed_Mode is Callback_Mode range Repeat .. Oneshot;
procedure Register_Callback
(List : in out Callback_List;
Handle : out Callback_Handle;
Mode : Callback_Mode;
Proc : Callback_Acc;
Arg : System.Address := System.Null_Address);
-- Delete callback.
-- In fact the callback is just marked as deleted, but will be removed
-- only at the point it would be called.
procedure Delete_Callback (Handle : Callback_Handle);
-- Call the callbacks.
procedure Call_Callbacks (List : in out Callback_List);
procedure Call_Time_Callbacks (List : in out Callback_Time_List);
-- Return the date of the earliest callbacks (or Std_Time'Last if none).
function Get_First_Time (List : Callback_Time_List) return Std_Time;
pragma Inline (Get_First_Time);
-- Return True if there is at least one callback in the list.
function Has_Callbacks (List : Callback_List) return Boolean;
pragma Inline (Has_Callbacks);
private
type Cb_Cell;
type Callback_Handle is access Cb_Cell;
type Cb_Cell is record
T : Std_Time;
Mode : Callback_Mode;
Proc : Callback_Acc;
Arg : System.Address;
Next : Callback_Handle;
end record;
type Callback_List is limited record
First, Last : Callback_Handle := null;
end record;
type Callback_Time_List is limited record
First : Callback_Handle := null;
First_Timeout : Std_Time := Std_Time'Last;
end record;
end Grt.Callbacks;
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