a-retide.adb

------------------------------------------------------------------------------
--                                                                          --
--                  GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                --
--                                                                          --
--                   A D A . R E A L _ T I M E . D E L A Y S                --
--                                                                          --
--                                  B o d y                                 --
--                                                                          --
--  Copyright (C) 1992-2010, 2016-2018, 2020 Free Software Foundation, Inc. --
--                                                                          --
-- GNARL is free software; you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
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-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
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-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNARL was developed by the GNARL team at Florida State University.       --
-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
--                                                                          --
------------------------------------------------------------------------------

--  Modified from GCC 4.9.1 for FreeRTOS-Ada.

with Interfaces;
with System.Tasking;

package body Ada.Real_Time.Delays is

   procedure Delay_Until (T : Time) is
      procedure vTaskDelay (Ticks_To_Delay : Interfaces.Unsigned_32)
      with
        Import,
        Convention => C,
        External_Name => "vTaskDelay";
      Now : constant Time := Clock;
      Ticks_To_Delay : constant Time := (if T > Now then T - Now else 0);
      Self_Id : constant System.Tasking.Task_Id := System.Tasking.Self;
   begin
      --  This is a restricted profile, so we must raise Program_Error
      --  if this potentially blocking operation is called from a
      --  protected action.
      if Self_Id.Common.Protected_Action_Nesting > 0 then
         raise Program_Error with "potentially blocking operation";
      end if;

      vTaskDelay (Interfaces.Unsigned_32 (Ticks_To_Delay));
   end Delay_Until;

   -----------------
   -- To_Duration --
   -----------------

   function To_Duration (T : Time) return Duration is
      pragma Unreferenced (T);
   begin
      return raise Program_Error
        with "shouldn't be trying to convert Time to Duration";
   end To_Duration;

end Ada.Real_Time.Delays;