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------------------------------------------------------------------------------

--                                                                          --

--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --

--                                                                          --

--                  S Y S T E M . O S _ P R I M I T I V E S                 --

--                                                                          --

--                                  B o d y                                 --

--                                                                          --

--          Copyright (C) 1998-2009, 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.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- 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    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- 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.     --

--                                                                          --

------------------------------------------------------------------------------

--  This version is for VxWorks targets

with System.OS_Interface;

--  Since the thread library is part of the VxWorks kernel, using OS_Interface

--  is not a problem here, as long as we only use System.OS_Interface as a

--  set of C imported routines: using Ada routines from this package would

--  create a dependency on libgnarl in libgnat, which is not desirable.

with Interfaces.C;

package body System.OS_Primitives is

   use System.OS_Interface;

   use type Interfaces.C.int;

   ------------------------

   -- Internal functions --

   ------------------------

   function To_Clock_Ticks (D : Duration) return int;

   --  Convert a duration value (in seconds) into clock ticks.

   --  Note that this routine is duplicated from System.OS_Interface since

   --  as explained above, we do not want to depend on libgnarl

   function To_Clock_Ticks (D : Duration) return int is

      Ticks          : Long_Long_Integer;

      Rate_Duration  : Duration;

      Ticks_Duration : Duration;

   begin

      if D < 0.0 then

         return -1;

      end if;

      --  Ensure that the duration can be converted to ticks

      --  at the current clock tick rate without overflowing.

      Rate_Duration := Duration (sysClkRateGet);

      if D > (Duration'Last / Rate_Duration) then

         Ticks := Long_Long_Integer (int'Last);

      else

         Ticks_Duration := D * Rate_Duration;

         Ticks := Long_Long_Integer (Ticks_Duration);

         if Ticks_Duration > Duration (Ticks) then

            Ticks := Ticks + 1;

         end if;

         if Ticks > Long_Long_Integer (int'Last) then

            Ticks := Long_Long_Integer (int'Last);

         end if;

      end if;

      return int (Ticks);

   end To_Clock_Ticks;

   -----------

   -- Clock --

   -----------

   function Clock return Duration is

      TS     : aliased timespec;

      Result : int;

   begin

      Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access);

      pragma Assert (Result = 0);

      return Duration (TS.ts_sec) + Duration (TS.ts_nsec) / 10#1#E9;

   end Clock;

   ---------------------

   -- Monotonic_Clock --

   ---------------------

   function Monotonic_Clock return Duration renames Clock;

   -----------------

   -- Timed_Delay --

   -----------------

   procedure Timed_Delay

     (Time : Duration;

      Mode : Integer)

   is

      Rel_Time   : Duration;

      Abs_Time   : Duration;

      Base_Time  : constant Duration := Clock;

      Check_Time : Duration := Base_Time;

      Ticks      : int;

      Result     : int;

      pragma Unreferenced (Result);

   begin

      if Mode = Relative then

         Rel_Time := Time;

         Abs_Time := Time + Check_Time;

      else

         Rel_Time := Time - Check_Time;

         Abs_Time := Time;

      end if;

      if Rel_Time > 0.0 then

         loop

            Ticks := To_Clock_Ticks (Rel_Time);

            if Mode = Relative and then Ticks < int'Last then

               --  The first tick will delay anytime between 0 and

               --  1 / sysClkRateGet seconds, so we need to add one to

               --  be on the safe side.

               Ticks := Ticks + 1;

            end if;

            Result := taskDelay (Ticks);

            Check_Time := Clock;

            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;

            Rel_Time := Abs_Time - Check_Time;

         end loop;

      end if;

   end Timed_Delay;

   ----------------

   -- Initialize --

   ----------------

   procedure Initialize is

   begin

      null;

   end Initialize;

end System.OS_Primitives;