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

--                                                                          --

--                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --

--                                                                          --

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

--                              S P E C I F I C                             --

--                                                                          --

--                                  B o d y                                 --

--                                                                          --

--                             $Revision: 1.2 $

--                                                                          --

--            Copyright (C) 1991-2003, Florida State University             --

--            Copyright (C) 2008, 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 2,  or (at your option) any later ver- --

-- sion. GNARL 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.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNARL; see file COPYING.  If not, write --

-- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --

-- Boston, MA 02110-1301, USA.                                              --

--                                                                          --

-- 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.                                      --

--                                                                          --

-- GNARL was developed by the GNARL team at Florida State University. It is --

-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --

-- State University (http://www.gnat.com).                                  --

--                                                                          --

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

--  This is a RTEMS version of this package which uses a special

--  variable for Ada self which is context switched implicitly by RTEMS.

--

--  This is the same as the POSIX version except that an RTEMS variable

--  is used instead of a POSIX key.

separate (System.Task_Primitives.Operations)

package body Specific is

   --  The following gives the Ada run-time direct access to a variable

   --  context switched by RTEMS at the lowest level.

   RTEMS_Ada_Self : System.Address;

   pragma Import (C, RTEMS_Ada_Self, "rtems_ada_self");

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

   -- Initialize --

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

   procedure Initialize (Environment_Task : Task_Id) is

      pragma Warnings (Off, Environment_Task);

   begin

      ATCB_Key := No_Key;

      RTEMS_Ada_Self := To_Address (Environment_Task);

   end Initialize;

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

   -- Is_Valid_Task --

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

   function Is_Valid_Task return Boolean is

   begin

      return RTEMS_Ada_Self /= System.Null_Address;

   end Is_Valid_Task;

   ---------

   -- Set --

   ---------

   procedure Set (Self_Id : Task_Id) is

   begin

      RTEMS_Ada_Self := To_Address (Self_Id);

   end Set;

   ----------

   -- Self --

   ----------

   --  To make Ada tasks and C threads interoperate better, we have added some

   --  functionality to Self. Suppose a C main program (with threads) calls an

   --  Ada procedure and the Ada procedure calls the tasking runtime system.

   --  Eventually, a call will be made to self. Since the call is not coming

   --  from an Ada task, there will be no corresponding ATCB.

   --  What we do in Self is to catch references that do not come from

   --  recognized Ada tasks, and create an ATCB for the calling thread.

   --  The new ATCB will be "detached" from the normal Ada task master

   --  hierarchy, much like the existing implicitly created signal-server

   --  tasks.

   function Self return Task_Id is

      Result : System.Address;

   begin

      Result := RTEMS_Ada_Self;

      --  If the key value is Null, then it is a non-Ada task.

      if Result /= System.Null_Address then

         return To_Task_Id (Result);

      else

         return Register_Foreign_Thread;

      end if;

   end Self;

end Specific;