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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) 2008-2012, 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. 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.
ATCB_Key : System.Address;
pragma Import (C, ATCB_Key, "rtems_ada_self");
----------------
-- Initialize --
----------------
procedure Initialize (Environment_Task : Task_Id) is
pragma Warnings (Off, Environment_Task);
begin
ATCB_Key := To_Address (Environment_Task);
end Initialize;
-------------------
-- Is_Valid_Task --
-------------------
function Is_Valid_Task return Boolean is
begin
return ATCB_Key /= System.Null_Address;
end Is_Valid_Task;
---------
-- Set --
---------
procedure Set (Self_Id : Task_Id) is
begin
ATCB_Key := 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 := ATCB_Key;
-- 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;
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