------------------------------------------------------------------------------ -- -- -- 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 -- -- -- -- 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, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, 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 contexted switch 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;