1------------------------------------------------------------------------------ 2-- -- 3-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- 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 . -- 6-- S P E C I F I C -- 7-- -- 8-- B o d y -- 9-- -- 10-- $Revision: 1.2 $ 11-- -- 12-- Copyright (C) 1991-2003, Florida State University -- 13-- Copyright (C) 2008-2012, Free Software Foundation, Inc. -- 14-- -- 15-- GNARL is free software; you can redistribute it and/or modify it under -- 16-- terms of the GNU General Public License as published by the Free Soft- -- 17-- ware Foundation; either version 3, or (at your option) any later ver- -- 18-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 19-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 20-- or FITNESS FOR A PARTICULAR PURPOSE. -- 21-- -- 22-- As a special exception under Section 7 of GPL version 3, you are granted -- 23-- additional permissions described in the GCC Runtime Library Exception, -- 24-- version 3.1, as published by the Free Software Foundation. -- 25-- -- 26-- You should have received a copy of the GNU General Public License and -- 27-- a copy of the GCC Runtime Library Exception along with this program; -- 28-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 29-- <http://www.gnu.org/licenses/>. -- 30-- -- 31-- GNARL was developed by the GNARL team at Florida State University. It is -- 32-- now maintained by Ada Core Technologies Inc. in cooperation with Florida -- 33-- State University (http://www.gnat.com). -- 34-- -- 35------------------------------------------------------------------------------ 36 37-- This is a RTEMS version of this package which uses a special 38-- variable for Ada self which is context switched implicitly by RTEMS. 39-- 40-- This is the same as the POSIX version except that an RTEMS variable 41-- is used instead of a POSIX key. 42 43separate (System.Task_Primitives.Operations) 44package body Specific is 45 46 -- The following gives the Ada run-time direct access to a variable 47 -- context switched by RTEMS at the lowest level. 48 49 ATCB_Key : System.Address; 50 pragma Import (C, ATCB_Key, "rtems_ada_self"); 51 52 ---------------- 53 -- Initialize -- 54 ---------------- 55 56 procedure Initialize (Environment_Task : Task_Id) is 57 pragma Warnings (Off, Environment_Task); 58 59 begin 60 ATCB_Key := To_Address (Environment_Task); 61 end Initialize; 62 63 ------------------- 64 -- Is_Valid_Task -- 65 ------------------- 66 67 function Is_Valid_Task return Boolean is 68 begin 69 return ATCB_Key /= System.Null_Address; 70 end Is_Valid_Task; 71 72 --------- 73 -- Set -- 74 --------- 75 76 procedure Set (Self_Id : Task_Id) is 77 begin 78 ATCB_Key := To_Address (Self_Id); 79 end Set; 80 81 ---------- 82 -- Self -- 83 ---------- 84 85 -- To make Ada tasks and C threads interoperate better, we have added some 86 -- functionality to Self. Suppose a C main program (with threads) calls an 87 -- Ada procedure and the Ada procedure calls the tasking runtime system. 88 -- Eventually, a call will be made to self. Since the call is not coming 89 -- from an Ada task, there will be no corresponding ATCB. 90 91 -- What we do in Self is to catch references that do not come from 92 -- recognized Ada tasks, and create an ATCB for the calling thread. 93 94 -- The new ATCB will be "detached" from the normal Ada task master 95 -- hierarchy, much like the existing implicitly created signal-server 96 -- tasks. 97 98 function Self return Task_Id is 99 Result : System.Address; 100 101 begin 102 Result := ATCB_Key; 103 104 -- If the key value is Null, then it is a non-Ada task. 105 106 if Result /= System.Null_Address then 107 return To_Task_Id (Result); 108 else 109 return Register_Foreign_Thread; 110 end if; 111 end Self; 112 113end Specific; 114