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------------------------------------------------------------------------------
-- --
-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K I N G --
-- --
-- B o d y --
-- --
-- $Revision: 1.38 $
-- --
-- Copyright (C) 1991-2001 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). --
-- --
------------------------------------------------------------------------------
pragma Polling (Off);
-- Turn off polling, we do not want ATC polling to take place during
-- tasking operations. It causes infinite loops and other problems.
with System.Task_Primitives.Operations;
-- used for Self
with Unchecked_Deallocation;
-- To recover from failure of ATCB initialization.
with System.Storage_Elements;
-- Needed for initializing Stack_Info.Size
with System.Parameters;
-- Used for Adjust_Storage_Size
package body System.Tasking is
package STPO renames System.Task_Primitives.Operations;
procedure Free is new
Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
----------
-- Self --
----------
function Self return Task_ID renames STPO.Self;
---------------------
-- Initialize_ATCB --
---------------------
-- Call this only with abort deferred and holding All_Tasks_L.
procedure Initialize_ATCB
(Self_ID : Task_ID;
Task_Entry_Point : Task_Procedure_Access;
Task_Arg : System.Address;
Parent : Task_ID;
Elaborated : Access_Boolean;
Base_Priority : System.Any_Priority;
Task_Info : System.Task_Info.Task_Info_Type;
Stack_Size : System.Parameters.Size_Type;
T : in out Task_ID;
Success : out Boolean) is
begin
T.Common.State := Unactivated;
-- Initialize T.Common.LL
STPO.Initialize_TCB (T, Success);
if not Success then
Free (T);
return;
end if;
T.Common.Parent := Parent;
T.Common.Base_Priority := Base_Priority;
T.Common.Current_Priority := 0;
T.Common.Call := null;
T.Common.Task_Arg := Task_Arg;
T.Common.Task_Entry_Point := Task_Entry_Point;
T.Common.Activator := Self_ID;
T.Common.Wait_Count := 0;
T.Common.Elaborated := Elaborated;
T.Common.Activation_Failed := False;
T.Common.Task_Info := Task_Info;
if T.Common.Parent = null then
-- For the environment task, the adjusted stack size is
-- meaningless. For example, an unspecified Stack_Size means
-- that the stack size is determined by the environment, or
-- can grow dynamically. The Stack_Checking algorithm
-- therefore needs to use the requested size, or 0 in
-- case of an unknown size.
T.Common.Compiler_Data.Pri_Stack_Info.Size :=
Storage_Elements.Storage_Offset (Stack_Size);
else
T.Common.Compiler_Data.Pri_Stack_Info.Size :=
Storage_Elements.Storage_Offset
(Parameters.Adjust_Storage_Size (Stack_Size));
end if;
-- Link the task into the list of all tasks.
T.Common.All_Tasks_Link := All_Tasks_List;
All_Tasks_List := T;
end Initialize_ATCB;
Main_Task_Image : aliased String := "main_task";
-- Declare a global variable to avoid allocating dynamic memory.
Main_Priority : Priority;
pragma Import (C, Main_Priority, "__gl_main_priority");
----------------------------
-- Tasking Initialization --
----------------------------
-- This block constitutes the first part of the initialization of the
-- GNARL. This includes creating data structures to make the initial thread
-- into the environment task. The last part of the initialization is done
-- in System.Tasking.Initialization or System.Tasking.Restricted.Stages.
-- All the initializations used to be in Tasking.Initialization, but this
-- is no longer possible with the run time simplification (including
-- optimized PO and the restricted run time) since one cannot rely on
-- System.Tasking.Initialization being present, as was done before.
begin
declare
T : Task_ID;
Success : Boolean;
Base_Priority : Any_Priority;
begin
-- Initialize Environment Task
if Main_Priority = Unspecified_Priority then
Base_Priority := Default_Priority;
else
Base_Priority := Main_Priority;
end if;
Success := True;
T := STPO.New_ATCB (0);
Initialize_ATCB
(null, null, Null_Address, Null_Task, null, Base_Priority,
Task_Info.Unspecified_Task_Info, 0, T, Success);
pragma Assert (Success);
STPO.Initialize (T);
STPO.Set_Priority (T, T.Common.Base_Priority);
T.Common.State := Runnable;
T.Common.Task_Image := Main_Task_Image'Unrestricted_Access;
-- Only initialize the first element since others are not relevant
-- in ravenscar mode. Rest of the initialization is done in Init_RTS.
T.Entry_Calls (1).Self := T;
end;
end System.Tasking;
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