178 lines
7.1 KiB
Ada
178 lines
7.1 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- S Y S T E M . T A S K I N G --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1991-2001 Florida State University --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNARL; see file COPYING. If not, write --
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-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
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-- MA 02111-1307, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. It is --
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-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
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-- State University (http://www.gnat.com). --
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-- --
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------------------------------------------------------------------------------
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pragma Polling (Off);
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-- Turn off polling, we do not want ATC polling to take place during
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-- tasking operations. It causes infinite loops and other problems.
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with System.Task_Primitives.Operations;
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-- used for Self
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with Unchecked_Deallocation;
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-- To recover from failure of ATCB initialization.
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with System.Storage_Elements;
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-- Needed for initializing Stack_Info.Size
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with System.Parameters;
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-- Used for Adjust_Storage_Size
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package body System.Tasking is
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package STPO renames System.Task_Primitives.Operations;
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procedure Free is new
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Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
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----------
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-- Self --
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----------
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function Self return Task_ID renames STPO.Self;
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---------------------
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-- Initialize_ATCB --
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---------------------
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procedure Initialize_ATCB
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(Self_ID : Task_ID;
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Task_Entry_Point : Task_Procedure_Access;
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Task_Arg : System.Address;
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Parent : Task_ID;
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Elaborated : Access_Boolean;
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Base_Priority : System.Any_Priority;
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Task_Info : System.Task_Info.Task_Info_Type;
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Stack_Size : System.Parameters.Size_Type;
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T : in out Task_ID;
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Success : out Boolean) is
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begin
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T.Common.State := Unactivated;
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-- Initialize T.Common.LL
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STPO.Initialize_TCB (T, Success);
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if not Success then
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Free (T);
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return;
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end if;
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T.Common.Parent := Parent;
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T.Common.Base_Priority := Base_Priority;
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T.Common.Current_Priority := 0;
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T.Common.Call := null;
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T.Common.Task_Arg := Task_Arg;
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T.Common.Task_Entry_Point := Task_Entry_Point;
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T.Common.Activator := Self_ID;
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T.Common.Wait_Count := 0;
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T.Common.Elaborated := Elaborated;
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T.Common.Activation_Failed := False;
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T.Common.Task_Info := Task_Info;
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if T.Common.Parent = null then
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-- For the environment task, the adjusted stack size is
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-- meaningless. For example, an unspecified Stack_Size means
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-- that the stack size is determined by the environment, or
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-- can grow dynamically. The Stack_Checking algorithm
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-- therefore needs to use the requested size, or 0 in
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-- case of an unknown size.
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T.Common.Compiler_Data.Pri_Stack_Info.Size :=
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Storage_Elements.Storage_Offset (Stack_Size);
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else
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T.Common.Compiler_Data.Pri_Stack_Info.Size :=
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Storage_Elements.Storage_Offset
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(Parameters.Adjust_Storage_Size (Stack_Size));
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end if;
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-- Link the task into the list of all tasks.
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T.Common.All_Tasks_Link := All_Tasks_List;
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All_Tasks_List := T;
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end Initialize_ATCB;
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Main_Task_Image : aliased String := "main_task";
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-- Declare a global variable to avoid allocating dynamic memory.
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Main_Priority : Priority;
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pragma Import (C, Main_Priority, "__gl_main_priority");
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----------------------------
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-- Tasking Initialization --
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----------------------------
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-- This block constitutes the first part of the initialization of the
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-- GNARL. This includes creating data structures to make the initial thread
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-- into the environment task. The last part of the initialization is done
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-- in System.Tasking.Initialization or System.Tasking.Restricted.Stages.
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-- All the initializations used to be in Tasking.Initialization, but this
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-- is no longer possible with the run time simplification (including
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-- optimized PO and the restricted run time) since one cannot rely on
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-- System.Tasking.Initialization being present, as was done before.
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begin
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declare
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T : Task_ID;
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Success : Boolean;
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Base_Priority : Any_Priority;
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begin
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-- Initialize Environment Task
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if Main_Priority = Unspecified_Priority then
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Base_Priority := Default_Priority;
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else
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Base_Priority := Main_Priority;
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end if;
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Success := True;
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T := STPO.New_ATCB (0);
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Initialize_ATCB
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(null, null, Null_Address, Null_Task, null, Base_Priority,
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Task_Info.Unspecified_Task_Info, 0, T, Success);
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pragma Assert (Success);
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STPO.Initialize (T);
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STPO.Set_Priority (T, T.Common.Base_Priority);
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T.Common.State := Runnable;
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T.Common.Task_Image := Main_Task_Image'Unrestricted_Access;
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-- Only initialize the first element since others are not relevant
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-- in ravenscar mode. Rest of the initialization is done in Init_RTS.
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T.Entry_Calls (1).Self := T;
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end;
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end System.Tasking;
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