------------------------------------------------------------------------------ -- -- -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- S Y S T E M . T A S K I N G -- -- -- -- B o d y -- -- -- -- -- -- 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 -- --------------------- 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;