289 lines
11 KiB
Ada
289 lines
11 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT 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) 1992-2014, Free Software Foundation, Inc. --
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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 3, or (at your option) any later ver- --
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-- sion. GNAT 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. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. --
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-- Extensive contributions were provided by Ada Core Technologies, Inc. --
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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 tasking
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-- operations. It causes infinite loops and other problems.
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with System.Task_Primitives.Operations;
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with System.Storage_Elements;
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package body System.Tasking is
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package STPO renames System.Task_Primitives.Operations;
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---------------------
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-- Detect_Blocking --
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---------------------
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function Detect_Blocking return Boolean is
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GL_Detect_Blocking : Integer;
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pragma Import (C, GL_Detect_Blocking, "__gl_detect_blocking");
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-- Global variable exported by the binder generated file. A value equal
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-- to 1 indicates that pragma Detect_Blocking is active, while 0 is used
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-- for the pragma not being present.
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begin
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return GL_Detect_Blocking = 1;
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end Detect_Blocking;
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-----------------------
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-- Number_Of_Entries --
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-----------------------
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function Number_Of_Entries (Self_Id : Task_Id) return Entry_Index is
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begin
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return Entry_Index (Self_Id.Entry_Num);
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end Number_Of_Entries;
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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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-- Storage_Size --
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------------------
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function Storage_Size (T : Task_Id) return System.Parameters.Size_Type is
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begin
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return
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System.Parameters.Size_Type
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(T.Common.Compiler_Data.Pri_Stack_Info.Size);
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end Storage_Size;
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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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Base_CPU : System.Multiprocessors.CPU_Range;
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Domain : Dispatching_Domain_Access;
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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 : Task_Id;
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Success : out Boolean)
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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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return;
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end if;
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-- Note that use of an aggregate here for this assignment
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-- would be illegal, because Common_ATCB is limited because
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-- Task_Primitives.Private_Data is limited.
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T.Common.Parent := Parent;
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T.Common.Base_Priority := Base_Priority;
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T.Common.Base_CPU := Base_CPU;
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-- The Domain defaults to that of the activator. But that can be null in
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-- the case of foreign threads (see Register_Foreign_Thread), in which
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-- case we default to the System_Domain.
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if Domain /= null then
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T.Common.Domain := Domain;
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elsif Self_ID.Common.Domain /= null then
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T.Common.Domain := Self_ID.Common.Domain;
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else
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T.Common.Domain := System_Domain;
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end if;
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pragma Assert (T.Common.Domain /= null);
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T.Common.Current_Priority := 0;
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T.Common.Protected_Action_Nesting := 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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T.Common.Global_Task_Lock_Nesting := 0;
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T.Common.Fall_Back_Handler := null;
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T.Common.Specific_Handler := null;
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T.Common.Debug_Events := (others => False);
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T.Common.Task_Image_Len := 0;
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if T.Common.Parent = null then
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-- For the environment task, the adjusted stack size is meaningless.
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-- For example, an unspecified Stack_Size means that the stack size
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-- is determined by the environment, or can grow dynamically. The
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-- Stack_Checking algorithm therefore needs to use the requested
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-- size, or 0 in 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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----------------
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-- Initialize --
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----------------
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Main_Task_Image : constant String := "main_task";
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-- Image of environment task
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Main_Priority : Integer;
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pragma Import (C, Main_Priority, "__gl_main_priority");
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-- Priority for main task. Note that this is of type Integer, not Priority,
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-- because we use the value -1 to indicate the default main priority, and
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-- that is of course not in Priority'range.
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Main_CPU : Integer;
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pragma Import (C, Main_CPU, "__gl_main_cpu");
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-- Affinity for main task. Note that this is of type Integer, not
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-- CPU_Range, because we use the value -1 to indicate the unassigned
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-- affinity, and that is of course not in CPU_Range'Range.
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Initialized : Boolean := False;
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-- Used to prevent multiple calls to Initialize
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procedure Initialize is
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T : Task_Id;
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Base_Priority : Any_Priority;
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Base_CPU : System.Multiprocessors.CPU_Range;
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Success : Boolean;
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use type System.Multiprocessors.CPU_Range;
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begin
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if Initialized then
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return;
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end if;
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Initialized := True;
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-- Initialize Environment Task
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Base_Priority :=
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(if Main_Priority = Unspecified_Priority
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then Default_Priority
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else Priority (Main_Priority));
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Base_CPU :=
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(if Main_CPU = Unspecified_CPU
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then System.Multiprocessors.Not_A_Specific_CPU
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else System.Multiprocessors.CPU_Range (Main_CPU));
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-- At program start-up the environment task is allocated to the default
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-- system dispatching domain.
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-- Make sure that the processors which are not available are not taken
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-- into account. Use Number_Of_CPUs to know the exact number of
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-- processors in the system at execution time.
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System_Domain :=
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new Dispatching_Domain'
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(Multiprocessors.CPU'First .. Multiprocessors.Number_Of_CPUs =>
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True);
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T := STPO.New_ATCB (0);
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Initialize_ATCB
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(Self_ID => null,
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Task_Entry_Point => null,
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Task_Arg => Null_Address,
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Parent => Null_Task,
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Elaborated => null,
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Base_Priority => Base_Priority,
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Base_CPU => Base_CPU,
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Domain => System_Domain,
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Task_Info => Task_Info.Unspecified_Task_Info,
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Stack_Size => 0,
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T => T,
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Success => 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_Len := Main_Task_Image'Length;
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T.Common.Task_Image (Main_Task_Image'Range) := Main_Task_Image;
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Dispatching_Domain_Tasks :=
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new Array_Allocated_Tasks'
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(Multiprocessors.CPU'First .. Multiprocessors.Number_Of_CPUs => 0);
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-- Signal that this task is being allocated to a processor
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if Base_CPU /= System.Multiprocessors.Not_A_Specific_CPU then
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-- Increase the number of tasks attached to the CPU to which this
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-- task is allocated.
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Dispatching_Domain_Tasks (Base_CPU) :=
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Dispatching_Domain_Tasks (Base_CPU) + 1;
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end if;
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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 Initialize;
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---------------------
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-- Set_Entry_Names --
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---------------------
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procedure Set_Entry_Names
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(Self_Id : Task_Id;
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Names : Task_Entry_Names_Access)
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is
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begin
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Self_Id.Entry_Names := Names;
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end Set_Entry_Names;
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end System.Tasking;
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