1259 lines
35 KiB
Ada
1259 lines
35 KiB
Ada
------------------------------------------------------------------------------
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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 _ P R I M I T I V E S . O P E R A T I O N S --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2006, 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 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, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, 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. --
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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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-- This is a NT (native) version of this package
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-- This package contains all the GNULL primitives that interface directly
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-- with the underlying OS.
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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.Tasking.Debug;
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-- used for Known_Tasks
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with System.OS_Primitives;
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-- used for Delay_Modes
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with Interfaces.C;
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-- used for int
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-- size_t
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with Interfaces.C.Strings;
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-- used for Null_Ptr
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with System.Task_Info;
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-- used for Unspecified_Task_Info
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with System.Interrupt_Management;
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-- used for Initialize
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with System.Soft_Links;
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-- used for Abort_Defer/Undefer
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-- We use System.Soft_Links instead of System.Tasking.Initialization
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-- because the later is a higher level package that we shouldn't depend on.
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-- For example when using the restricted run time, it is replaced by
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-- System.Tasking.Restricted.Stages.
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with Unchecked_Deallocation;
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package body System.Task_Primitives.Operations is
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package SSL renames System.Soft_Links;
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use System.Tasking.Debug;
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use System.Tasking;
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use Interfaces.C;
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use Interfaces.C.Strings;
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use System.OS_Interface;
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use System.Parameters;
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use System.OS_Primitives;
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pragma Link_With ("-Xlinker --stack=0x200000,0x1000");
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-- Change the default stack size (2 MB) for tasking programs on Windows.
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-- This allows about 1000 tasks running at the same time. Note that
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-- we set the stack size for non tasking programs on System unit.
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-- Also note that under Windows XP, we use a Windows XP extension to
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-- specify the stack size on a per task basis, as done under other OSes.
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----------------
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-- Local Data --
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----------------
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Environment_Task_Id : Task_Id;
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-- A variable to hold Task_Id for the environment task
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Single_RTS_Lock : aliased RTS_Lock;
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-- This is a lock to allow only one thread of control in the RTS at
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-- a time; it is used to execute in mutual exclusion from all other tasks.
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-- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
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Time_Slice_Val : Integer;
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pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
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Dispatching_Policy : Character;
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pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
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function Get_Policy (Prio : System.Any_Priority) return Character;
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pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
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-- Get priority specific dispatching policy
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Foreign_Task_Elaborated : aliased Boolean := True;
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-- Used to identified fake tasks (i.e., non-Ada Threads)
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------------------------------------
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-- The thread local storage index --
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------------------------------------
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TlsIndex : DWORD;
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pragma Export (Ada, TlsIndex);
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-- To ensure that this variable won't be local to this package, since
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-- in some cases, inlining forces this variable to be global anyway.
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--------------------
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-- Local Packages --
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--------------------
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package Specific is
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function Is_Valid_Task return Boolean;
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pragma Inline (Is_Valid_Task);
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-- Does executing thread have a TCB?
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procedure Set (Self_Id : Task_Id);
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pragma Inline (Set);
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-- Set the self id for the current task
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end Specific;
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package body Specific is
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function Is_Valid_Task return Boolean is
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begin
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return TlsGetValue (TlsIndex) /= System.Null_Address;
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end Is_Valid_Task;
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procedure Set (Self_Id : Task_Id) is
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Succeeded : BOOL;
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begin
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Succeeded := TlsSetValue (TlsIndex, To_Address (Self_Id));
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pragma Assert (Succeeded = True);
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end Set;
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end Specific;
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---------------------------------
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-- Support for foreign threads --
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---------------------------------
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function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
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-- Allocate and Initialize a new ATCB for the current Thread
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function Register_Foreign_Thread
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(Thread : Thread_Id) return Task_Id is separate;
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----------------------------------
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-- Condition Variable Functions --
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----------------------------------
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procedure Initialize_Cond (Cond : access Condition_Variable);
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-- Initialize given condition variable Cond
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procedure Finalize_Cond (Cond : access Condition_Variable);
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-- Finalize given condition variable Cond
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procedure Cond_Signal (Cond : access Condition_Variable);
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-- Signal condition variable Cond
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procedure Cond_Wait
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(Cond : access Condition_Variable;
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L : access RTS_Lock);
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-- Wait on conditional variable Cond, using lock L
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procedure Cond_Timed_Wait
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(Cond : access Condition_Variable;
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L : access RTS_Lock;
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Rel_Time : Duration;
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Timed_Out : out Boolean;
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Status : out Integer);
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-- Do timed wait on condition variable Cond using lock L. The duration
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-- of the timed wait is given by Rel_Time. When the condition is
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-- signalled, Timed_Out shows whether or not a time out occurred.
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-- Status is only valid if Timed_Out is False, in which case it
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-- shows whether Cond_Timed_Wait completed successfully.
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---------------------
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-- Initialize_Cond --
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---------------------
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procedure Initialize_Cond (Cond : access Condition_Variable) is
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hEvent : HANDLE;
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begin
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hEvent := CreateEvent (null, True, False, Null_Ptr);
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pragma Assert (hEvent /= 0);
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Cond.all := Condition_Variable (hEvent);
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end Initialize_Cond;
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-------------------
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-- Finalize_Cond --
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-------------------
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-- No such problem here, DosCloseEventSem has been derived.
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-- What does such refer to in above comment???
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procedure Finalize_Cond (Cond : access Condition_Variable) is
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Result : BOOL;
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begin
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Result := CloseHandle (HANDLE (Cond.all));
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pragma Assert (Result = True);
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end Finalize_Cond;
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-----------------
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-- Cond_Signal --
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-----------------
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procedure Cond_Signal (Cond : access Condition_Variable) is
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Result : BOOL;
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begin
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Result := SetEvent (HANDLE (Cond.all));
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pragma Assert (Result = True);
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end Cond_Signal;
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---------------
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-- Cond_Wait --
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---------------
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-- Pre-assertion: Cond is posted
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-- L is locked.
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-- Post-assertion: Cond is posted
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-- L is locked.
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procedure Cond_Wait
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(Cond : access Condition_Variable;
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L : access RTS_Lock)
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is
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Result : DWORD;
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Result_Bool : BOOL;
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begin
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-- Must reset Cond BEFORE L is unlocked
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Result_Bool := ResetEvent (HANDLE (Cond.all));
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pragma Assert (Result_Bool = True);
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Unlock (L);
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-- No problem if we are interrupted here: if the condition is signaled,
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-- WaitForSingleObject will simply not block
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Result := WaitForSingleObject (HANDLE (Cond.all), Wait_Infinite);
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pragma Assert (Result = 0);
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Write_Lock (L);
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end Cond_Wait;
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---------------------
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-- Cond_Timed_Wait --
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---------------------
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-- Pre-assertion: Cond is posted
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-- L is locked.
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-- Post-assertion: Cond is posted
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-- L is locked.
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procedure Cond_Timed_Wait
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(Cond : access Condition_Variable;
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L : access RTS_Lock;
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Rel_Time : Duration;
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Timed_Out : out Boolean;
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Status : out Integer)
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is
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Time_Out_Max : constant DWORD := 16#FFFF0000#;
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-- NT 4 cannot handle timeout values that are too large,
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-- e.g. DWORD'Last - 1
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Time_Out : DWORD;
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Result : BOOL;
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Wait_Result : DWORD;
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begin
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-- Must reset Cond BEFORE L is unlocked
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Result := ResetEvent (HANDLE (Cond.all));
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pragma Assert (Result = True);
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Unlock (L);
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-- No problem if we are interrupted here: if the condition is signaled,
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-- WaitForSingleObject will simply not block
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if Rel_Time <= 0.0 then
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Timed_Out := True;
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Wait_Result := 0;
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else
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if Rel_Time >= Duration (Time_Out_Max) / 1000 then
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Time_Out := Time_Out_Max;
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else
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Time_Out := DWORD (Rel_Time * 1000);
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end if;
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Wait_Result := WaitForSingleObject (HANDLE (Cond.all), Time_Out);
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if Wait_Result = WAIT_TIMEOUT then
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Timed_Out := True;
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Wait_Result := 0;
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else
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Timed_Out := False;
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end if;
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end if;
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Write_Lock (L);
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-- Ensure post-condition
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if Timed_Out then
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Result := SetEvent (HANDLE (Cond.all));
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pragma Assert (Result = True);
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end if;
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Status := Integer (Wait_Result);
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end Cond_Timed_Wait;
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------------------
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-- Stack_Guard --
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------------------
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-- The underlying thread system sets a guard page at the
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-- bottom of a thread stack, so nothing is needed.
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-- ??? Check the comment above
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procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
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pragma Warnings (Off, T);
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pragma Warnings (Off, On);
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begin
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null;
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end Stack_Guard;
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--------------------
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-- Get_Thread_Id --
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--------------------
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function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
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begin
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return T.Common.LL.Thread;
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end Get_Thread_Id;
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----------
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-- Self --
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----------
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function Self return Task_Id is
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Self_Id : constant Task_Id := To_Task_Id (TlsGetValue (TlsIndex));
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begin
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if Self_Id = null then
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return Register_Foreign_Thread (GetCurrentThread);
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else
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return Self_Id;
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end if;
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end Self;
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---------------------
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-- Initialize_Lock --
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---------------------
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-- Note: mutexes and cond_variables needed per-task basis are
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-- initialized in Intialize_TCB and the Storage_Error is handled.
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-- Other mutexes (such as RTS_Lock, Memory_Lock...) used in
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-- the RTS is initialized before any status change of RTS.
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-- Therefore raising Storage_Error in the following routines
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-- should be able to be handled safely.
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procedure Initialize_Lock
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(Prio : System.Any_Priority;
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L : access Lock)
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is
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begin
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InitializeCriticalSection (L.Mutex'Access);
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L.Owner_Priority := 0;
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L.Priority := Prio;
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end Initialize_Lock;
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procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
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pragma Unreferenced (Level);
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begin
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InitializeCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access);
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end Initialize_Lock;
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-------------------
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-- Finalize_Lock --
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-------------------
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procedure Finalize_Lock (L : access Lock) is
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begin
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DeleteCriticalSection (L.Mutex'Access);
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end Finalize_Lock;
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procedure Finalize_Lock (L : access RTS_Lock) is
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begin
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DeleteCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access);
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end Finalize_Lock;
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----------------
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-- Write_Lock --
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----------------
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procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
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begin
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L.Owner_Priority := Get_Priority (Self);
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if L.Priority < L.Owner_Priority then
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Ceiling_Violation := True;
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return;
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end if;
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EnterCriticalSection (L.Mutex'Access);
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Ceiling_Violation := False;
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end Write_Lock;
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procedure Write_Lock
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(L : access RTS_Lock;
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Global_Lock : Boolean := False)
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is
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begin
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if not Single_Lock or else Global_Lock then
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EnterCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access);
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end if;
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end Write_Lock;
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procedure Write_Lock (T : Task_Id) is
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begin
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if not Single_Lock then
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EnterCriticalSection
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(CRITICAL_SECTION (T.Common.LL.L)'Unrestricted_Access);
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end if;
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end Write_Lock;
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---------------
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-- Read_Lock --
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---------------
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procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
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begin
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Write_Lock (L, Ceiling_Violation);
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end Read_Lock;
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------------
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-- Unlock --
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------------
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procedure Unlock (L : access Lock) is
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begin
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LeaveCriticalSection (L.Mutex'Access);
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end Unlock;
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procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
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begin
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if not Single_Lock or else Global_Lock then
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LeaveCriticalSection (CRITICAL_SECTION (L.all)'Unrestricted_Access);
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end if;
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end Unlock;
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procedure Unlock (T : Task_Id) is
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begin
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if not Single_Lock then
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LeaveCriticalSection
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(CRITICAL_SECTION (T.Common.LL.L)'Unrestricted_Access);
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end if;
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end Unlock;
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|
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-----------
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-- Sleep --
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-----------
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procedure Sleep
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(Self_ID : Task_Id;
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Reason : System.Tasking.Task_States)
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is
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pragma Unreferenced (Reason);
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begin
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pragma Assert (Self_ID = Self);
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if Single_Lock then
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Cond_Wait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
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else
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Cond_Wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
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end if;
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if Self_ID.Deferral_Level = 0
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and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
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then
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Unlock (Self_ID);
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raise Standard'Abort_Signal;
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end if;
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end Sleep;
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|
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-----------------
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-- Timed_Sleep --
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-----------------
|
|
|
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-- This is for use within the run-time system, so abort is
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-- assumed to be already deferred, and the caller should be
|
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-- holding its own ATCB lock.
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|
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procedure Timed_Sleep
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(Self_ID : Task_Id;
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Time : Duration;
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Mode : ST.Delay_Modes;
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Reason : System.Tasking.Task_States;
|
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Timedout : out Boolean;
|
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Yielded : out Boolean)
|
|
is
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pragma Unreferenced (Reason);
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Check_Time : Duration := Monotonic_Clock;
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Rel_Time : Duration;
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Abs_Time : Duration;
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Result : Integer;
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Local_Timedout : Boolean;
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begin
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Timedout := True;
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Yielded := False;
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|
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if Mode = Relative then
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Rel_Time := Time;
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Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
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else
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Rel_Time := Time - Check_Time;
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Abs_Time := Time;
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end if;
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|
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if Rel_Time > 0.0 then
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loop
|
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exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
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or else Self_ID.Pending_Priority_Change;
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|
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if Single_Lock then
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Cond_Timed_Wait (Self_ID.Common.LL.CV'Access,
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Single_RTS_Lock'Access, Rel_Time, Local_Timedout, Result);
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else
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Cond_Timed_Wait (Self_ID.Common.LL.CV'Access,
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Self_ID.Common.LL.L'Access, Rel_Time, Local_Timedout, Result);
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end if;
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|
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Check_Time := Monotonic_Clock;
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exit when Abs_Time <= Check_Time;
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|
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if not Local_Timedout then
|
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|
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-- Somebody may have called Wakeup for us
|
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|
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Timedout := False;
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exit;
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end if;
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|
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Rel_Time := Abs_Time - Check_Time;
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end loop;
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end if;
|
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end Timed_Sleep;
|
|
|
|
-----------------
|
|
-- Timed_Delay --
|
|
-----------------
|
|
|
|
procedure Timed_Delay
|
|
(Self_ID : Task_Id;
|
|
Time : Duration;
|
|
Mode : ST.Delay_Modes)
|
|
is
|
|
Check_Time : Duration := Monotonic_Clock;
|
|
Rel_Time : Duration;
|
|
Abs_Time : Duration;
|
|
Timedout : Boolean;
|
|
|
|
Result : Integer;
|
|
pragma Warnings (Off, Integer);
|
|
|
|
begin
|
|
if Single_Lock then
|
|
Lock_RTS;
|
|
end if;
|
|
|
|
Write_Lock (Self_ID);
|
|
|
|
if Mode = Relative then
|
|
Rel_Time := Time;
|
|
Abs_Time := Time + Check_Time;
|
|
else
|
|
Rel_Time := Time - Check_Time;
|
|
Abs_Time := Time;
|
|
end if;
|
|
|
|
if Rel_Time > 0.0 then
|
|
Self_ID.Common.State := Delay_Sleep;
|
|
|
|
loop
|
|
if Self_ID.Pending_Priority_Change then
|
|
Self_ID.Pending_Priority_Change := False;
|
|
Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
|
|
Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
|
|
end if;
|
|
|
|
exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
|
|
|
|
if Single_Lock then
|
|
Cond_Timed_Wait (Self_ID.Common.LL.CV'Access,
|
|
Single_RTS_Lock'Access,
|
|
Rel_Time, Timedout, Result);
|
|
else
|
|
Cond_Timed_Wait (Self_ID.Common.LL.CV'Access,
|
|
Self_ID.Common.LL.L'Access,
|
|
Rel_Time, Timedout, Result);
|
|
end if;
|
|
|
|
Check_Time := Monotonic_Clock;
|
|
exit when Abs_Time <= Check_Time;
|
|
|
|
Rel_Time := Abs_Time - Check_Time;
|
|
end loop;
|
|
|
|
Self_ID.Common.State := Runnable;
|
|
end if;
|
|
|
|
Unlock (Self_ID);
|
|
|
|
if Single_Lock then
|
|
Unlock_RTS;
|
|
end if;
|
|
|
|
Yield;
|
|
end Timed_Delay;
|
|
|
|
------------
|
|
-- Wakeup --
|
|
------------
|
|
|
|
procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
|
|
pragma Unreferenced (Reason);
|
|
begin
|
|
Cond_Signal (T.Common.LL.CV'Access);
|
|
end Wakeup;
|
|
|
|
-----------
|
|
-- Yield --
|
|
-----------
|
|
|
|
procedure Yield (Do_Yield : Boolean := True) is
|
|
begin
|
|
if Do_Yield then
|
|
Sleep (0);
|
|
end if;
|
|
end Yield;
|
|
|
|
------------------
|
|
-- Set_Priority --
|
|
------------------
|
|
|
|
type Prio_Array_Type is array (System.Any_Priority) of Integer;
|
|
pragma Atomic_Components (Prio_Array_Type);
|
|
|
|
Prio_Array : Prio_Array_Type;
|
|
-- Global array containing the id of the currently running task for
|
|
-- each priority.
|
|
--
|
|
-- Note: we assume that we are on a single processor with run-til-blocked
|
|
-- scheduling.
|
|
|
|
procedure Set_Priority
|
|
(T : Task_Id;
|
|
Prio : System.Any_Priority;
|
|
Loss_Of_Inheritance : Boolean := False)
|
|
is
|
|
Res : BOOL;
|
|
Array_Item : Integer;
|
|
|
|
begin
|
|
Res := SetThreadPriority
|
|
(T.Common.LL.Thread, Interfaces.C.int (Underlying_Priorities (Prio)));
|
|
pragma Assert (Res = True);
|
|
|
|
if Dispatching_Policy = 'F' or else Get_Policy (Prio) = 'F' then
|
|
|
|
-- Annex D requirement [RM D.2.2 par. 9]:
|
|
-- If the task drops its priority due to the loss of inherited
|
|
-- priority, it is added at the head of the ready queue for its
|
|
-- new active priority.
|
|
|
|
if Loss_Of_Inheritance
|
|
and then Prio < T.Common.Current_Priority
|
|
then
|
|
Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
|
|
Prio_Array (T.Common.Base_Priority) := Array_Item;
|
|
|
|
loop
|
|
-- Let some processes a chance to arrive
|
|
|
|
Yield;
|
|
|
|
-- Then wait for our turn to proceed
|
|
|
|
exit when Array_Item = Prio_Array (T.Common.Base_Priority)
|
|
or else Prio_Array (T.Common.Base_Priority) = 1;
|
|
end loop;
|
|
|
|
Prio_Array (T.Common.Base_Priority) :=
|
|
Prio_Array (T.Common.Base_Priority) - 1;
|
|
end if;
|
|
end if;
|
|
|
|
T.Common.Current_Priority := Prio;
|
|
end Set_Priority;
|
|
|
|
------------------
|
|
-- Get_Priority --
|
|
------------------
|
|
|
|
function Get_Priority (T : Task_Id) return System.Any_Priority is
|
|
begin
|
|
return T.Common.Current_Priority;
|
|
end Get_Priority;
|
|
|
|
----------------
|
|
-- Enter_Task --
|
|
----------------
|
|
|
|
-- There were two paths were we needed to call Enter_Task :
|
|
-- 1) from System.Task_Primitives.Operations.Initialize
|
|
-- 2) from System.Tasking.Stages.Task_Wrapper
|
|
|
|
-- The thread initialisation has to be done only for the first case.
|
|
|
|
-- This is because the GetCurrentThread NT call does not return the real
|
|
-- thread handler but only a "pseudo" one. It is not possible to release
|
|
-- the thread handle and free the system ressources from this "pseudo"
|
|
-- handle. So we really want to keep the real thread handle set in
|
|
-- System.Task_Primitives.Operations.Create_Task during thread creation.
|
|
|
|
procedure Enter_Task (Self_ID : Task_Id) is
|
|
procedure Init_Float;
|
|
pragma Import (C, Init_Float, "__gnat_init_float");
|
|
-- Properly initializes the FPU for x86 systems
|
|
|
|
begin
|
|
Specific.Set (Self_ID);
|
|
Init_Float;
|
|
|
|
Self_ID.Common.LL.Thread_Id := GetCurrentThreadId;
|
|
|
|
Lock_RTS;
|
|
|
|
for J in Known_Tasks'Range loop
|
|
if Known_Tasks (J) = null then
|
|
Known_Tasks (J) := Self_ID;
|
|
Self_ID.Known_Tasks_Index := J;
|
|
exit;
|
|
end if;
|
|
end loop;
|
|
|
|
Unlock_RTS;
|
|
end Enter_Task;
|
|
|
|
--------------
|
|
-- New_ATCB --
|
|
--------------
|
|
|
|
function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
|
|
begin
|
|
return new Ada_Task_Control_Block (Entry_Num);
|
|
end New_ATCB;
|
|
|
|
-------------------
|
|
-- Is_Valid_Task --
|
|
-------------------
|
|
|
|
function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
|
|
|
|
-----------------------------
|
|
-- Register_Foreign_Thread --
|
|
-----------------------------
|
|
|
|
function Register_Foreign_Thread return Task_Id is
|
|
begin
|
|
if Is_Valid_Task then
|
|
return Self;
|
|
else
|
|
return Register_Foreign_Thread (GetCurrentThread);
|
|
end if;
|
|
end Register_Foreign_Thread;
|
|
|
|
--------------------
|
|
-- Initialize_TCB --
|
|
--------------------
|
|
|
|
procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
|
|
begin
|
|
-- Initialize thread ID to 0, this is needed to detect threads that
|
|
-- are not yet activated.
|
|
|
|
Self_ID.Common.LL.Thread := 0;
|
|
|
|
Initialize_Cond (Self_ID.Common.LL.CV'Access);
|
|
|
|
if not Single_Lock then
|
|
Initialize_Lock (Self_ID.Common.LL.L'Access, ATCB_Level);
|
|
end if;
|
|
|
|
Succeeded := True;
|
|
end Initialize_TCB;
|
|
|
|
-----------------
|
|
-- Create_Task --
|
|
-----------------
|
|
|
|
procedure Create_Task
|
|
(T : Task_Id;
|
|
Wrapper : System.Address;
|
|
Stack_Size : System.Parameters.Size_Type;
|
|
Priority : System.Any_Priority;
|
|
Succeeded : out Boolean)
|
|
is
|
|
Initial_Stack_Size : constant := 1024;
|
|
-- We set the initial stack size to 1024. On Windows version prior to XP
|
|
-- there is no way to fix a task stack size. Only the initial stack size
|
|
-- can be set, the operating system will raise the task stack size if
|
|
-- needed.
|
|
|
|
function Is_Windows_XP return Integer;
|
|
pragma Import (C, Is_Windows_XP, "__gnat_is_windows_xp");
|
|
-- Returns 1 if running on Windows XP
|
|
|
|
hTask : HANDLE;
|
|
TaskId : aliased DWORD;
|
|
pTaskParameter : System.OS_Interface.PVOID;
|
|
Result : DWORD;
|
|
Entry_Point : PTHREAD_START_ROUTINE;
|
|
|
|
begin
|
|
pTaskParameter := To_Address (T);
|
|
|
|
Entry_Point := To_PTHREAD_START_ROUTINE (Wrapper);
|
|
|
|
if Is_Windows_XP = 1 then
|
|
hTask := CreateThread
|
|
(null,
|
|
DWORD (Stack_Size),
|
|
Entry_Point,
|
|
pTaskParameter,
|
|
DWORD (Create_Suspended) or
|
|
DWORD (Stack_Size_Param_Is_A_Reservation),
|
|
TaskId'Unchecked_Access);
|
|
else
|
|
hTask := CreateThread
|
|
(null,
|
|
Initial_Stack_Size,
|
|
Entry_Point,
|
|
pTaskParameter,
|
|
DWORD (Create_Suspended),
|
|
TaskId'Unchecked_Access);
|
|
end if;
|
|
|
|
-- Step 1: Create the thread in blocked mode
|
|
|
|
if hTask = 0 then
|
|
raise Storage_Error;
|
|
end if;
|
|
|
|
-- Step 2: set its TCB
|
|
|
|
T.Common.LL.Thread := hTask;
|
|
|
|
-- Step 3: set its priority (child has inherited priority from parent)
|
|
|
|
Set_Priority (T, Priority);
|
|
|
|
if Time_Slice_Val = 0
|
|
or else Dispatching_Policy = 'F'
|
|
or else Get_Policy (Priority) = 'F'
|
|
then
|
|
-- Here we need Annex D semantics so we disable the NT priority
|
|
-- boost. A priority boost is temporarily given by the system to a
|
|
-- thread when it is taken out of a wait state.
|
|
|
|
SetThreadPriorityBoost (hTask, DisablePriorityBoost => True);
|
|
end if;
|
|
|
|
-- Step 4: Now, start it for good:
|
|
|
|
Result := ResumeThread (hTask);
|
|
pragma Assert (Result = 1);
|
|
|
|
Succeeded := Result = 1;
|
|
end Create_Task;
|
|
|
|
------------------
|
|
-- Finalize_TCB --
|
|
------------------
|
|
|
|
procedure Finalize_TCB (T : Task_Id) is
|
|
Self_ID : Task_Id := T;
|
|
Result : DWORD;
|
|
Succeeded : BOOL;
|
|
Is_Self : constant Boolean := T = Self;
|
|
|
|
procedure Free is new
|
|
Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
|
|
|
|
begin
|
|
if not Single_Lock then
|
|
Finalize_Lock (T.Common.LL.L'Access);
|
|
end if;
|
|
|
|
Finalize_Cond (T.Common.LL.CV'Access);
|
|
|
|
if T.Known_Tasks_Index /= -1 then
|
|
Known_Tasks (T.Known_Tasks_Index) := null;
|
|
end if;
|
|
|
|
if Self_ID.Common.LL.Thread /= 0 then
|
|
|
|
-- This task has been activated. Wait for the thread to terminate
|
|
-- then close it. this is needed to release system ressources.
|
|
|
|
Result := WaitForSingleObject (T.Common.LL.Thread, Wait_Infinite);
|
|
pragma Assert (Result /= WAIT_FAILED);
|
|
Succeeded := CloseHandle (T.Common.LL.Thread);
|
|
pragma Assert (Succeeded = True);
|
|
end if;
|
|
|
|
Free (Self_ID);
|
|
|
|
if Is_Self then
|
|
Specific.Set (null);
|
|
end if;
|
|
end Finalize_TCB;
|
|
|
|
---------------
|
|
-- Exit_Task --
|
|
---------------
|
|
|
|
procedure Exit_Task is
|
|
begin
|
|
Specific.Set (null);
|
|
end Exit_Task;
|
|
|
|
----------------
|
|
-- Abort_Task --
|
|
----------------
|
|
|
|
procedure Abort_Task (T : Task_Id) is
|
|
pragma Unreferenced (T);
|
|
begin
|
|
null;
|
|
end Abort_Task;
|
|
|
|
----------------------
|
|
-- Environment_Task --
|
|
----------------------
|
|
|
|
function Environment_Task return Task_Id is
|
|
begin
|
|
return Environment_Task_Id;
|
|
end Environment_Task;
|
|
|
|
--------------
|
|
-- Lock_RTS --
|
|
--------------
|
|
|
|
procedure Lock_RTS is
|
|
begin
|
|
Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
|
|
end Lock_RTS;
|
|
|
|
----------------
|
|
-- Unlock_RTS --
|
|
----------------
|
|
|
|
procedure Unlock_RTS is
|
|
begin
|
|
Unlock (Single_RTS_Lock'Access, Global_Lock => True);
|
|
end Unlock_RTS;
|
|
|
|
----------------
|
|
-- Initialize --
|
|
----------------
|
|
|
|
procedure Initialize (Environment_Task : Task_Id) is
|
|
Discard : BOOL;
|
|
pragma Unreferenced (Discard);
|
|
|
|
begin
|
|
Environment_Task_Id := Environment_Task;
|
|
OS_Primitives.Initialize;
|
|
Interrupt_Management.Initialize;
|
|
|
|
if Time_Slice_Val = 0 or else Dispatching_Policy = 'F' then
|
|
|
|
-- Here we need Annex D semantics, switch the current process to the
|
|
-- High_Priority_Class.
|
|
|
|
Discard :=
|
|
OS_Interface.SetPriorityClass
|
|
(GetCurrentProcess, High_Priority_Class);
|
|
|
|
-- ??? In theory it should be possible to use the priority class
|
|
-- Realtime_Priority_Class but we suspect a bug in the NT scheduler
|
|
-- which prevents (in some obscure cases) a thread to get on top of
|
|
-- the running queue by another thread of lower priority. For
|
|
-- example cxd8002 ACATS test freeze.
|
|
end if;
|
|
|
|
TlsIndex := TlsAlloc;
|
|
|
|
-- Initialize the lock used to synchronize chain of all ATCBs
|
|
|
|
Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
|
|
|
|
Environment_Task.Common.LL.Thread := GetCurrentThread;
|
|
Enter_Task (Environment_Task);
|
|
end Initialize;
|
|
|
|
---------------------
|
|
-- Monotonic_Clock --
|
|
---------------------
|
|
|
|
function Monotonic_Clock return Duration
|
|
renames System.OS_Primitives.Monotonic_Clock;
|
|
|
|
-------------------
|
|
-- RT_Resolution --
|
|
-------------------
|
|
|
|
function RT_Resolution return Duration is
|
|
begin
|
|
return 0.000_001; -- 1 micro-second
|
|
end RT_Resolution;
|
|
|
|
----------------
|
|
-- Initialize --
|
|
----------------
|
|
|
|
procedure Initialize (S : in out Suspension_Object) is
|
|
begin
|
|
-- Initialize internal state. It is always initialized to False (ARM
|
|
-- D.10 par. 6).
|
|
|
|
S.State := False;
|
|
S.Waiting := False;
|
|
|
|
-- Initialize internal mutex
|
|
|
|
InitializeCriticalSection (S.L'Access);
|
|
|
|
-- Initialize internal condition variable
|
|
|
|
S.CV := CreateEvent (null, True, False, Null_Ptr);
|
|
pragma Assert (S.CV /= 0);
|
|
end Initialize;
|
|
|
|
--------------
|
|
-- Finalize --
|
|
--------------
|
|
|
|
procedure Finalize (S : in out Suspension_Object) is
|
|
Result : BOOL;
|
|
begin
|
|
-- Destroy internal mutex
|
|
|
|
DeleteCriticalSection (S.L'Access);
|
|
|
|
-- Destroy internal condition variable
|
|
|
|
Result := CloseHandle (S.CV);
|
|
pragma Assert (Result = True);
|
|
end Finalize;
|
|
|
|
-------------------
|
|
-- Current_State --
|
|
-------------------
|
|
|
|
function Current_State (S : Suspension_Object) return Boolean is
|
|
begin
|
|
-- We do not want to use lock on this read operation. State is marked
|
|
-- as Atomic so that we ensure that the value retrieved is correct.
|
|
|
|
return S.State;
|
|
end Current_State;
|
|
|
|
---------------
|
|
-- Set_False --
|
|
---------------
|
|
|
|
procedure Set_False (S : in out Suspension_Object) is
|
|
begin
|
|
SSL.Abort_Defer.all;
|
|
|
|
EnterCriticalSection (S.L'Access);
|
|
|
|
S.State := False;
|
|
|
|
LeaveCriticalSection (S.L'Access);
|
|
|
|
SSL.Abort_Undefer.all;
|
|
end Set_False;
|
|
|
|
--------------
|
|
-- Set_True --
|
|
--------------
|
|
|
|
procedure Set_True (S : in out Suspension_Object) is
|
|
Result : BOOL;
|
|
begin
|
|
SSL.Abort_Defer.all;
|
|
|
|
EnterCriticalSection (S.L'Access);
|
|
|
|
-- If there is already a task waiting on this suspension object then
|
|
-- we resume it, leaving the state of the suspension object to False,
|
|
-- as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
|
|
-- the state to True.
|
|
|
|
if S.Waiting then
|
|
S.Waiting := False;
|
|
S.State := False;
|
|
|
|
Result := SetEvent (S.CV);
|
|
pragma Assert (Result = True);
|
|
else
|
|
S.State := True;
|
|
end if;
|
|
|
|
LeaveCriticalSection (S.L'Access);
|
|
|
|
SSL.Abort_Undefer.all;
|
|
end Set_True;
|
|
|
|
------------------------
|
|
-- Suspend_Until_True --
|
|
------------------------
|
|
|
|
procedure Suspend_Until_True (S : in out Suspension_Object) is
|
|
Result : DWORD;
|
|
Result_Bool : BOOL;
|
|
begin
|
|
SSL.Abort_Defer.all;
|
|
|
|
EnterCriticalSection (S.L'Access);
|
|
|
|
if S.Waiting then
|
|
-- Program_Error must be raised upon calling Suspend_Until_True
|
|
-- if another task is already waiting on that suspension object
|
|
-- (ARM D.10 par. 10).
|
|
|
|
LeaveCriticalSection (S.L'Access);
|
|
|
|
SSL.Abort_Undefer.all;
|
|
|
|
raise Program_Error;
|
|
else
|
|
-- Suspend the task if the state is False. Otherwise, the task
|
|
-- continues its execution, and the state of the suspension object
|
|
-- is set to False (ARM D.10 par. 9).
|
|
|
|
if S.State then
|
|
S.State := False;
|
|
|
|
LeaveCriticalSection (S.L'Access);
|
|
|
|
SSL.Abort_Undefer.all;
|
|
else
|
|
S.Waiting := True;
|
|
|
|
-- Must reset CV BEFORE L is unlocked
|
|
|
|
Result_Bool := ResetEvent (S.CV);
|
|
pragma Assert (Result_Bool = True);
|
|
|
|
LeaveCriticalSection (S.L'Access);
|
|
|
|
SSL.Abort_Undefer.all;
|
|
|
|
Result := WaitForSingleObject (S.CV, Wait_Infinite);
|
|
pragma Assert (Result = 0);
|
|
end if;
|
|
end if;
|
|
end Suspend_Until_True;
|
|
|
|
----------------
|
|
-- Check_Exit --
|
|
----------------
|
|
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-- Dummy versions. The only currently working versions is for solaris
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-- (native).
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|
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function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
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pragma Unreferenced (Self_ID);
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begin
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|
return True;
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|
end Check_Exit;
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|
|
|
--------------------
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|
-- Check_No_Locks --
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|
--------------------
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|
|
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function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
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|
pragma Unreferenced (Self_ID);
|
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begin
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|
return True;
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end Check_No_Locks;
|
|
|
|
------------------
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|
-- Suspend_Task --
|
|
------------------
|
|
|
|
function Suspend_Task
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|
(T : ST.Task_Id;
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|
Thread_Self : Thread_Id) return Boolean
|
|
is
|
|
begin
|
|
if T.Common.LL.Thread /= Thread_Self then
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|
return SuspendThread (T.Common.LL.Thread) = NO_ERROR;
|
|
else
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|
return True;
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|
end if;
|
|
end Suspend_Task;
|
|
|
|
-----------------
|
|
-- Resume_Task --
|
|
-----------------
|
|
|
|
function Resume_Task
|
|
(T : ST.Task_Id;
|
|
Thread_Self : Thread_Id) return Boolean
|
|
is
|
|
begin
|
|
if T.Common.LL.Thread /= Thread_Self then
|
|
return ResumeThread (T.Common.LL.Thread) = NO_ERROR;
|
|
else
|
|
return True;
|
|
end if;
|
|
end Resume_Task;
|
|
|
|
end System.Task_Primitives.Operations;
|