149 lines
6.4 KiB
Ada
149 lines
6.4 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 --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2005, 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 Solaris version of this package
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-- This package provides low-level support for most tasking features
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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.OS_Interface;
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-- used for mutex_t
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-- cond_t
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-- thread_t
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with Unchecked_Conversion;
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package System.Task_Primitives is
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pragma Preelaborate;
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type Lock is limited private;
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type Lock_Ptr is access all Lock;
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-- Should be used for implementation of protected objects
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type RTS_Lock is limited private;
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type RTS_Lock_Ptr is access all RTS_Lock;
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-- Should be used inside the runtime system. The difference between Lock
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-- and the RTS_Lock is that the later one serves only as a semaphore so
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-- that do not check for ceiling violations.
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function To_Lock_Ptr is new Unchecked_Conversion (RTS_Lock_Ptr, Lock_Ptr);
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type Suspension_Object is limited private;
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-- Should be used for the implementation of Ada.Synchronous_Task_Control
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type Task_Body_Access is access procedure;
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-- Pointer to the task body's entry point (or possibly a wrapper
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-- declared local to the GNARL).
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type Private_Data is limited private;
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-- Any information that the GNULLI needs maintained on a per-task basis.
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-- A component of this type is guaranteed to be included in the
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-- Ada_Task_Control_Block.
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private
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type Private_Task_Serial_Number is mod 2 ** 64;
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-- Used to give each task a unique serial number
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type Base_Lock is new System.OS_Interface.mutex_t;
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type Owner_Int is new Integer;
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for Owner_Int'Alignment use Standard'Maximum_Alignment;
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type Owner_ID is access all Owner_Int;
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function To_Owner_ID is
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new Unchecked_Conversion (System.Address, Owner_ID);
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type Lock is record
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L : aliased Base_Lock;
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Ceiling : System.Any_Priority := System.Any_Priority'First;
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Saved_Priority : System.Any_Priority := System.Any_Priority'First;
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Owner : Owner_ID;
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Next : Lock_Ptr;
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Level : Private_Task_Serial_Number := 0;
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Buddy : Owner_ID;
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Frozen : Boolean := False;
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end record;
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type RTS_Lock is new Lock;
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type Suspension_Object is record
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State : Boolean;
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pragma Atomic (State);
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-- Boolean that indicates whether the object is open. This field is
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-- marked Atomic to ensure that we can read its value without locking
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-- the access to the Suspension_Object.
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Waiting : Boolean;
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-- Flag showing if there is a task already suspended on this object
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L : aliased System.OS_Interface.mutex_t;
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-- Protection for ensuring mutual exclusion on the Suspension_Object
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CV : aliased System.OS_Interface.cond_t;
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-- Condition variable used to queue threads until condition is signaled
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end record;
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-- Note that task support on gdb relies on the fact that the first two
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-- fields of Private_Data are Thread and LWP.
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type Private_Data is record
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Thread : aliased System.OS_Interface.thread_t;
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pragma Atomic (Thread);
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-- Thread field may be updated by two different threads of control.
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-- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
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-- value (thr_self value). We do not want to use lock on those
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-- operations and the only thing we have to make sure is that they are
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-- updated in atomic fashion.
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LWP : System.OS_Interface.lwpid_t;
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-- The LWP id of the thread. Set by self in Enter_Task
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CV : aliased System.OS_Interface.cond_t;
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L : aliased RTS_Lock;
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-- Protection for all components is lock L
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Active_Priority : System.Any_Priority := System.Any_Priority'First;
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-- Simulated active priority, used iff Priority_Ceiling_Support is True
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Locking : Lock_Ptr;
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Locks : Lock_Ptr;
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Wakeups : Natural := 0;
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end record;
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end System.Task_Primitives;
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