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129 lines
6.2 KiB
Ada
129 lines
6.2 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- S Y S T E M . T A S K _ 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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-- $Revision: 1.1 $ --
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-- --
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-- Copyright (C) 1991-1997, 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, 59 Temple Place - Suite 330, Boston, --
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-- MA 02111-1307, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. It is --
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-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
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-- State University (http://www.gnat.com). --
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-- --
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------------------------------------------------------------------------------
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-- This is the FreeBSD PTHREADS version of this package. Contributed
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-- by Daniel M. Eischen (eischen@vigrid.com).
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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 Interfaces.C;
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-- used for int
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-- size_t
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with System.OS_Interface;
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-- used for pthread_mutex_t
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-- pthread_cond_t
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-- pthread_t
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package System.Task_Primitives is
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type Lock is limited private;
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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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-- Should be used inside the runtime system.
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-- The difference between Lock and the RTS_Lock is that the later
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-- one serves only as a semaphore so that do not check for
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-- ceiling violations.
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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
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-- basis. A component of this type is guaranteed to be included
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-- in the Ada_Task_Control_Block.
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private
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type Lock is new System.OS_Interface.pthread_mutex_t;
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type RTS_Lock is new System.OS_Interface.pthread_mutex_t;
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type Private_Data is record
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Thread : aliased System.OS_Interface.pthread_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).
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-- They put the same value (thr_self value). We do not want to
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-- use lock on those operations and the only thing we have to
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-- make sure is that they are updated in atomic fashion.
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LWP : aliased System.Address;
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-- This field is not relevant on all targets. Currently only SGI and
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-- AiX updates it. The purpose of this field is to provide a better
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-- tasking support on gdb. The order of the two first fields (Thread
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-- and LWP) is important.
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CV : aliased System.OS_Interface.pthread_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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Current_Priority : Interfaces.C.int := 0;
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-- Active priority, except that the effects of protected object
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-- priority ceilings are not reflected. This only reflects explicit
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-- priority changes and priority inherited through task activation
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-- and rendezvous.
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--
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-- Ada 95 notes: In Ada 95, this field will be transferred to the
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-- Priority field of an Entry_Calls component when an entry call
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-- is initiated. The Priority of the Entry_Calls component will not
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-- change for the duration of the call. The accepting task can
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-- use it to boost its own priority without fear of its changing in
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-- the meantime.
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--
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-- This can safely be used in the priority ordering
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-- of entry queues. Once a call is queued, its priority does not
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-- change.
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--
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-- Since an entry call cannot be made while executing
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-- a protected action, the priority of a task will never reflect a
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-- priority ceiling change at the point of an entry call.
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--
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-- Protection: Only written by Self, and only accessed when Acceptor
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-- accepts an entry or when Created activates, at which points Self is
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-- suspended.
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Stack_Size : Interfaces.C.size_t;
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-- Requested stack size.
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-- Protection: Only used by Self.
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end record;
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end System.Task_Primitives;
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