243 lines
9.2 KiB
Ada
243 lines
9.2 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 . I N T E R R U P T _ M A N A G E M E N T --
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-- --
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-- B o d y --
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-- --
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-- $Revision: 1.1 $
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-- --
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-- Copyright (C) 1991-2001, Florida State University --
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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 default version of this package
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-- This is a Sun OS (FSU THREADS) version of this package
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-- PLEASE DO NOT add any dependences on other packages. ??? why not ???
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-- This package is designed to work with or without tasking support.
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-- See the other warnings in the package specification before making
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-- any modifications to this file.
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-- Make a careful study of all signals available under the OS, to see which
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-- need to be reserved, kept always unmasked, or kept always unmasked. Be on
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-- the lookout for special signals that may be used by the thread library.
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-- Since this is a multi target file, the signal <-> exception mapping
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-- is simple minded. If you need a more precise and target specific
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-- signal handling, create a new s-intman.adb that will fit your needs.
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-- This file assumes that:
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--
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-- SIGFPE, SIGILL, SIGSEGV and SIGBUS exist. They are mapped as follows:
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-- SIGPFE => Constraint_Error
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-- SIGILL => Program_Error
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-- SIGSEGV => Storage_Error
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-- SIGBUS => Storage_Error
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--
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-- SIGINT exists and will be kept unmasked unless the pragma
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-- Unreserve_All_Interrupts is specified anywhere in the application.
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--
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-- System.OS_Interface contains the following:
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-- SIGADAABORT: the signal that will be used to abort tasks.
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-- Unmasked: the OS specific set of signals that should be unmasked in
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-- all the threads. SIGADAABORT is unmasked by
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-- default
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-- Reserved: the OS specific set of signals that are reserved.
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with Interfaces.C;
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-- used for int and other types
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with System.OS_Interface;
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-- used for various Constants, Signal and types
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package body System.Interrupt_Management is
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use Interfaces.C;
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use System.OS_Interface;
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type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID;
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Exception_Interrupts : constant Interrupt_List :=
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(SIGFPE, SIGILL, SIGSEGV, SIGBUS);
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Unreserve_All_Interrupts : Interfaces.C.int;
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pragma Import
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(C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
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-----------------------
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-- Local Subprograms --
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-----------------------
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procedure Notify_Exception (signo : Signal);
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-- This function identifies the Ada exception to be raised using
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-- the information when the system received a synchronous signal.
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-- Since this function is machine and OS dependent, different code
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-- has to be provided for different target.
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----------------------
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-- Notify_Exception --
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----------------------
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Signal_Mask : aliased sigset_t;
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-- The set of signals handled by Notify_Exception
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procedure Notify_Exception (signo : Signal) is
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Result : Interfaces.C.int;
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begin
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-- With the __builtin_longjmp, the signal mask is not restored, so we
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-- need to restore it explicitly.
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Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null);
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pragma Assert (Result = 0);
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-- Check that treatment of exception propagation here
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-- is consistent with treatment of the abort signal in
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-- System.Task_Primitives.Operations.
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case signo is
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when SIGFPE =>
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raise Constraint_Error;
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when SIGILL =>
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raise Program_Error;
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when SIGSEGV =>
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raise Storage_Error;
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when SIGBUS =>
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raise Storage_Error;
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when others =>
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null;
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end case;
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end Notify_Exception;
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---------------------------
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-- Initialize_Interrupts --
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---------------------------
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-- Nothing needs to be done on this platform.
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procedure Initialize_Interrupts is
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begin
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null;
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end Initialize_Interrupts;
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-------------------------
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-- Package Elaboration --
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-------------------------
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begin
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declare
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act : aliased struct_sigaction;
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old_act : aliased struct_sigaction;
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Result : Interfaces.C.int;
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begin
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-- Need to call pthread_init very early because it is doing signal
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-- initializations.
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pthread_init;
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Abort_Task_Interrupt := SIGADAABORT;
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act.sa_handler := Notify_Exception'Address;
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act.sa_flags := 0;
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-- On some targets, we set sa_flags to SA_NODEFER so that during the
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-- handler execution we do not change the Signal_Mask to be masked for
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-- the Signal.
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-- This is a temporary fix to the problem that the Signal_Mask is
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-- not restored after the exception (longjmp) from the handler.
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-- The right fix should be made in sigsetjmp so that we save
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-- the Signal_Set and restore it after a longjmp.
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-- Since SA_NODEFER is obsolete, instead we reset explicitly
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-- the mask in the exception handler.
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Result := sigemptyset (Signal_Mask'Access);
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pragma Assert (Result = 0);
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-- ??? For the same reason explained above, we can't mask these
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-- signals because otherwise we won't be able to catch more than
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-- one signal.
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act.sa_mask := Signal_Mask;
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Keep_Unmasked (Abort_Task_Interrupt) := True;
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Keep_Unmasked (SIGXCPU) := True;
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Keep_Unmasked (SIGFPE) := True;
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Result :=
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sigaction
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(Signal (SIGFPE), act'Unchecked_Access,
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old_act'Unchecked_Access);
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pragma Assert (Result = 0);
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-- By keeping SIGINT unmasked, allow the user to do a Ctrl-C, but at
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-- the same time, disable the ability of handling this signal via
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-- package Ada.Interrupts.
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-- The pragma Unreserve_All_Interrupts let the user the ability to
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-- change this behavior.
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if Unreserve_All_Interrupts = 0 then
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Keep_Unmasked (SIGINT) := True;
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end if;
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for J in
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Exception_Interrupts'First + 1 .. Exception_Interrupts'Last
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loop
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Keep_Unmasked (Exception_Interrupts (J)) := True;
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if Unreserve_All_Interrupts = 0 then
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Result :=
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sigaction
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(Signal (Exception_Interrupts (J)), act'Unchecked_Access,
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old_act'Unchecked_Access);
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pragma Assert (Result = 0);
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end if;
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end loop;
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for J in Unmasked'Range loop
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Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True;
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end loop;
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Reserve := Keep_Unmasked or Keep_Masked;
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for J in Reserved'Range loop
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Reserve (Interrupt_ID (Reserved (J))) := True;
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end loop;
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-- We do not have Signal 0 in reality. We just use this value
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-- to identify non-existent signals (see s-intnam.ads). Therefore,
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-- Signal 0 should not be used in all signal related operations hence
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-- mark it as reserved.
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Reserve (0) := True;
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end;
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end System.Interrupt_Management;
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