120 lines
6.4 KiB
Ada
120 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 . 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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-- S p e c --
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-- --
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-- Copyright (C) 1991-2009, Free Software Foundation, Inc. --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. --
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-- Extensive contributions were provided by Ada Core Technologies, Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This is the Alpha/VMS version of this package
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-- This package encapsulates and centralizes information about all uses of
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-- interrupts (or signals), including the target-dependent mapping of
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-- interrupts (or signals) to exceptions.
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-- PLEASE DO NOT add any with-clauses to this package
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-- PLEASE DO NOT put any subprogram declarations with arguments of type
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-- Interrupt_ID into the visible part of this package.
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-- The type Interrupt_ID is used to derive the type in Ada.Interrupts, and
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-- adding more operations to that type would be illegal according to the Ada
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-- Reference Manual. (This is the reason why the signals sets below are
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-- implemented as visible arrays rather than functions.)
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with System.OS_Interface;
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package System.Interrupt_Management is
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pragma Preelaborate;
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type Interrupt_Mask is limited private;
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type Interrupt_ID is new System.OS_Interface.Signal;
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type Interrupt_Set is array (Interrupt_ID) of Boolean;
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-- The following objects serve as constants, but are initialized in the
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-- body to aid portability. This permits us to use more portable names for
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-- interrupts, where distinct names may map to the same interrupt ID
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-- value. For example, suppose SIGRARE is a signal that is not defined on
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-- all systems, but is always reserved when it is defined. If we have the
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-- convention that ID zero is not used for any "real" signals, and SIGRARE
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-- = 0 when SIGRARE is not one of the locally supported signals, we can
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-- write:
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-- Reserved (SIGRARE) := true;
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-- Then the initialization code will be portable.
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Abort_Task_Interrupt : Interrupt_ID;
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-- The interrupt that is used to implement task abort, if an interrupt is
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-- used for that purpose. This is one of the reserved interrupts.
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Keep_Unmasked : Interrupt_Set := (others => False);
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-- Keep_Unmasked (I) is true iff the interrupt I is one that must be kept
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-- unmasked at all times, except (perhaps) for short critical sections.
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-- This includes interrupts that are mapped to exceptions (see
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-- System.Interrupt_Exceptions.Is_Exception), but may also include
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-- interrupts (e.g. timer) that need to be kept unmasked for other
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-- reasons. Where interrupts are implemented as OS signals, and signal
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-- masking is per-task, the interrupt should be unmasked in ALL TASKS.
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Reserve : Interrupt_Set := (others => False);
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-- Reserve (I) is true iff the interrupt I is one that cannot be permitted
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-- to be attached to a user handler. The possible reasons are many. For
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-- example it may be mapped to an exception used to implement task abort.
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Keep_Masked : Interrupt_Set := (others => False);
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-- Keep_Masked (I) is true iff the interrupt I must always be masked.
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-- Where interrupts are implemented as OS signals, and signal masking is
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-- per-task, the interrupt should be masked in ALL TASKS. There might not
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-- be any interrupts in this class, depending on the environment. For
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-- example, if interrupts are OS signals and signal masking is per-task,
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-- use of the sigwait operation requires the signal be masked in all tasks.
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procedure Initialize;
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-- Initialize the various variables defined in this package.
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-- This procedure must be called before accessing any object from this
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-- package and can be called multiple times.
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private
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use type System.OS_Interface.unsigned_long;
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type Interrupt_Mask is new System.OS_Interface.sigset_t;
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-- Interrupts on VMS are implemented with a mailbox. A QIO read is
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-- registered on the Rcv channel and the interrupt occurs by registering
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-- a QIO write on the Snd channel. The maximum number of pending
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-- interrupts is arbitrarily set at 1000. One nice feature of using
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-- a mailbox is that it is trivially extendable to cross process
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-- interrupts.
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Rcv_Interrupt_Chan : System.OS_Interface.unsigned_short := 0;
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Snd_Interrupt_Chan : System.OS_Interface.unsigned_short := 0;
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Interrupt_Mailbox : Interrupt_ID := 0;
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Interrupt_Bufquo : System.OS_Interface.unsigned_long :=
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1000 * (Interrupt_ID'Size / 8);
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end System.Interrupt_Management;
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