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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 --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2021, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <>. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
-- This package encapsulates and centralizes information about all uses of
-- interrupts (or signals), including the target-dependent mapping of
-- interrupts (or signals) to exceptions.
-- Unlike the original design, System.Interrupt_Management can only be used
-- for tasking systems.
-- PLEASE DO NOT put any subprogram declarations with arguments of type
-- Interrupt_ID into the visible part of this package. The type Interrupt_ID
-- is used to derive the type in Ada.Interrupts, and adding more operations
-- to that type would be illegal according to the Ada Reference Manual. This
-- is the reason why the signals sets are implemented using visible arrays
-- rather than functions.
with System.OS_Interface;
with Interfaces.C;
package System.Interrupt_Management is
pragma Preelaborate;
type Interrupt_Mask is limited private;
type Interrupt_ID is new
range 0 .. System.OS_Interface.Max_Interrupt;
type Interrupt_Set is array (Interrupt_ID) of Boolean;
-- The following objects serve as constants, but are initialized in the
-- body to aid portability. This permits us to use more portable names for
-- interrupts, where distinct names may map to the same interrupt ID
-- value.
-- For example, suppose SIGRARE is a signal that is not defined on all
-- systems, but is always reserved when it is defined. If we have the
-- convention that ID zero is not used for any "real" signals, and SIGRARE
-- = 0 when SIGRARE is not one of the locally supported signals, we can
-- write:
-- Reserved (SIGRARE) := True;
-- and the initialization code will be portable.
Abort_Task_Interrupt : Interrupt_ID;
-- The interrupt that is used to implement task abort if an interrupt is
-- used for that purpose. This is one of the reserved interrupts.
Keep_Unmasked : Interrupt_Set := (others => False);
-- Keep_Unmasked (I) is true iff the interrupt I is one that must be kept
-- unmasked at all times, except (perhaps) for short critical sections.
-- This includes interrupts that are mapped to exceptions (see
-- System.Interrupt_Exceptions.Is_Exception), but may also include
-- interrupts (e.g. timer) that need to be kept unmasked for other
-- reasons. Where interrupts are implemented as OS signals, and signal
-- masking is per-task, the interrupt should be unmasked in ALL TASKS.
Reserve : Interrupt_Set := (others => False);
-- Reserve (I) is true iff the interrupt I is one that cannot be permitted
-- to be attached to a user handler. The possible reasons are many. For
-- example, it may be mapped to an exception used to implement task abort,
-- or used to implement time delays.
procedure Initialize;
-- Initialize the various variables defined in this package. This procedure
-- must be called before accessing any object from this package, and can be
-- called multiple times.
type Interrupt_Mask is new System.OS_Interface.sigset_t;
-- In some implementations Interrupt_Mask is represented as a linked list
procedure Adjust_Context_For_Raise
(Signo : System.OS_Interface.Signal;
Ucontext : System.Address);
pragma Import
(C, Adjust_Context_For_Raise, "__gnat_adjust_context_for_raise");
-- Target specific hook performing adjustments to the signal's machine
-- context, to be called before an exception may be raised from a signal
-- handler. This service is provided by init.c, together with the
-- non-tasking signal handler.
end System.Interrupt_Management;