------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- 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) 1991-2005 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 2, or (at your option) any later ver- -- -- sion. GNARL is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNARL; see file COPYING. If not, write -- -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- -- Boston, MA 02110-1301, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is the Alpha/VMS version of this package -- This package encapsulates and centralizes information about all uses of -- interrupts (or signals), including the target-dependent mapping of -- interrupts (or signals) to exceptions. -- PLEASE DO NOT add any with-clauses to this package -- 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 below are -- implemented as visible arrays rather than functions.) with System.OS_Interface; -- used for Signal -- sigset_t package System.Interrupt_Management is pragma Preelaborate; type Interrupt_Mask is limited private; type Interrupt_ID is new System.OS_Interface.Signal; 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; -- Then 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. Keep_Masked : Interrupt_Set := (others => False); -- Keep_Masked (I) is true iff the interrupt I must always be masked. -- Where interrupts are implemented as OS signals, and signal masking is -- per-task, the interrupt should be masked in ALL TASKS. There might not -- be any interrupts in this class, depending on the environment. For -- example, if interrupts are OS signals and signal masking is per-task, -- use of the sigwait operation requires the signal be masked in all tasks. 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. private use type System.OS_Interface.unsigned_long; type Interrupt_Mask is new System.OS_Interface.sigset_t; -- Interrupts on VMS are implemented with a mailbox. A QIO read is -- registered on the Rcv channel and the interrupt occurs by registering -- a QIO write on the Snd channel. The maximum number of pending -- interrupts is arbitrarily set at 1000. One nice feature of using -- a mailbox is that it is trivially extendable to cross process -- interrupts. Rcv_Interrupt_Chan : System.OS_Interface.unsigned_short := 0; Snd_Interrupt_Chan : System.OS_Interface.unsigned_short := 0; Interrupt_Mailbox : Interrupt_ID := 0; Interrupt_Bufquo : System.OS_Interface.unsigned_long := 1000 * (Interrupt_ID'Size / 8); end System.Interrupt_Management;