1 ------------------------------------------------------------------------------
3 -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- 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 --
10 -- Copyright (C) 1991-2001 Free Software Foundation, Inc. --
12 -- GNARL is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNARL; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNARL was developed by the GNARL team at Florida State University. It is --
31 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
32 -- State University (http://www.gnat.com). --
34 ------------------------------------------------------------------------------
36 -- This is the Alpha/VMS version of this package.
38 -- This package encapsulates and centralizes information about
39 -- all uses of interrupts (or signals), including the
40 -- target-dependent mapping of interrupts (or signals) to exceptions.
42 -- PLEASE DO NOT add any with-clauses to this package.
43 -- This is designed to work for both tasking and non-tasking systems,
44 -- without pulling in any of the tasking support.
46 -- PLEASE DO NOT remove the Elaborate_Body pragma from this package.
47 -- Elaboration of this package should happen early, as most other
48 -- initializations depend on it.
49 -- Forcing immediate elaboration of the body also helps to enforce
50 -- the design assumption that this is a second-level
51 -- package, just one level above System.OS_Interface, with no
54 -- PLEASE DO NOT put any subprogram declarations with arguments of
55 -- type Interrupt_ID into the visible part of this package.
56 -- The type Interrupt_ID is used to derive the type in Ada.Interrupts,
57 -- and adding more operations to that type would be illegal according
58 -- to the Ada Reference Manual. (This is the reason why the signals sets
59 -- below are implemented as visible arrays rather than functions.)
61 with System
.OS_Interface
;
65 package System
.Interrupt_Management
is
67 pragma Elaborate_Body
;
69 type Interrupt_Mask
is limited private;
71 type Interrupt_ID
is new System
.OS_Interface
.Signal
;
73 type Interrupt_Set
is array (Interrupt_ID
) of Boolean;
75 -- The following objects serve as constants, but are initialized
76 -- in the body to aid portability. This permits us
77 -- to use more portable names for interrupts,
78 -- where distinct names may map to the same interrupt ID value.
79 -- For example, suppose SIGRARE is a signal that is not defined on
80 -- all systems, but is always reserved when it is defined.
81 -- If we have the convention that ID zero is not used for any "real"
82 -- signals, and SIGRARE = 0 when SIGRARE is not one of the locally
83 -- supported signals, we can write
84 -- Reserved (SIGRARE) := true;
85 -- and the initialization code will be portable.
87 Abort_Task_Interrupt
: Interrupt_ID
;
88 -- The interrupt that is used to implement task abortion,
89 -- if an interrupt is used for that purpose.
90 -- This is one of the reserved interrupts.
92 Keep_Unmasked
: Interrupt_Set
:= (others => False);
93 -- Keep_Unmasked (I) is true iff the interrupt I is
94 -- one that must be kept unmasked at all times,
95 -- except (perhaps) for short critical sections.
96 -- This includes interrupts that are mapped to exceptions
97 -- (see System.Interrupt_Exceptions.Is_Exception), but may also
98 -- include interrupts (e.g. timer) that need to be kept unmasked
100 -- Where interrupts are implemented as OS signals, and signal masking
101 -- is per-task, the interrupt should be unmasked in ALL TASKS.
103 Reserve
: Interrupt_Set
:= (others => False);
104 -- Reserve (I) is true iff the interrupt I is one that
105 -- cannot be permitted to be attached to a user handler.
106 -- The possible reasons are many. For example,
107 -- it may be mapped to an exception, used to implement task abortion,
108 -- or used to implement time delays.
110 Keep_Masked
: Interrupt_Set
:= (others => False);
111 -- Keep_Masked (I) is true iff the interrupt I must always be masked.
112 -- Where interrupts are implemented as OS signals, and signal masking
113 -- is per-task, the interrupt should be masked in ALL TASKS.
114 -- There might not be any interrupts in this class, depending on
115 -- the environment. For example, if interrupts are OS signals
116 -- and signal masking is per-task, use of the sigwait operation
117 -- requires the signal be masked in all tasks.
119 procedure Initialize_Interrupts
;
120 -- On systems where there is no signal inheritance between tasks (e.g
121 -- VxWorks, GNU/LinuxThreads), this procedure is used to initialize
122 -- interrupts handling in each task. Otherwise this function should
123 -- only be called by initialize in this package body.
127 use type System
.OS_Interface
.unsigned_long
;
129 type Interrupt_Mask
is new System
.OS_Interface
.sigset_t
;
131 -- Interrupts on VMS are implemented with a mailbox. A QIO read is
132 -- registered on the Rcv channel and the interrupt occurs by registering
133 -- a QIO write on the Snd channel. The maximum number of pending
134 -- interrupts is arbitrarily set at 1000. One nice feature of using
135 -- a mailbox is that it is trivially extendable to cross process
138 Rcv_Interrupt_Chan
: System
.OS_Interface
.unsigned_short
:= 0;
139 Snd_Interrupt_Chan
: System
.OS_Interface
.unsigned_short
:= 0;
140 Interrupt_Mailbox
: Interrupt_ID
:= 0;
141 Interrupt_Bufquo
: System
.OS_Interface
.unsigned_long
142 := 1000 * (Interrupt_ID
'Size / 8);
144 end System
.Interrupt_Management
;