gcc/ada/s-intman.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
   4 --                                                                          --
   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         --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005 Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package encapsulates and centralizes information about all uses of
  35 --  interrupts (or signals), including the target-dependent mapping of
  36 --  interrupts (or signals) to exceptions.
  37
  38 --  Unlike the original design, System.Interrupt_Management can only be used
  39 --  for tasking systems.
  40
  41 --  PLEASE DO NOT remove the Elaborate_Body pragma from this package.
  42 --  Elaboration of this package should happen early, as most other
  43 --  initializations depend on it. Forcing immediate elaboration of the body
  44 --  also helps to enforce the design assumption that this is a second-level
  45 --  package, just one level above System.OS_Interface with no
  46 --  cross-dependencies.
  47
  48 --  PLEASE DO NOT put any subprogram declarations with arguments of type
  49 --  Interrupt_ID into the visible part of this package. The type Interrupt_ID
  50 --  is used to derive the type in Ada.Interrupts, and adding more operations
  51 --  to that type would be illegal according to the Ada Reference Manual. This
  52 --  is the reason why the signals sets are implemeneted using visible arrays
  53 --  rather than functions.
  54
  55 with System.OS_Interface;
  56 --  used for sigset_t
  57
  58 with Interfaces.C;
  59 --  used for int
  60
  61 package System.Interrupt_Management is
  62
  63    pragma Elaborate_Body;
  64
  65    type Interrupt_Mask is limited private;
  66
  67    type Interrupt_ID is new Interfaces.C.int
  68      range 0 .. System.OS_Interface.Max_Interrupt;
  69
  70    type Interrupt_Set is array (Interrupt_ID) of Boolean;
  71
  72    --  The following objects serve as constants, but are initialized in the
  73    --  body to aid portability. This permits us to use more portable names for
  74    --  interrupts, where distinct names may map to the same interrupt ID
  75    --  value.
  76
  77    --  For example, suppose SIGRARE is a signal that is not defined on all
  78    --  systems, but is always reserved when it is defined. If we have the
  79    --  convention that ID zero is not used for any "real" signals, and SIGRARE
  80    --  = 0 when SIGRARE is not one of the locally supported signals, we can
  81    --  write
  82
  83    --     Reserved (SIGRARE) := True;
  84
  85    --  and the initialization code will be portable.
  86
  87    Abort_Task_Interrupt : Interrupt_ID;
  88    --  The interrupt that is used to implement task abort if an interrupt is
  89    --  used for that purpose. This is one of the reserved interrupts.
  90
  91    Keep_Unmasked : Interrupt_Set := (others => False);
  92    --  Keep_Unmasked (I) is true iff the interrupt I is one that must that
  93    --  must be kept unmasked at all times, except (perhaps) for short critical
  94    --  sections. This includes interrupts that are mapped to exceptions (see
  95    --  System.Interrupt_Exceptions.Is_Exception), but may also include
  96    --  interrupts (e.g. timer) that need to be kept unmasked for other
  97    --  reasons. Where interrupts are implemented as OS signals, and signal
  98    --  masking is per-task, the interrupt should be unmasked in ALL TASKS.
  99
 100    Reserve : Interrupt_Set := (others => False);
 101    --  Reserve (I) is true iff the interrupt I is one that cannot be permitted
 102    --  to be attached to a user handler. The possible reasons are many. For
 103    --  example, it may be mapped to an exception used to implement task abort,
 104    --  or used to implement time delays.
 105
 106    procedure Initialize_Interrupts;
 107    --  On systems where there is no signal inheritance between tasks (e.g
 108    --  VxWorks, GNU/LinuxThreads), this procedure is used to initialize
 109    --  interrupts handling in each task. Otherwise this function should only
 110    --  be called by initialize in this package body.
 111
 112 private
 113    type Interrupt_Mask is new System.OS_Interface.sigset_t;
 114    --  In some implementations Interrupt_Mask can be represented as a linked
 115    --  list.
 116
 117 end System.Interrupt_Management;