gcc/ada/s-intman.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT 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,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, 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 put any subprogram declarations with arguments of type
  42 --  Interrupt_ID into the visible part of this package. The type Interrupt_ID
  43 --  is used to derive the type in Ada.Interrupts, and adding more operations
  44 --  to that type would be illegal according to the Ada Reference Manual. This
  45 --  is the reason why the signals sets are implemeneted using visible arrays
  46 --  rather than functions.
  47
  48 with System.OS_Interface;
  49 --  used for sigset_t
  50
  51 with Interfaces.C;
  52 --  used for int
  53
  54 package System.Interrupt_Management is
  55    pragma Preelaborate;
  56
  57    type Interrupt_Mask is limited private;
  58
  59    type Interrupt_ID is new Interfaces.C.int
  60      range 0 .. System.OS_Interface.Max_Interrupt;
  61
  62    type Interrupt_Set is array (Interrupt_ID) of Boolean;
  63
  64    --  The following objects serve as constants, but are initialized in the
  65    --  body to aid portability. This permits us to use more portable names for
  66    --  interrupts, where distinct names may map to the same interrupt ID
  67    --  value.
  68
  69    --  For example, suppose SIGRARE is a signal that is not defined on all
  70    --  systems, but is always reserved when it is defined. If we have the
  71    --  convention that ID zero is not used for any "real" signals, and SIGRARE
  72    --  = 0 when SIGRARE is not one of the locally supported signals, we can
  73    --  write
  74
  75    --     Reserved (SIGRARE) := True;
  76
  77    --  and the initialization code will be portable.
  78
  79    Abort_Task_Interrupt : Interrupt_ID;
  80    --  The interrupt that is used to implement task abort if an interrupt is
  81    --  used for that purpose. This is one of the reserved interrupts.
  82
  83    Keep_Unmasked : Interrupt_Set := (others => False);
  84    --  Keep_Unmasked (I) is true iff the interrupt I is one that must that
  85    --  must be kept unmasked at all times, except (perhaps) for short critical
  86    --  sections. This includes interrupts that are mapped to exceptions (see
  87    --  System.Interrupt_Exceptions.Is_Exception), but may also include
  88    --  interrupts (e.g. timer) that need to be kept unmasked for other
  89    --  reasons. Where interrupts are implemented as OS signals, and signal
  90    --  masking is per-task, the interrupt should be unmasked in ALL TASKS.
  91
  92    Reserve : Interrupt_Set := (others => False);
  93    --  Reserve (I) is true iff the interrupt I is one that cannot be permitted
  94    --  to be attached to a user handler. The possible reasons are many. For
  95    --  example, it may be mapped to an exception used to implement task abort,
  96    --  or used to implement time delays.
  97
  98    procedure Initialize;
  99    --  Initialize the various variables defined in this package.
 100    --  This procedure must be called before accessing any object from this
 101    --  package, and can be called multiple times.
 102
 103 private
 104    type Interrupt_Mask is new System.OS_Interface.sigset_t;
 105    --  In some implementations Interrupt_Mask can be represented as a linked
 106    --  list.
 107
 108 end System.Interrupt_Management;