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) 1992-2003 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
  35 --  uses of interrupts (or signals), including the target-dependent
  36 --  mapping of interrupts (or signals) to exceptions.
  37
  38 --  Unlike the original design, System.Interrupt_Management can only
  39 --  be used 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
  44 --  the body also helps to enforce the design assumption that this
  45 --  is a second-level package, just one level above System.OS_Interface
  46 --  with no cross-dependencies.
  47
  48 --  PLEASE DO NOT put any subprogram declarations with arguments of
  49 --  type Interrupt_ID into the visible part of this package. The type
  50 --  Interrupt_ID is used to derive the type in Ada.Interrupts, and
  51 --  adding more operations to that type would be illegal according
  52 --  to the Ada Reference Manual. This is the reason why the signals
  53 --  sets are implemeneted using visible arrays 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
  73    --  in the body to aid portability.  This permits us to use more
  74    --  portable names for interrupts, where distinct names may map to
  75    --  the same interrupt ID value.
  76    --
  77    --  For example, suppose SIGRARE is a signal that is not defined on
  78    --  all systems, but is always reserved when it is defined. If we
  79    --  have the convention that ID zero is not used for any "real"
  80    --  signals, and SIGRARE = 0 when SIGRARE is not one of the locally
  81    --  supported signals, we can write
  82    --     Reserved (SIGRARE) := true;
  83    --  and the initialization code will be portable.
  84
  85    Abort_Task_Interrupt : Interrupt_ID;
  86    --  The interrupt that is used to implement task abortion if
  87    --  an interrupt is used for that purpose. This is one of the
  88    --  reserved interrupts.
  89
  90    Keep_Unmasked : Interrupt_Set := (others => False);
  91    --  Keep_Unmasked (I) is true iff the interrupt I is one that must
  92    --  that must be kept unmasked at all times, except (perhaps) for
  93    --  short critical sections. This includes interrupts that are
  94    --  mapped to exceptions (see System.Interrupt_Exceptions.Is_Exception),
  95    --  but may also include interrupts (e.g. timer) that need to be kept
  96    --  unmasked for other reasons. Where interrupts are implemented as
  97    --  OS signals, and signal masking is per-task, the interrupt should
  98    --  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
 102    --  permitted to be attached to a user handler. The possible reasons
 103    --  are many. For example, it may be mapped to an exception used to
 104    --  implement task abortion, 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
 110    --  only 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 implementation Interrupt_Mask can be represented
 115    --  as a linked list.
 116
 117 end System.Interrupt_Management;