gcc/ada/libgnat/s-atocou.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --               S Y S T E M . A T O M I C _ C O U N T E R S                --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2011-2018, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT 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 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT 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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is version of the package, for use on platforms where this capability
  33 --  is not supported. All Atomic_Counter operations raises Program_Error,
  34 --  Atomic_Unsigned operations processed in non-atomic manner.
  35
  36 package body System.Atomic_Counters is
  37
  38    ---------------
  39    -- Decrement --
  40    ---------------
  41
  42    function Decrement (Item : in out Atomic_Counter) return Boolean is
  43    begin
  44       raise Program_Error;
  45       return False;
  46    end Decrement;
  47
  48    function Decrement (Item : aliased in out Atomic_Unsigned) return Boolean is
  49    begin
  50       --  Could not use Item := Item - 1; because it is disabled in spec.
  51       Item := Atomic_Unsigned'Pred (Item);
  52       return Item = 0;
  53    end Decrement;
  54
  55    procedure Decrement (Item : aliased in out Atomic_Unsigned) is
  56    begin
  57       Item := Atomic_Unsigned'Pred (Item);
  58    end Decrement;
  59
  60    ---------------
  61    -- Increment --
  62    ---------------
  63
  64    procedure Increment (Item : in out Atomic_Counter) is
  65    begin
  66       raise Program_Error;
  67    end Increment;
  68
  69    procedure Increment (Item : aliased in out Atomic_Unsigned) is
  70    begin
  71       Item := Atomic_Unsigned'Succ (Item);
  72    end Increment;
  73
  74    ----------------
  75    -- Initialize --
  76    ----------------
  77
  78    procedure Initialize (Item : out Atomic_Counter) is
  79    begin
  80       raise Program_Error;
  81    end Initialize;
  82
  83    ------------
  84    -- Is_One --
  85    ------------
  86
  87    function Is_One (Item : Atomic_Counter) return Boolean is
  88    begin
  89       raise Program_Error;
  90       return False;
  91    end Is_One;
  92
  93 end System.Atomic_Counters;