gcc/ada/s-stoele.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --               S Y S T E M . S T O R A G E _ E L E M E N T S              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2009, 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 pragma Compiler_Unit;
  33
  34 with Ada.Unchecked_Conversion;
  35
  36 package body System.Storage_Elements is
  37
  38    pragma Suppress (All_Checks);
  39
  40    function To_Address is
  41      new Ada.Unchecked_Conversion (Storage_Offset, Address);
  42    function To_Offset  is
  43      new Ada.Unchecked_Conversion (Address, Storage_Offset);
  44
  45    --  Conversion to/from integers
  46
  47    --  These functions must be place first because they are inlined_always
  48    --  and are used and inlined in other subprograms defined in this unit.
  49
  50    function To_Integer (Value : Address) return Integer_Address is
  51    begin
  52       return Integer_Address (Value);
  53    end To_Integer;
  54
  55    function To_Address (Value : Integer_Address) return Address is
  56    begin
  57       return Address (Value);
  58    end To_Address;
  59
  60    --  Address arithmetic
  61
  62    function "+" (Left : Address; Right : Storage_Offset) return Address is
  63    begin
  64       return To_Address (To_Integer (Left) + To_Integer (To_Address (Right)));
  65    end "+";
  66
  67    function "+" (Left : Storage_Offset; Right : Address) return Address is
  68    begin
  69       return To_Address (To_Integer (To_Address (Left)) + To_Integer (Right));
  70    end "+";
  71
  72    function "-" (Left : Address; Right : Storage_Offset) return Address is
  73    begin
  74       return To_Address (To_Integer (Left) - To_Integer (To_Address (Right)));
  75    end "-";
  76
  77    function "-" (Left, Right : Address) return Storage_Offset is
  78    begin
  79       return To_Offset (To_Address (To_Integer (Left) - To_Integer (Right)));
  80    end "-";
  81
  82    function "mod"
  83      (Left  : Address;
  84       Right : Storage_Offset) return Storage_Offset
  85    is
  86    begin
  87       if Right > 0 then
  88          return Storage_Offset
  89            (To_Integer (Left) mod Integer_Address (Right));
  90
  91          --  The negative case makes no sense since it is a case of a mod where
  92          --  the left argument is unsigned and the right argument is signed. In
  93          --  accordance with the (spirit of the) permission of RM 13.7.1(16),
  94          --  we raise CE, and also include the zero case here. Yes, the RM says
  95          --  PE, but this really is so obviously more like a constraint error.
  96
  97       else
  98          raise Constraint_Error;
  99       end if;
 100    end "mod";
 101 end System.Storage_Elements;