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    --  Conversion to/from address
  41
  42    --  Note qualification below of To_Address to avoid ambiguities on VMS
  43
  44    function To_Address is
  45      new Ada.Unchecked_Conversion (Storage_Offset, Address);
  46    function To_Offset  is
  47      new Ada.Unchecked_Conversion (Address, Storage_Offset);
  48
  49    --  Conversion to/from integers
  50
  51    --  These functions must be place first because they are inlined_always
  52    --  and are used and inlined in other subprograms defined in this unit.
  53
  54    ----------------
  55    -- To_Address --
  56    ----------------
  57
  58    function To_Address (Value : Integer_Address) return Address is
  59    begin
  60       return Address (Value);
  61    end To_Address;
  62
  63    ----------------
  64    -- To_Integer --
  65    ----------------
  66
  67    function To_Integer (Value : Address) return Integer_Address is
  68    begin
  69       return Integer_Address (Value);
  70    end To_Integer;
  71
  72    --  Address arithmetic
  73
  74    ---------
  75    -- "+" --
  76    ---------
  77
  78    function "+" (Left : Address; Right : Storage_Offset) return Address is
  79    begin
  80       return Storage_Elements.To_Address
  81         (To_Integer (Left) + To_Integer (To_Address (Right)));
  82    end "+";
  83
  84    function "+" (Left : Storage_Offset; Right : Address) return Address is
  85    begin
  86       return Storage_Elements.To_Address
  87         (To_Integer (To_Address (Left)) + To_Integer (Right));
  88    end "+";
  89
  90    ---------
  91    -- "-" --
  92    ---------
  93
  94    function "-" (Left : Address; Right : Storage_Offset) return Address is
  95    begin
  96       return Storage_Elements.To_Address
  97         (To_Integer (Left) - To_Integer (To_Address (Right)));
  98    end "-";
  99
 100    function "-" (Left, Right : Address) return Storage_Offset is
 101    begin
 102       return To_Offset (Storage_Elements.To_Address
 103                          (To_Integer (Left) - To_Integer (Right)));
 104    end "-";
 105
 106    -----------
 107    -- "mod" --
 108    -----------
 109
 110    function "mod"
 111      (Left  : Address;
 112       Right : Storage_Offset) return Storage_Offset
 113    is
 114    begin
 115       if Right > 0 then
 116          return Storage_Offset
 117            (To_Integer (Left) mod Integer_Address (Right));
 118
 119          --  The negative case makes no sense since it is a case of a mod where
 120          --  the left argument is unsigned and the right argument is signed. In
 121          --  accordance with the (spirit of the) permission of RM 13.7.1(16),
 122          --  we raise CE, and also include the zero case here. Yes, the RM says
 123          --  PE, but this really is so obviously more like a constraint error.
 124
 125       else
 126          raise Constraint_Error;
 127       end if;
 128    end "mod";
 129
 130 end System.Storage_Elements;