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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--               S Y S T E M . S T O R A G E _ E L E M E N T S              --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2009, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

pragma Compiler_Unit;

with Ada.Unchecked_Conversion;

package body System.Storage_Elements is

   pragma Suppress (All_Checks);

   --  Conversion to/from address

   --  Note qualification below of To_Address to avoid ambiguities on VMS

   function To_Address is

     new Ada.Unchecked_Conversion (Storage_Offset, Address);

   function To_Offset  is

     new Ada.Unchecked_Conversion (Address, Storage_Offset);

   --  Conversion to/from integers

   --  These functions must be place first because they are inlined_always

   --  and are used and inlined in other subprograms defined in this unit.

   ----------------

   -- To_Address --

   ----------------

   function To_Address (Value : Integer_Address) return Address is

   begin

      return Address (Value);

   end To_Address;

   ----------------

   -- To_Integer --

   ----------------

   function To_Integer (Value : Address) return Integer_Address is

   begin

      return Integer_Address (Value);

   end To_Integer;

   --  Address arithmetic

   ---------

   -- "+" --

   ---------

   function "+" (Left : Address; Right : Storage_Offset) return Address is

   begin

      return Storage_Elements.To_Address

        (To_Integer (Left) + To_Integer (To_Address (Right)));

   end "+";

   function "+" (Left : Storage_Offset; Right : Address) return Address is

   begin

      return Storage_Elements.To_Address

        (To_Integer (To_Address (Left)) + To_Integer (Right));

   end "+";

   ---------

   -- "-" --

   ---------

   function "-" (Left : Address; Right : Storage_Offset) return Address is

   begin

      return Storage_Elements.To_Address

        (To_Integer (Left) - To_Integer (To_Address (Right)));

   end "-";

   function "-" (Left, Right : Address) return Storage_Offset is

   begin

      return To_Offset (Storage_Elements.To_Address

                         (To_Integer (Left) - To_Integer (Right)));

   end "-";

   -----------

   -- "mod" --

   -----------

   function "mod"

     (Left  : Address;

      Right : Storage_Offset) return Storage_Offset

   is

   begin

      if Right > 0 then

         return Storage_Offset

           (To_Integer (Left) mod Integer_Address (Right));

         --  The negative case makes no sense since it is a case of a mod where

         --  the left argument is unsigned and the right argument is signed. In

         --  accordance with the (spirit of the) permission of RM 13.7.1(16),

         --  we raise CE, and also include the zero case here. Yes, the RM says

         --  PE, but this really is so obviously more like a constraint error.

      else

         raise Constraint_Error;

      end if;

   end "mod";

end System.Storage_Elements;