------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                  S Y S T E M . A D D R E S S _ I M A G E                 --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--   Copyright (C) 1992,1993,1994,1995,1996 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 2,  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.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
-- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
-- Boston, MA 02110-1301, USA.                                              --
--                                                                          --
-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
-- this  unit  does not  by itself cause  the resulting  executable  to  be --
-- covered  by the  GNU  General  Public  License.  This exception does not --
-- however invalidate  any other reasons why  the executable file  might be --
-- covered by the  GNU Public License.                                      --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Unchecked_Conversion;

function System.Address_Image (A : Address) return String is

   Result  : String (1 .. 2 * Address'Size / Storage_Unit);

   type Byte is mod 2 ** 8;
   for Byte'Size use 8;

   Hexdigs :
     constant array (Byte range 0 .. 15) of Character := "0123456789ABCDEF";

   type Bytes is array (1 .. Address'Size / Storage_Unit) of Byte;
   for Bytes'Size use Address'Size;

   function To_Bytes is new Unchecked_Conversion (Address, Bytes);

   Byte_Sequence : constant Bytes := To_Bytes (A);

   LE : constant := Standard'Default_Bit_Order;
   BE : constant := 1 - LE;
   --  Set to 1/0 for True/False for Little-Endian/Big-Endian

   Start : constant Natural := BE * (1) + LE * (Bytes'Length);
   Incr  : constant Integer := BE * (1) + LE * (-1);
   --  Start and increment for accessing characters of address string

   Ptr : Natural;
   --  Scan address string

begin
   Ptr := Start;
   for N in Bytes'Range loop
      Result (2 * N - 1) := Hexdigs (Byte_Sequence (Ptr) / 16);
      Result (2 * N)     := Hexdigs (Byte_Sequence (Ptr) mod 16);
      Ptr := Ptr + Incr;
   end loop;

   return Result;

end System.Address_Image;