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) 1992-2007, 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 2,  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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 pragma Warnings (Off);
  35 pragma Compiler_Unit;
  36 pragma Warnings (On);
  37
  38 with Ada.Unchecked_Conversion;
  39
  40 package body System.Storage_Elements is
  41
  42    pragma Suppress (All_Checks);
  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    function To_Integer (Value : Address) return Integer_Address is
  55    begin
  56       return Integer_Address (Value);
  57    end To_Integer;
  58
  59    function To_Address (Value : Integer_Address) return Address is
  60    begin
  61       return Address (Value);
  62    end To_Address;
  63
  64    --  Address arithmetic
  65
  66    function "+" (Left : Address; Right : Storage_Offset) return Address is
  67    begin
  68       return To_Address (To_Integer (Left) + To_Integer (To_Address (Right)));
  69    end "+";
  70
  71    function "+" (Left : Storage_Offset; Right : Address) return Address is
  72    begin
  73       return To_Address (To_Integer (To_Address (Left)) + To_Integer (Right));
  74    end "+";
  75
  76    function "-" (Left : Address; Right : Storage_Offset) return Address is
  77    begin
  78       return To_Address (To_Integer (Left) - To_Integer (To_Address (Right)));
  79    end "-";
  80
  81    function "-" (Left, Right : Address) return Storage_Offset is
  82    begin
  83       return To_Offset (To_Address (To_Integer (Left) - To_Integer (Right)));
  84    end "-";
  85
  86    function "mod"
  87      (Left  : Address;
  88       Right : Storage_Offset) return Storage_Offset
  89    is
  90    begin
  91       if Right > 0 then
  92          return Storage_Offset
  93            (To_Integer (Left) mod Integer_Address (Right));
  94
  95          --  The negative case makes no sense since it is a case of a mod where
  96          --  the left argument is unsigned and the right argument is signed. In
  97          --  accordance with the (spirit of the) permission of RM 13.7.1(16),
  98          --  we raise CE, and also include the zero case here. Yes, the RM says
  99          --  PE, but this really is so obviously more like a constraint error.
 100
 101       else
 102          raise Constraint_Error;
 103       end if;
 104    end "mod";
 105 end System.Storage_Elements;