gcc/ada/s-addope.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --             S Y S T E M . A D D R E S S _ O P E R A T I O N S            --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2004-2007, 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 --  This package provides arithmetic and logical operations on type Address.
  35 --  It is intended for use by other packages in the System hierarchy. For
  36 --  applications requiring this capability, see System.Storage_Elements or
  37 --  the operations introduced in System.Aux_DEC;
  38
  39 --  The reason we need this package is that arithmetic operations may not
  40 --  be available in the case where type Address is non-private and the
  41 --  operations have been made abstract in the spec of System (to avoid
  42 --  inappropriate use by applications programs). In addition, the logical
  43 --  operations may not be available if type Address is a signed integer.
  44
  45 pragma Warnings (Off);
  46 pragma Compiler_Unit;
  47 pragma Warnings (On);
  48
  49 package System.Address_Operations is
  50    pragma Pure;
  51
  52    --  The semantics of the arithmetic operations are those that apply to
  53    --  a modular type with the same length as Address, i.e. they provide
  54    --  twos complement wrap around arithmetic treating the address value
  55    --  as an unsigned value, with no overflow checking.
  56
  57    --  Note that we do not use the infix names for these operations to
  58    --  avoid problems with ambiguities coming from declarations in package
  59    --  Standard (which may or may not be visible depending on the exact
  60    --  form of the declaration of type System.Address).
  61
  62    --  For addition, subtraction, and multiplication, the effect of overflow
  63    --  is 2's complement wrapping (as though the type Address were unsigned).
  64
  65    --  For division and modulus operations, the caller is responsible for
  66    --  ensuring that the Right argument is non-zero, and the effect of the
  67    --  call is not specified if a zero argument is passed.
  68
  69    function AddA (Left, Right : Address) return Address;
  70    function SubA (Left, Right : Address) return Address;
  71    function MulA (Left, Right : Address) return Address;
  72    function DivA (Left, Right : Address) return Address;
  73    function ModA (Left, Right : Address) return Address;
  74
  75    --  The semantics of the logical operations are those that apply to
  76    --  a modular type with the same length as Address, i.e. they provide
  77    --  bit-wise operations on all bits of the value (including the sign
  78    --  bit if Address is a signed integer type).
  79
  80    function AndA (Left, Right : Address) return Address;
  81    function OrA  (Left, Right : Address) return Address;
  82
  83    pragma Inline_Always (AddA);
  84    pragma Inline_Always (SubA);
  85    pragma Inline_Always (MulA);
  86    pragma Inline_Always (DivA);
  87    pragma Inline_Always (ModA);
  88    pragma Inline_Always (AndA);
  89    pragma Inline_Always (OrA);
  90
  91 end System.Address_Operations;