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--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--             S Y S T E M . A D D R E S S _ O P E R A T I O N S            --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 2004-2009, 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.      --

--                                                                          --

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--  This package provides arithmetic and logical operations on type Address.

--  It is intended for use by other packages in the System hierarchy. For

--  applications requiring this capability, see System.Storage_Elements or

--  the operations introduced in System.Aux_DEC;

--  The reason we need this package is that arithmetic operations may not

--  be available in the case where type Address is non-private and the

--  operations have been made abstract in the spec of System (to avoid

--  inappropriate use by applications programs). In addition, the logical

--  operations may not be available if type Address is a signed integer.

pragma Compiler_Unit;

package System.Address_Operations is

   pragma Pure;

   --  The semantics of the arithmetic operations are those that apply to

   --  a modular type with the same length as Address, i.e. they provide

   --  twos complement wrap around arithmetic treating the address value

   --  as an unsigned value, with no overflow checking.

   --  Note that we do not use the infix names for these operations to

   --  avoid problems with ambiguities coming from declarations in package

   --  Standard (which may or may not be visible depending on the exact

   --  form of the declaration of type System.Address).

   --  For addition, subtraction, and multiplication, the effect of overflow

   --  is 2's complement wrapping (as though the type Address were unsigned).

   --  For division and modulus operations, the caller is responsible for

   --  ensuring that the Right argument is non-zero, and the effect of the

   --  call is not specified if a zero argument is passed.

   function AddA (Left, Right : Address) return Address;

   function SubA (Left, Right : Address) return Address;

   function MulA (Left, Right : Address) return Address;

   function DivA (Left, Right : Address) return Address;

   function ModA (Left, Right : Address) return Address;

   --  The semantics of the logical operations are those that apply to

   --  a modular type with the same length as Address, i.e. they provide

   --  bit-wise operations on all bits of the value (including the sign

   --  bit if Address is a signed integer type).

   function AndA (Left, Right : Address) return Address;

   function OrA  (Left, Right : Address) return Address;

   pragma Inline_Always (AddA);

   pragma Inline_Always (SubA);

   pragma Inline_Always (MulA);

   pragma Inline_Always (DivA);

   pragma Inline_Always (ModA);

   pragma Inline_Always (AndA);

   pragma Inline_Always (OrA);

end System.Address_Operations;