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) 2004-2013, 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 3, 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. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNAT was originally developed by the GNAT team at New York University. -- 28-- Extensive contributions were provided by Ada Core Technologies Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This package provides arithmetic and logical operations on type Address. 33-- It is intended for use by other packages in the System hierarchy. For 34-- applications requiring this capability, see System.Storage_Elements or 35-- the operations introduced in System.Aux_DEC; 36 37-- The reason we need this package is that arithmetic operations may not 38-- be available in the case where type Address is non-private and the 39-- operations have been made abstract in the spec of System (to avoid 40-- inappropriate use by applications programs). In addition, the logical 41-- operations may not be available if type Address is a signed integer. 42 43pragma Compiler_Unit_Warning; 44 45package System.Address_Operations is 46 pragma Pure; 47 48 -- The semantics of the arithmetic operations are those that apply to 49 -- a modular type with the same length as Address, i.e. they provide 50 -- twos complement wrap around arithmetic treating the address value 51 -- as an unsigned value, with no overflow checking. 52 53 -- Note that we do not use the infix names for these operations to 54 -- avoid problems with ambiguities coming from declarations in package 55 -- Standard (which may or may not be visible depending on the exact 56 -- form of the declaration of type System.Address). 57 58 -- For addition, subtraction, and multiplication, the effect of overflow 59 -- is 2's complement wrapping (as though the type Address were unsigned). 60 61 -- For division and modulus operations, the caller is responsible for 62 -- ensuring that the Right argument is non-zero, and the effect of the 63 -- call is not specified if a zero argument is passed. 64 65 function AddA (Left, Right : Address) return Address; 66 function SubA (Left, Right : Address) return Address; 67 function MulA (Left, Right : Address) return Address; 68 function DivA (Left, Right : Address) return Address; 69 function ModA (Left, Right : Address) return Address; 70 71 -- The semantics of the logical operations are those that apply to 72 -- a modular type with the same length as Address, i.e. they provide 73 -- bit-wise operations on all bits of the value (including the sign 74 -- bit if Address is a signed integer type). 75 76 function AndA (Left, Right : Address) return Address; 77 function OrA (Left, Right : Address) return Address; 78 79 pragma Inline_Always (AddA); 80 pragma Inline_Always (SubA); 81 pragma Inline_Always (MulA); 82 pragma Inline_Always (DivA); 83 pragma Inline_Always (ModA); 84 pragma Inline_Always (AndA); 85 pragma Inline_Always (OrA); 86 87end System.Address_Operations; 88