88 lines
4.8 KiB
Ada
88 lines
4.8 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . A D D R E S S _ O P E R A T I O N S --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 2004-2013, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This package provides arithmetic and logical operations on type Address.
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-- It is intended for use by other packages in the System hierarchy. For
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-- applications requiring this capability, see System.Storage_Elements or
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-- the operations introduced in System.Aux_DEC;
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-- The reason we need this package is that arithmetic operations may not
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-- be available in the case where type Address is non-private and the
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-- operations have been made abstract in the spec of System (to avoid
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-- inappropriate use by applications programs). In addition, the logical
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-- operations may not be available if type Address is a signed integer.
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pragma Compiler_Unit_Warning;
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package System.Address_Operations is
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pragma Pure;
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-- The semantics of the arithmetic operations are those that apply to
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-- a modular type with the same length as Address, i.e. they provide
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-- twos complement wrap around arithmetic treating the address value
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-- as an unsigned value, with no overflow checking.
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-- Note that we do not use the infix names for these operations to
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-- avoid problems with ambiguities coming from declarations in package
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-- Standard (which may or may not be visible depending on the exact
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-- form of the declaration of type System.Address).
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-- For addition, subtraction, and multiplication, the effect of overflow
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-- is 2's complement wrapping (as though the type Address were unsigned).
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-- For division and modulus operations, the caller is responsible for
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-- ensuring that the Right argument is non-zero, and the effect of the
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-- call is not specified if a zero argument is passed.
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function AddA (Left, Right : Address) return Address;
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function SubA (Left, Right : Address) return Address;
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function MulA (Left, Right : Address) return Address;
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function DivA (Left, Right : Address) return Address;
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function ModA (Left, Right : Address) return Address;
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-- The semantics of the logical operations are those that apply to
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-- a modular type with the same length as Address, i.e. they provide
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-- bit-wise operations on all bits of the value (including the sign
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-- bit if Address is a signed integer type).
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function AndA (Left, Right : Address) return Address;
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function OrA (Left, Right : Address) return Address;
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pragma Inline_Always (AddA);
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pragma Inline_Always (SubA);
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pragma Inline_Always (MulA);
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pragma Inline_Always (DivA);
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pragma Inline_Always (ModA);
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pragma Inline_Always (AndA);
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pragma Inline_Always (OrA);
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end System.Address_Operations;
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