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135 lines
6.2 KiB
HTML
135 lines
6.2 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Copyright (C) 1988-2018 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Funding Free Software", the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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"GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>Integers implementation (Using the GNU Compiler Collection (GCC))</title>
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<meta name="description" content="Integers implementation (Using the GNU Compiler Collection (GCC))">
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<meta name="keywords" content="Integers implementation (Using the GNU Compiler Collection (GCC))">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="C-Implementation.html#C-Implementation" rel="up" title="C Implementation">
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<link href="Floating-point-implementation.html#Floating-point-implementation" rel="next" title="Floating point implementation">
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<link href="Characters-implementation.html#Characters-implementation" rel="prev" title="Characters implementation">
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<style type="text/css">
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-->
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</style>
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</head>
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<body lang="en">
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<a name="Integers-implementation"></a>
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<div class="header">
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<p>
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Next: <a href="Floating-point-implementation.html#Floating-point-implementation" accesskey="n" rel="next">Floating point implementation</a>, Previous: <a href="Characters-implementation.html#Characters-implementation" accesskey="p" rel="prev">Characters implementation</a>, Up: <a href="C-Implementation.html#C-Implementation" accesskey="u" rel="up">C Implementation</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Integers"></a>
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<h3 class="section">4.5 Integers</h3>
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<ul>
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<li> <cite>Any extended integer types that exist in the implementation (C99
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and C11 6.2.5).</cite>
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<p>GCC does not support any extended integer types.
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</p>
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</li><li> <cite>Whether signed integer types are represented using sign and magnitude,
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two’s complement, or one’s complement, and whether the extraordinary value
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is a trap representation or an ordinary value (C99 and C11 6.2.6.2).</cite>
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<p>GCC supports only two’s complement integer types, and all bit patterns
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are ordinary values.
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</p>
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</li><li> <cite>The rank of any extended integer type relative to another extended
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integer type with the same precision (C99 and C11 6.3.1.1).</cite>
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<p>GCC does not support any extended integer types.
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</p>
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</li><li> <cite>The result of, or the signal raised by, converting an integer to a
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signed integer type when the value cannot be represented in an object of
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that type (C90 6.2.1.2, C99 and C11 6.3.1.3).</cite>
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<p>For conversion to a type of width <em>N</em>, the value is reduced
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modulo <em>2^N</em> to be within range of the type; no signal is raised.
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</p>
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</li><li> <cite>The results of some bitwise operations on signed integers (C90
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6.3, C99 and C11 6.5).</cite>
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<p>Bitwise operators act on the representation of the value including
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both the sign and value bits, where the sign bit is considered
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immediately above the highest-value value bit. Signed ‘<samp>>></samp>’ acts
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on negative numbers by sign extension.
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</p>
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<p>As an extension to the C language, GCC does not use the latitude given in
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C99 and C11 only to treat certain aspects of signed ‘<samp><<</samp>’ as undefined.
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However, <samp>-fsanitize=shift</samp> (and <samp>-fsanitize=undefined</samp>) will
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diagnose such cases. They are also diagnosed where constant
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expressions are required.
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</p>
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</li><li> <cite>The sign of the remainder on integer division (C90 6.3.5).</cite>
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<p>GCC always follows the C99 and C11 requirement that the result of division is
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truncated towards zero.
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</p>
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</li></ul>
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<hr>
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<div class="header">
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<p>
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Next: <a href="Floating-point-implementation.html#Floating-point-implementation" accesskey="n" rel="next">Floating point implementation</a>, Previous: <a href="Characters-implementation.html#Characters-implementation" accesskey="p" rel="prev">Characters implementation</a>, Up: <a href="C-Implementation.html#C-Implementation" accesskey="u" rel="up">C Implementation</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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</body>
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</html>
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