113 lines
5.0 KiB
HTML
113 lines
5.0 KiB
HTML
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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) 1988-2016 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 5.2, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>GNU Compiler Collection (GCC) Internals: Mode Iterators</title>
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<meta name="description" content="GNU Compiler Collection (GCC) Internals: Mode Iterators">
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<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Mode Iterators">
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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="Iterators.html#Iterators" rel="up" title="Iterators">
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<link href="Defining-Mode-Iterators.html#Defining-Mode-Iterators" rel="next" title="Defining Mode Iterators">
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<link href="Iterators.html#Iterators" rel="prev" title="Iterators">
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<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
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<a name="Mode-Iterators"></a>
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<div class="header">
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<p>
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Next: <a href="Code-Iterators.html#Code-Iterators" accesskey="n" rel="next">Code Iterators</a>, Up: <a href="Iterators.html#Iterators" accesskey="u" rel="up">Iterators</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="Mode-Iterators-1"></a>
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<h4 class="subsection">16.23.1 Mode Iterators</h4>
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<a name="index-mode-iterators-in-_002emd-files"></a>
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<p>Ports often need to define similar patterns for two or more different modes.
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For example:
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</p>
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<ul>
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<li> If a processor has hardware support for both single and double
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floating-point arithmetic, the <code>SFmode</code> patterns tend to be
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very similar to the <code>DFmode</code> ones.
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</li><li> If a port uses <code>SImode</code> pointers in one configuration and
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<code>DImode</code> pointers in another, it will usually have very similar
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<code>SImode</code> and <code>DImode</code> patterns for manipulating pointers.
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</li></ul>
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<p>Mode iterators allow several patterns to be instantiated from one
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<samp>.md</samp> file template. They can be used with any type of
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rtx-based construct, such as a <code>define_insn</code>,
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<code>define_split</code>, or <code>define_peephole2</code>.
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</p>
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<table class="menu" border="0" cellspacing="0">
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<tr><td align="left" valign="top">• <a href="Defining-Mode-Iterators.html#Defining-Mode-Iterators" accesskey="1">Defining Mode Iterators</a>:</td><td> </td><td align="left" valign="top">Defining a new mode iterator.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Substitutions.html#Substitutions" accesskey="2">Substitutions</a>:</td><td> </td><td align="left" valign="top">Combining mode iterators with substitutions
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Examples.html#Examples" accesskey="3">Examples</a>:</td><td> </td><td align="left" valign="top">Examples
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</td></tr>
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</table>
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</body>
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</html>
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