113 lines
5.0 KiB
HTML
113 lines
5.0 KiB
HTML
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<head>
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<title>GNU Compiler Collection (GCC) Internals: Mode Iterators</title>
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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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<a name="Mode-Iterators"></a>
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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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<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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