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98 lines
4.8 KiB
HTML
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<!-- This file documents the GNU Assembler "as".
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Copyright (C) 1991-2019 Free Software Foundation, Inc.
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<head>
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<title>Xtensa Relaxation (Using as)</title>
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<link href="AS-Index.html#AS-Index" rel="index" title="AS Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Xtensa-Branch-Relaxation.html#Xtensa-Branch-Relaxation" rel="next" title="Xtensa Branch Relaxation">
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<a name="Xtensa-Relaxation"></a>
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<div class="header">
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<p>
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Next: <a href="Xtensa-Directives.html#Xtensa-Directives" accesskey="n" rel="next">Xtensa Directives</a>, Previous: <a href="Xtensa-Optimizations.html#Xtensa-Optimizations" accesskey="p" rel="prev">Xtensa Optimizations</a>, Up: <a href="Xtensa_002dDependent.html#Xtensa_002dDependent" accesskey="u" rel="up">Xtensa-Dependent</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Xtensa-Relaxation-1"></a>
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<h4 class="subsection">9.54.4 Xtensa Relaxation</h4>
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<a name="index-relaxation"></a>
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<p>When an instruction operand is outside the range allowed for that
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particular instruction field, <code>as</code> can transform the code
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to use a functionally-equivalent instruction or sequence of
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instructions. This process is known as <em>relaxation</em>. This is
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typically done for branch instructions because the distance of the
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branch targets is not known until assembly-time. The Xtensa assembler
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offers branch relaxation and also extends this concept to function
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calls, <code>MOVI</code> instructions and other instructions with immediate
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fields.
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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="Xtensa-Branch-Relaxation.html#Xtensa-Branch-Relaxation" accesskey="1">Xtensa Branch Relaxation</a>:</td><td> </td><td align="left" valign="top">Relaxation of Branches.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Xtensa-Call-Relaxation.html#Xtensa-Call-Relaxation" accesskey="2">Xtensa Call Relaxation</a>:</td><td> </td><td align="left" valign="top">Relaxation of Function Calls.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Xtensa-Jump-Relaxation.html#Xtensa-Jump-Relaxation" accesskey="3">Xtensa Jump Relaxation</a>:</td><td> </td><td align="left" valign="top">Relaxation of Jumps.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Xtensa-Immediate-Relaxation.html#Xtensa-Immediate-Relaxation" accesskey="4">Xtensa Immediate Relaxation</a>:</td><td> </td><td align="left" valign="top">Relaxation of other Immediate Fields.
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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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