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<title>Using as: Xtensa Directives</title>
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<a name="Xtensa-Directives"></a>
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<div class="header">
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<p>
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Previous: <a href="Xtensa-Relaxation.html#Xtensa-Relaxation" accesskey="p" rel="previous">Xtensa Relaxation</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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<hr>
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<a name="Directives-3"></a>
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<h4 class="subsection">9.55.5 Directives</h4>
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<a name="index-Xtensa-directives"></a>
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<a name="index-directives_002c-Xtensa"></a>
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<p>The Xtensa assembler supports a region-based directive syntax:
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</p>
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<div class="smallexample">
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<pre class="smallexample"> .begin <var>directive</var> [<var>options</var>]
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…
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.end <var>directive</var>
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</pre></div>
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<p>All the Xtensa-specific directives that apply to a region of code use
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this syntax.
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</p>
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<p>The directive applies to code between the <code>.begin</code> and the
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<code>.end</code>. The state of the option after the <code>.end</code> reverts to
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what it was before the <code>.begin</code>.
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A nested <code>.begin</code>/<code>.end</code> region can further
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change the state of the directive without having to be aware of its
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outer state. For example, consider:
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</p>
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<div class="smallexample">
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<pre class="smallexample"> .begin no-transform
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L: add a0, a1, a2
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</pre><pre class="smallexample"> .begin transform
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M: add a0, a1, a2
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.end transform
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</pre><pre class="smallexample">N: add a0, a1, a2
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.end no-transform
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</pre></div>
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<p>The <code>ADD</code> opcodes at <code>L</code> and <code>N</code> in the outer
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<code>no-transform</code> region both result in <code>ADD</code> machine instructions,
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but the assembler selects an <code>ADD.N</code> instruction for the
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<code>ADD</code> at <code>M</code> in the inner <code>transform</code> region.
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</p>
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<p>The advantage of this style is that it works well inside macros which can
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preserve the context of their callers.
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</p>
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<p>The following directives are available:
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</p><table class="menu" border="0" cellspacing="0">
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<tr><td align="left" valign="top">• <a href="Schedule-Directive.html#Schedule-Directive" accesskey="1">Schedule Directive</a>:</td><td> </td><td align="left" valign="top">Enable instruction scheduling.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Longcalls-Directive.html#Longcalls-Directive" accesskey="2">Longcalls Directive</a>:</td><td> </td><td align="left" valign="top">Use Indirect Calls for Greater Range.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Transform-Directive.html#Transform-Directive" accesskey="3">Transform Directive</a>:</td><td> </td><td align="left" valign="top">Disable All Assembler Transformations.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Literal-Directive.html#Literal-Directive" accesskey="4">Literal Directive</a>:</td><td> </td><td align="left" valign="top">Intermix Literals with Instructions.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Literal-Position-Directive.html#Literal-Position-Directive" accesskey="5">Literal Position Directive</a>:</td><td> </td><td align="left" valign="top">Specify Inline Literal Pool Locations.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Literal-Prefix-Directive.html#Literal-Prefix-Directive" accesskey="6">Literal Prefix Directive</a>:</td><td> </td><td align="left" valign="top">Specify Literal Section Name Prefix.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Absolute-Literals-Directive.html#Absolute-Literals-Directive" accesskey="7">Absolute Literals Directive</a>:</td><td> </td><td align="left" valign="top">Control PC-Relative vs. Absolute Literals.
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</td></tr>
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</table>
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<hr>
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<div class="header">
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<p>
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Previous: <a href="Xtensa-Relaxation.html#Xtensa-Relaxation" accesskey="p" rel="previous">Xtensa Relaxation</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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