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<title>Using the GNU Compiler Collection (GCC): ARC Function Attributes</title>

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<a name="ARC-Function-Attributes"></a>
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Next: <a href="ARM-Function-Attributes.html#ARM-Function-Attributes" accesskey="n" rel="next">ARM Function Attributes</a>, Previous: <a href="AArch64-Function-Attributes.html#AArch64-Function-Attributes" accesskey="p" rel="prev">AArch64 Function Attributes</a>, Up: <a href="Function-Attributes.html#Function-Attributes" accesskey="u" rel="up">Function Attributes</a> &nbsp; [<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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<a name="ARC-Function-Attributes-1"></a>
<h4 class="subsection">6.31.3 ARC Function Attributes</h4>

<p>These function attributes are supported by the ARC back end:
</p>
<dl compact="compact">
<dt><code>interrupt</code></dt>
<dd><a name="index-interrupt-function-attribute_002c-ARC"></a>
<p>Use this attribute to indicate
that the specified function is an interrupt handler.  The compiler generates
function entry and exit sequences suitable for use in an interrupt handler
when this attribute is present.
</p>
<p>On the ARC, you must specify the kind of interrupt to be handled
in a parameter to the interrupt attribute like this:
</p>
<div class="smallexample">
<pre class="smallexample">void f () __attribute__ ((interrupt (&quot;ilink1&quot;)));
</pre></div>

<p>Permissible values for this parameter are: <code>ilink1</code><!-- /@w --> and
<code>ilink2</code><!-- /@w -->.
</p>
</dd>
<dt><code>long_call</code></dt>
<dt><code>medium_call</code></dt>
<dt><code>short_call</code></dt>
<dd><a name="index-long_005fcall-function-attribute_002c-ARC"></a>
<a name="index-medium_005fcall-function-attribute_002c-ARC"></a>
<a name="index-short_005fcall-function-attribute_002c-ARC"></a>
<a name="index-indirect-calls_002c-ARC"></a>
<p>These attributes specify how a particular function is called.
These attributes override the
<samp>-mlong-calls</samp> and <samp>-mmedium-calls</samp> (see <a href="ARC-Options.html#ARC-Options">ARC Options</a>)
command-line switches and <code>#pragma long_calls</code> settings.
</p>
<p>For ARC, a function marked with the <code>long_call</code> attribute is
always called using register-indirect jump-and-link instructions,
thereby enabling the called function to be placed anywhere within the
32-bit address space.  A function marked with the <code>medium_call</code>
attribute will always be close enough to be called with an unconditional
branch-and-link instruction, which has a 25-bit offset from
the call site.  A function marked with the <code>short_call</code>
attribute will always be close enough to be called with a conditional
branch-and-link instruction, which has a 21-bit offset from
the call site.
</p></dd>
</dl>


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