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

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<a name="RX-Function-Attributes"></a>
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<p>
Next: <a href="S_002f390-Function-Attributes.html#S_002f390-Function-Attributes" accesskey="n" rel="next">S/390 Function Attributes</a>, Previous: <a href="RL78-Function-Attributes.html#RL78-Function-Attributes" accesskey="p" rel="prev">RL78 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>
</div>
<hr>
<a name="RX-Function-Attributes-1"></a>
<h4 class="subsection">6.31.25 RX Function Attributes</h4>

<p>These function attributes are supported by the RX back end:
</p>
<dl compact="compact">
<dt><code>fast_interrupt</code></dt>
<dd><a name="index-fast_005finterrupt-function-attribute_002c-RX"></a>
<p>Use this attribute on the RX port to indicate that the specified
function is a fast interrupt handler.  This is just like the
<code>interrupt</code> attribute, except that <code>freit</code> is used to return
instead of <code>reit</code>.
</p>
</dd>
<dt><code>interrupt</code></dt>
<dd><a name="index-interrupt-function-attribute_002c-RX"></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 RX targets, you may specify one or more vector numbers as arguments
to the attribute, as well as naming an alternate table name.
Parameters are handled sequentially, so one handler can be assigned to
multiple entries in multiple tables.  One may also pass the magic
string <code>&quot;$default&quot;</code> which causes the function to be used for any
unfilled slots in the current table.
</p>
<p>This example shows a simple assignment of a function to one vector in
the default table (note that preprocessor macros may be used for
chip-specific symbolic vector names):
</p><div class="smallexample">
<pre class="smallexample">void __attribute__ ((interrupt (5))) txd1_handler ();
</pre></div>

<p>This example assigns a function to two slots in the default table
(using preprocessor macros defined elsewhere) and makes it the default
for the <code>dct</code> table:
</p><div class="smallexample">
<pre class="smallexample">void __attribute__ ((interrupt (RXD1_VECT,RXD2_VECT,&quot;dct&quot;,&quot;$default&quot;)))
	txd1_handler ();
</pre></div>

</dd>
<dt><code>naked</code></dt>
<dd><a name="index-naked-function-attribute_002c-RX"></a>
<p>This attribute allows the compiler to construct the
requisite function declaration, while allowing the body of the
function to be assembly code. The specified function will not have
prologue/epilogue sequences generated by the compiler. Only basic
<code>asm</code> statements can safely be included in naked functions
(see <a href="Basic-Asm.html#Basic-Asm">Basic Asm</a>). While using extended <code>asm</code> or a mixture of
basic <code>asm</code> and C code may appear to work, they cannot be
depended upon to work reliably and are not supported.
</p>
</dd>
<dt><code>vector</code></dt>
<dd><a name="index-vector-function-attribute_002c-RX"></a>
<p>This RX attribute is similar to the <code>interrupt</code> attribute, including its
parameters, but does not make the function an interrupt-handler type
function (i.e. it retains the normal C function calling ABI).  See the
<code>interrupt</code> attribute for a description of its arguments.
</p></dd>
</dl>

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Next: <a href="S_002f390-Function-Attributes.html#S_002f390-Function-Attributes" accesskey="n" rel="next">S/390 Function Attributes</a>, Previous: <a href="RL78-Function-Attributes.html#RL78-Function-Attributes" accesskey="p" rel="prev">RL78 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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