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Next: <a href="Conditional-Execution.html#Conditional-Execution" accesskey="n" rel="next">Conditional Execution</a>, Previous: <a href="Peephole-Definitions.html#Peephole-Definitions" accesskey="p" rel="prev">Peephole Definitions</a>, Up: <a href="Machine-Desc.html#Machine-Desc" accesskey="u" rel="up">Machine Desc</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="Instruction-Attributes"></a>
<h3 class="section">16.19 Instruction Attributes</h3>
<a name="index-insn-attributes"></a>
<a name="index-instruction-attributes"></a>

<p>In addition to describing the instruction supported by the target machine,
the <samp>md</samp> file also defines a group of <em>attributes</em> and a set of
values for each.  Every generated insn is assigned a value for each attribute.
One possible attribute would be the effect that the insn has on the machine&rsquo;s
condition code.  This attribute can then be used by <code>NOTICE_UPDATE_CC</code>
to track the condition codes.
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<tr><td align="left" valign="top">&bull; <a href="Defining-Attributes.html#Defining-Attributes" accesskey="1">Defining Attributes</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Specifying attributes and their values.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Expressions.html#Expressions" accesskey="2">Expressions</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Valid expressions for attribute values.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Tagging-Insns.html#Tagging-Insns" accesskey="3">Tagging Insns</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Assigning attribute values to insns.
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<tr><td align="left" valign="top">&bull; <a href="Attr-Example.html#Attr-Example" accesskey="4">Attr Example</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">An example of assigning attributes.
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<tr><td align="left" valign="top">&bull; <a href="Insn-Lengths.html#Insn-Lengths" accesskey="5">Insn Lengths</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Computing the length of insns.
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<tr><td align="left" valign="top">&bull; <a href="Constant-Attributes.html#Constant-Attributes" accesskey="6">Constant Attributes</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Defining attributes that are constant.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Mnemonic-Attribute.html#Mnemonic-Attribute" accesskey="7">Mnemonic Attribute</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Obtain the instruction mnemonic as attribute value.
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<tr><td align="left" valign="top">&bull; <a href="Delay-Slots.html#Delay-Slots" accesskey="8">Delay Slots</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Defining delay slots required for a machine.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Processor-pipeline-description.html#Processor-pipeline-description" accesskey="9">Processor pipeline description</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Specifying information for insn scheduling.
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