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Next: <a rel="next" accesskey="n" href="s390-Mnemonics.html#s390-Mnemonics">s390 Mnemonics</a>,
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<h5 class="subsubsection">9.38.3.1 Register naming</h5>
<p><a name="index-register-naming_002c-s390-1891"></a><a name="index-s390-register-naming-1892"></a>
The <code>as</code> recognizes a number of predefined symbols for the
various processor registers. A register specification in one of the
instruction formats is an unsigned integer between 0 and 15. The specific
instruction and the position of the register in the instruction format
denotes the type of the register. The register symbols are prefixed with
‘<samp><span class="samp">%</span></samp>’:
<pre class="display">
<p><table summary=""><tr align="left"><td valign="top">%rN </td><td valign="top">the 16 general purpose registers, 0 <= N <= 15
<br></td></tr><tr align="left"><td valign="top">%fN </td><td valign="top">the 16 floating point registers, 0 <= N <= 15
<br></td></tr><tr align="left"><td valign="top">%aN </td><td valign="top">the 16 access registers, 0 <= N <= 15
<br></td></tr><tr align="left"><td valign="top">%cN </td><td valign="top">the 16 control registers, 0 <= N <= 15
<br></td></tr><tr align="left"><td valign="top">%lit </td><td valign="top">an alias for the general purpose register %r13
<br></td></tr><tr align="left"><td valign="top">%sp </td><td valign="top">an alias for the general purpose register %r15
<br></td></tr></table>
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