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| <h5 class="subsubsection">9.41.3.1 Register naming</h5> |
| |
| <p><a name="index-register-naming_002c-s390-2068"></a><a name="index-s390-register-naming-2069"></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 |
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