103 lines
4.5 KiB
HTML
103 lines
4.5 KiB
HTML
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<title>Using as: OpenRISC-Regs</title>
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<a name="OpenRISC_002dRegs"></a>
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Next: <a href="OpenRISC_002dRelocs.html#OpenRISC_002dRelocs" accesskey="n" rel="next">OpenRISC-Relocs</a>, Previous: <a href="OpenRISC_002dChars.html#OpenRISC_002dChars" accesskey="p" rel="previous">OpenRISC-Chars</a>, Up: <a href="OpenRISC_002dSyntax.html#OpenRISC_002dSyntax" accesskey="u" rel="up">OpenRISC-Syntax</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Register-Names-14"></a>
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<h4 class="subsubsection">9.33.1.2 Register Names</h4>
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<a name="index-OpenRISC-registers"></a>
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<a name="index-register-names_002c-OpenRISC"></a>
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<p>The OpenRISC register file contains 32 general pupose registers.
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</p>
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<ul>
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<li> The 32 general purpose registers are referred to as ‘<samp>r<var>n</var></samp>’.
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</li><li> The stack pointer register ‘<samp>r1</samp>’ can be referenced using the alias
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‘<samp>sp</samp>’.
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</li><li> The frame pointer register ‘<samp>r2</samp>’ can be referenced using the alias
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‘<samp>fp</samp>’.
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</li><li> The link register ‘<samp>r9</samp>’ can be referenced using the alias ‘<samp>lr</samp>’.
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</li></ul>
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<p>Floating point operations use the same general purpose registers. The
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instructions <code>lf.itof.s</code> (single precision) and <code>lf.itof.d</code> (double
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precision) can be used to convert integer values to floating point.
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Likewise, instructions <code>lf.ftoi.s</code> (single precision) and
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<code>lf.ftoi.d</code> (double precision) can be used to convert floating point to
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integer.
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</p>
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<p>OpenRISC also contains privileged special purpose registers (SPRs). The
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SPRs are accessed using the <code>l.mfspr</code> and <code>l.mtspr</code> instructions.
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</p>
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