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<title>Using as: MIPS FP ABI Variants</title>

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<a name="MIPS-FP-ABI-Variants"></a>
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<p>
Next: <a href="MIPS-FP-ABI-Selection.html#MIPS-FP-ABI-Selection" accesskey="n" rel="next">MIPS FP ABI Selection</a>, Previous: <a href="MIPS-FP-ABI-History.html#MIPS-FP-ABI-History" accesskey="p" rel="prev">MIPS FP ABI History</a>, Up: <a href="MIPS-FP-ABIs.html#MIPS-FP-ABIs" accesskey="u" rel="up">MIPS FP ABIs</a> &nbsp; [<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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<hr>
<a name="Supported-FP-ABIs"></a>
<h4 class="subsubsection">9.27.9.2 Supported FP ABIs</h4>
<p>The supported floating-point ABI variants are:
</p>
<dl compact="compact">
<dt><code>0 - No floating-point</code></dt>
<dd><p>This variant is used to indicate that floating-point is not used within
the module at all and therefore has no impact on the ABI.  This is the
default.
</p>
</dd>
<dt><code>1 - Double-precision</code></dt>
<dd><p>This variant indicates that double-precision support is used.  For 64-bit
ABIs this means that 64-bit wide floating-point registers are required.
For 32-bit ABIs this means that 32-bit wide floating-point registers are
required and double-precision operations use pairs of registers.
</p>
</dd>
<dt><code>2 - Single-precision</code></dt>
<dd><p>This variant indicates that single-precision support is used.  Double
precision operations will be supported via soft-float routines.
</p>
</dd>
<dt><code>3 - Soft-float</code></dt>
<dd><p>This variant indicates that although floating-point support is used all
operations are emulated in software.  This means the ABI is modified to
pass all floating-point data in general-purpose registers.
</p>
</dd>
<dt><code>4 - Deprecated</code></dt>
<dd><p>This variant existed as an initial attempt at supporting 64-bit wide
floating-point registers for O32 ABI on a MIPS32r2 CPU.  This has been
superseded by 5, 6 and 7.
</p>
</dd>
<dt><code>5 - Double-precision 32-bit CPU, 32-bit or 64-bit FPU</code></dt>
<dd><p>This variant is used by 32-bit ABIs to indicate that the floating-point
code in the module has been designed to operate correctly with either
32-bit wide or 64-bit wide floating-point registers.  Double-precision
support is used.  Only O32 currently supports this variant and requires
a minimum architecture of MIPS II.
</p>
</dd>
<dt><code>6 - Double-precision 32-bit FPU, 64-bit FPU</code></dt>
<dd><p>This variant is used by 32-bit ABIs to indicate that the floating-point
code in the module requires 64-bit wide floating-point registers.
Double-precision support is used.  Only O32 currently supports this
variant and requires a minimum architecture of MIPS32r2.
</p>
</dd>
<dt><code>7 - Double-precision compat 32-bit FPU, 64-bit FPU</code></dt>
<dd><p>This variant is used by 32-bit ABIs to indicate that the floating-point
code in the module requires 64-bit wide floating-point registers.
Double-precision support is used.  This differs from the previous ABI
as it restricts use of odd-numbered single-precision registers.  Only
O32 currently supports this variant and requires a minimum architecture
of MIPS32r2.
</p></dd>
</dl>

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Next: <a href="MIPS-FP-ABI-Selection.html#MIPS-FP-ABI-Selection" accesskey="n" rel="next">MIPS FP ABI Selection</a>, Previous: <a href="MIPS-FP-ABI-History.html#MIPS-FP-ABI-History" accesskey="p" rel="prev">MIPS FP ABI History</a>, Up: <a href="MIPS-FP-ABIs.html#MIPS-FP-ABIs" accesskey="u" rel="up">MIPS FP ABIs</a> &nbsp; [<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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