<div class="refentry" id="fma">

<div class="titlepage"></div>

<div class="refnamediv">

<h2>Name</h2>

<p>fma — perform a fused multiply-add operation</p>

</div>

<div class="refsynopsisdiv">

<h2>Declaration</h2>

<div class="funcsynopsis">

<table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">

<tr>

<td>

<code class="funcdef">genType <strong class="fsfunc">fma</strong>(</code>

</td>

<td>genType <var class="pdparam">a</var>, </td>

</tr>

<tr>

<td> </td>

<td>genType <var class="pdparam">b</var>, </td>

</tr>

<tr>

<td> </td>

<td>genType <var class="pdparam">c</var><code>)</code>;</td>

</tr>

</table>

<div class="funcprototype-spacer"> </div>

</div>

</div>

<div class="refsect1" id="parameters">

<h2>Parameters</h2>

<div class="variablelist">

<dl class="variablelist">

<dt>

<span class="term">

<em class="parameter">

<code>a</code>

</em>

</span>

</dt>

<dd>

<p>

Specifies the first multiplicand.

</p>

</dd>

<dt>

<span class="term">

<em class="parameter">

<code>b</code>

</em>

</span>

</dt>

<dd>

<p>

Specifies the second multiplicand.

</p>

</dd>

<dt>

<span class="term">

<em class="parameter">

<code>c</code>

</em>

</span>

</dt>

<dd>

<p>

Specifies the value to be added to the result.

</p>

</dd>

</dl>

</div>

</div>

<div class="refsect1" id="description">

<h2>Description</h2>

<p>

<code class="function">fma</code> performs, where possible, a fused multiply-add operation,

returning <code class="code">a * b + c</code>.

In use cases where the return value is eventually consumed by a variable declared as

<code class="code">precise</code>:

</p>

<div class="itemizedlist">

<ul class="itemizedlist" style="list-style-type: disc; ">

<li class="listitem">

<p>

<code class="function">fma</code>() is considered a single

operation, whereas the expression <code class="code">a * b +

c</code> consumed by a variable declared as

<code class="code">precise</code> is considered two operations.

</p>

</li>

<li class="listitem">

<p>

The precision of <code class="function">fma</code>() can

differ from the precision of the expression <code class="code">a

* b + c</code>.

</p>

</li>

<li class="listitem">

<p>

<code class="function">fma</code>() will be computed with the

same precision as any other

<code class="function">fma</code>() consumed by a

<code class="code">precise</code> variable, giving invariant

results for the same input values of

<em class="parameter"><code>a</code></em>, <em class="parameter"><code>b</code></em>

and <em class="parameter"><code>c</code></em>.

</p>

</li>

</ul>

</div>

<p>

Otherwise, in the absense of <code class="code">precise</code> consumption, there are no

special constraints on the number of operations or difference in precision between

<code class="function">fma</code>() and the expression <code class="code">a * b + c</code>.

</p>

</div>

{$pipelinestall}{$examples}

<div class="refsect1" id="versions">

<h2>Version Support</h2>

<div class="informaltable">

<table style="border-collapse: collapse; border-top: 2px solid ; border-bottom: 2px solid ; border-left: 2px solid ; border-right: 2px solid ; ">

<colgroup>

<col style="text-align: left; "/>

<col style="text-align: center; " class="firstvers"/>

<col style="text-align: center; "/>

<col style="text-align: center; " class="lastvers"/>

</colgroup>

<thead>

<tr>

<th style="text-align: left; border-right: 2px solid ; ">

</th>

<th style="text-align: center; border-bottom: 2px solid ; " colspan="3">

<span class="bold"><strong>OpenGL ES Shading Language Version</strong></span>

</th>

</tr>

<tr>

<th style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">

<span class="bold"><strong>Function Name</strong></span>

</th>

<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">

<span class="bold"><strong>1.00</strong></span>

</th>

<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">

<span class="bold"><strong>3.00</strong></span>

</th>

<th style="text-align: center; border-bottom: 2px solid ; ">

<span class="bold"><strong>3.10</strong></span>

</th>

</tr>

</thead>

<tbody>

<tr>

<td style="text-align: left; border-right: 2px solid ; ">

<code class="function">fma</code>

</td>

<td style="text-align: center; border-right: 2px solid ; ">-</td>

<td style="text-align: center; border-right: 2px solid ; ">-</td>

<td style="text-align: center; ">✔</td>

</tr>

</tbody>

</table>

</div>

</div>

<div class="refsect1" id="Copyright">

<h2>Copyright</h2>

<p>

Copyright © 2011-2014 Khronos Group.

This material may be distributed subject to the terms and conditions set forth in

the Open Publication License, v 1.0, 8 June 1999.

<a class="link" href="https://opencontent.org/openpub/" target="_top">https://opencontent.org/openpub/</a>.

</p>

</div>

</div>