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<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>fma - OpenGL Shading Language (GLSL)</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="fma"></a><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"><p><code class="funcdef">genType <b class="fsfunc">fma</b>(</code>genType <var class="pdparam">a</var>, genType <var class="pdparam">b</var>, genType <var class="pdparam">c</var><code>)</code>;</p><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">genDType <b class="fsfunc">fma</b>(</code></td><td>genDType  </td><td><var class="pdparam">a</var>, </td></tr><tr><td> </td><td>genDType  </td><td><var class="pdparam">b</var>, </td></tr><tr><td> </td><td>genDType  </td><td><var class="pdparam">c</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><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" lang="en" xml:lang="en"><a id="description"></a><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 type="disc"><li><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.</li><li>The precision of <code class="function">fma</code>() can differ from the precision
                of the expression <code class="code">a * b + c</code>.</li><li><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>.</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><div class="refsect1" lang="en" xml:lang="en"><a id="versions"></a><h2>Version Support</h2><div class="informaltable"><table border="1"><colgroup><col align="left" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /></colgroup><thead><tr><th align="left"><span class="bold"><strong>Function</strong></span></th><th align="left"><span class="bold"><strong>Version 1.10</strong></span></th><th align="left"><span class="bold"><strong>Version 1.20</strong></span></th><th align="left"><span class="bold"><strong>Version 1.30</strong></span></th><th align="left"><span class="bold"><strong>Version 1.40</strong></span></th><th align="left"><span class="bold"><strong>Version 1.50</strong></span></th><th align="left"><span class="bold"><strong>Version 3.30</strong></span></th><th align="left"><span class="bold"><strong>Version 4.00</strong></span></th><th align="left"><span class="bold"><strong>Version 4.10</strong></span></th><th align="left"><span class="bold"><strong>Version 4.20</strong></span></th><th align="center"><span class="bold"><strong>Version 4.30</strong></span></th></tr><tr><th align="left">fma (genType)</th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th></tr><tr><th align="left">fma (genDType)</th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th></tr></thead></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2011 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 href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p></div></div></body></html>
