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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>bitfieldExtract - 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="bitfieldExtract"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>bitfieldExtract — extract a range of bits from an integer</p></div><div class="refsynopsisdiv"><h2>Declaration</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">genIType <b class="fsfunc">bitfieldExtract</b>(</code></td><td>genIType  </td><td><var class="pdparam">value</var>, </td></tr><tr><td> </td><td>int  </td><td><var class="pdparam">offset</var>, </td></tr><tr><td> </td><td>int  </td><td><var class="pdparam">bits</var><code>)</code>;</td></tr></table><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">genUType <b class="fsfunc">bitfieldExtract</b>(</code></td><td>genUType  </td><td><var class="pdparam">value</var>, </td></tr><tr><td> </td><td>int  </td><td><var class="pdparam">offset</var>, </td></tr><tr><td> </td><td>int  </td><td><var class="pdparam">bits</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>value</code></em></span></dt><dd><p>
                    Specifies the integer from which to extract bits.
                </p></dd><dt><span class="term"><em class="parameter"><code>offset</code></em></span></dt><dd><p>
                    Specifies the index of the first bit to extract.
                </p></dd><dt><span class="term"><em class="parameter"><code>bits</code></em></span></dt><dd><p>
                    Specifies the number of bits to extract.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">bitfieldExtract</code> extracts a subset of the bits of <em class="parameter"><code>value</code></em> and returns
            it in the least significant bits of the result. The range of bits extracted is [<em class="parameter"><code>offset</code></em>, <em class="parameter"><code>offset</code></em> + <em class="parameter"><code>bits</code></em> + 1].
        </p><p>
            For unsigned data types, the most significant bits of the result will be set to zero. For signed data types, the most significant bits will be set to the value of
            bit <em class="parameter"><code>offset</code></em> + <em class="parameter"><code>base</code></em> - 1 (i.e., it is <span class="emphasis"><em>sign extended</em></span> to the width of the return type).
        </p><p>
        </p><p>
            If <em class="parameter"><code>bits</code></em> is zero, the result will be zero. The result will be undefined if <em class="parameter"><code>offset</code></em> or <em class="parameter"><code>bits</code></em> is negative,
            or if the sum of <em class="parameter"><code>offset</code></em> and <em class="parameter"><code>bits</code></em> is greater than the number of bits used to store the operand.
        </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">bitfieldInsert</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="seealso"></a><h2>See Also</h2><p>
            <a href="bitfieldExtract.xml"><span class="citerefentry"><span class="refentrytitle">bitfieldExtract</span></span></a>
        </p></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>
