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    <title>hadd, rhadd</title>
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    <div class="refentry">
      <a id="id-1"></a>
      <div class="titlepage"></div>
      <div xmlns="" class="refnamediv">
        <a xmlns="http://www.w3.org/1999/xhtml" id="hadd"></a>
        <h1>hadd, rhadd</h1>
        <p>
            Returns (<code xmlns="http://www.w3.org/1999/xhtml" class="varname">x</code> + <code xmlns="http://www.w3.org/1999/xhtml" class="varname">y</code>) &gt;&gt; 1, or (<code xmlns="http://www.w3.org/1999/xhtml" class="varname">x</code> + <code xmlns="http://www.w3.org/1999/xhtml" class="varname">y</code> + 1) &gt;&gt; 1
        </p>
      </div>
      <div class="refsynopsisdiv">
        <h2></h2>
        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
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              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    gentype
                    <strong class="fsfunc">                   
                        hadd
                    </strong>
                (</code>
                <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">x</var>, </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">y</var><code>)</code></td>
            </tr>
          </table>
        </div>
        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
            <tr valign="bottom">
              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    gentype
                    <strong class="fsfunc">                   
                        rhadd
                    </strong>
                (</code>
                <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">x</var>, </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>gentype <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">y</var><code>)</code></td>
            </tr>
          </table>
        </div>
      </div>
      <div class="refsect1">
        <a id="description"></a>
        <h2>Description</h2>
        <p>
            <code class="function">hadd</code> returns (<code class="varname">x</code>+<code class="varname">y</code>) &gt;&gt; 1. The intermediate sum does not modulo overflow.
        </p>
        <p>
            <code class="function">rhadd</code> returns (<code class="varname">x</code>+<code class="varname">y</code>+1) &gt;&gt; 1. The intermediate sum does not modulo overflow. 
        </p>
      </div>
      <div class="refsect1">
        <a id="notes"></a>
        <h2>Notes</h2>
        <p>
        Frequently vector operations need n + 1 bits temporarily to calculate a result. The <code class="function">rhadd</code> instruction gives you an extra bit without needing to upsample and downsample. This can be a profound performance win.
        </p>
        <p>
            Built-in integer functions can be used to take scalar or vector arguments. The
            vector versions of the integer functions operate component-wise. The description 
            is per component. 
        </p>
        <p>
            We use the generic type name <span class="type">gentype</span> to indicate 
            that the function can take <span class="type">char</span>, <span class="type">char{2|3|4|8|16}</span>, 
            <span class="type">uchar</span>, <span class="type">uchar{2|3|4|8|16}</span>, <span class="type">short</span>, 
            <span class="type">short{2|3|4|8|16}</span>, <span class="type">ushort</span>, <span class="type">ushort{2|3|4|8|16}</span>, 
            <span class="type">int</span>, <span class="type">int{2|3|4|8|16}</span>, <span class="type">uint</span>, 
            <span class="type">uint{2|3|4|8|16}</span>, <span class="type">long</span>, <span class="type">long{2|3|4|8|16}</span>, 
            <span class="type">ulong</span>, or <span class="type">ulong{2|3|4|8|16}</span> as the type for the arguments. 
            We use the generic type name <span class="type">ugentype</span> to refer to unsigned versions of 
            <span class="type">gentype</span>. For example, if <span class="type">gentype</span> is <span class="type">char4</span>, 
            <span class="type">ugentype</span> is <span class="type">uchar4</span>. 
        </p>
        <p>          
            We also use the generic type name <span class="type">sgentype</span> to indicate that the 
            function can take a scalar data type i.e. <span class="type">char</span>, <span class="type">uchar</span>, 
            <span class="type">short</span>, <span class="type">ushort</span>, <span class="type">int</span>, <span class="type">uint</span>,
            <span class="type">long</span>, or <span class="type">ulong</span> as the type for the arguments. 
            For built-in integer functions that take <span class="type">gentype</span> and 
            <span class="type">sgentype</span> arguments, the <span class="type">gentype</span> argument must be a 
            vector or scalar version of the <span class="type">sgentype</span> argument. For example, if
            <span class="type">sgentype</span> is <span class="type">uchar</span>, <span class="type">gentype</span> must be
            <span class="type">uchar</span> or <span class="type">uchar{2|3|4|8|16}</span>.
        </p>
        <p>
            For any specific use of a function, the actual type has to be the same for 
            all arguments and the return type unless otherwise specified.
        </p>
      </div>
      <div class="refsect1">
        <a id="specification"></a>
        <h2>Specification</h2>
        <p>
            <img src="pdficon_small1.gif" />
                                                 
            <a href="http://www.khronos.org/registry/cl/specs/opencl-1.1.pdf#page=211" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div class="refsect1">
        <a id="seealso"></a>
        <h2>Also see</h2>
        <p>
            <a class="citerefentry" href="integerFunctions.html"><span class="citerefentry"><span class="refentrytitle">Integer Functions</span></span></a> 
        </p>
      </div>
      <div xmlns="" class="refsect3" lang="en" xml:lang="en"><a xmlns="http://www.w3.org/1999/xhtml" id="Copyright"></a><h4 xmlns="http://www.w3.org/1999/xhtml"></h4><img xmlns="http://www.w3.org/1999/xhtml" src="KhronosLogo.jpg" /><p xmlns="http://www.w3.org/1999/xhtml"></p>Copyright © 2007-2010 The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
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in all copies or substantial portions of the Materials.
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