upstream-man-pages/manglsl/fma.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3               "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="fma">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2011</year>
   9                 <holder>Khronos Group</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>fma</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>fma</refname>
  17         <refpurpose>perform a fused multiply-add operation</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>Declaration</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>genType <function>fma</function></funcdef>
  23                 <paramdef>genType <parameter>a</parameter></paramdef>
  24                 <paramdef>genType <parameter>b</parameter></paramdef>
  25                 <paramdef>genType <parameter>c</parameter></paramdef>
  26             </funcprototype>
  27             <funcprototype>
  28                 <funcdef>genDType <function>fma</function></funcdef>
  29                 <paramdef>genDType <parameter>a</parameter></paramdef>
  30                 <paramdef>genDType <parameter>b</parameter></paramdef>
  31                 <paramdef>genDType <parameter>c</parameter></paramdef>
  32             </funcprototype>
  33         </funcsynopsis>
  34     </refsynopsisdiv>
  35     <refsect1 id="parameters"><title>Parameters</title>
  36         <variablelist>
  37         <varlistentry>
  38             <term><parameter>a</parameter></term>
  39             <listitem>
  40                 <para>
  41                     Specifies the first multiplicand.
  42                 </para>
  43             </listitem>
  44         </varlistentry>
  45         <varlistentry>
  46             <term><parameter>b</parameter></term>
  47             <listitem>
  48                 <para>
  49                     Specifies the second multiplicand.
  50                 </para>
  51             </listitem>
  52         </varlistentry>
  53         <varlistentry>
  54             <term><parameter>c</parameter></term>
  55             <listitem>
  56                 <para>
  57                     Specifies the value to be added to the result.
  58                 </para>
  59             </listitem>
  60         </varlistentry>
  61         </variablelist>
  62     </refsect1>
  63     <refsect1 id="description"><title>Description</title>
  64         <para>
  65             <function>fma</function> performs, where possible, a fused multiply-add operation,
  66             returning <code>a * b + c</code>.
  67             In use cases where the return value is eventually consumed by a variable declared as
  68             <code>precise</code>:
  69             <itemizedlist>
  70                 <listitem><function>fma</function>() is considered a single operation, whereas the
  71                 expression <code>a * b + c</code> consumed by a variable declared as <code>precise</code>
  72                 is considered two operations.</listitem>
  73                 <listitem>The precision of <function>fma</function>() can differ from the precision
  74                 of the expression <code>a * b + c</code>.</listitem>
  75                 <listitem><function>fma</function>() will be computed with the same precision as any
  76                 other <function>fma</function>() consumed by a <code>precise</code> variable,
  77                 giving invariant results for the same input values of <parameter>a</parameter>,
  78                 <parameter>b</parameter> and <parameter>c</parameter>.</listitem>
  79             </itemizedlist>
  80             Otherwise, in the absense of <code>precise</code> consumption, there are no
  81             special constraints on the number of operations or difference in precision between
  82             <function>fma</function>() and the expression <code>a * b + c</code>.
  83         </para>
  84     </refsect1>
  85     <refsect1 id="versions"><title>Version Support</title>
  86         <informaltable frame="topbot">
  87             #VARTABLECOLS#
  88                 <thead>
  89                     #FUNCTABLEHEADER#
  90                     <row>
  91                         <entry>fma (genType)</entry>#newin11#
  92                     </row>
  93                     <row>
  94                         <entry>fma (genDType)</entry>#newin40#
  95                     </row>
  96                 </thead>
  97             </tgroup>
  98         </informaltable>
  99     </refsect1>
 100     <refsect1 id="Copyright"><title>Copyright</title>
 101         <para>
 102             Copyright <trademark class="copyright"></trademark> 2011 Khronos Group.
 103             This material may be distributed subject to the terms and conditions set forth in
 104             the Open Publication License, v 1.0, 8 June 1999.
 105             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 106         </para>
 107     </refsect1>
 108 </refentry>