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<table class="head">
<tr>
<td class="head-ltitle">Q_QADDI(3)</td>
<td class="head-vol">Library Functions Manual</td>
<td class="head-rtitle">Q_QADDI(3)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">Q_QADDI</code>, <code class="Nm">Q_QDIVI</code>,
<code class="Nm">Q_QMULI</code>, <code class="Nm">Q_QSUBI</code>,
<code class="Nm">Q_QFRACI</code>, <code class="Nm">Q_QCPYVALI</code>
— <span class="Nd">fixed-point math functions which apply integers to
a Q number</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
<<a class="In">sys/qmath.h</a>></code></p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">Q_QADDI</code>(<var class="Fa" style="white-space: nowrap;">QTYPE
*a</var>, <var class="Fa" style="white-space: nowrap;">ITYPE b</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">Q_QDIVI</code>(<var class="Fa" style="white-space: nowrap;">QTYPE
*a</var>, <var class="Fa" style="white-space: nowrap;">ITYPE b</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">Q_QMULI</code>(<var class="Fa" style="white-space: nowrap;">QTYPE
*a</var>, <var class="Fa" style="white-space: nowrap;">ITYPE b</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">Q_QSUBI</code>(<var class="Fa" style="white-space: nowrap;">QTYPE
*a</var>, <var class="Fa" style="white-space: nowrap;">ITYPE b</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">Q_QFRACI</code>(<var class="Fa" style="white-space: nowrap;">QTYPE
*q</var>, <var class="Fa" style="white-space: nowrap;">ITYPE n</var>,
<var class="Fa" style="white-space: nowrap;">ITYPE d</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">Q_QCPYVALI</code>(<var class="Fa" style="white-space: nowrap;">QTYPE
*q</var>, <var class="Fa" style="white-space: nowrap;">ITYPE i</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The
<a class="permalink" href="#Q_QADDI"><code class="Fn" id="Q_QADDI">Q_QADDI</code></a>(),
<a class="permalink" href="#Q_QDIVI"><code class="Fn" id="Q_QDIVI">Q_QDIVI</code></a>(),
<a class="permalink" href="#Q_QMULI"><code class="Fn" id="Q_QMULI">Q_QMULI</code></a>()
and
<a class="permalink" href="#Q_QSUBI"><code class="Fn" id="Q_QSUBI">Q_QSUBI</code></a>()
functions add, divide, multiply or subtract <var class="Fa">b</var>
to/by/from <var class="Fa">a</var> respectively, storing the result in
<var class="Fa">a</var>.</p>
<p class="Pp" id="Q_QFRACI">The
<a class="permalink" href="#Q_QFRACI"><code class="Fn">Q_QFRACI</code></a>()
function computes the fraction <var class="Fa">n</var> divided by
<var class="Fa">d</var> and stores the fixed-point result in
<var class="Fa">q</var>.</p>
<p class="Pp" id="Q_QCPYVALI">The
<a class="permalink" href="#Q_QCPYVALI"><code class="Fn">Q_QCPYVALI</code></a>()
function overwrites <var class="Fa">q</var>'s integer and fractional bits
with the Q representation of integer value <var class="Fa">i</var>.</p>
<p class="Pp">All of those functions operate on the following data types:
<var class="Vt">s8q_t</var>, <var class="Vt">u8q_t</var>,
<var class="Vt">s16q_t</var>, <var class="Vt">u16q_t</var>,
<var class="Vt">s32q_t</var>, <var class="Vt">u32q_t</var>,
<var class="Vt">s64q_t</var>, and <var class="Vt">u64q_t</var>, which are
referred to generically as <var class="Fa">QTYPE</var>. The
<var class="Fa">ITYPE</var> refers to the <a class="Xr">stdint(7)</a>
integer types.</p>
<p class="Pp">For more details, see <a class="Xr">qmath(3)</a>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="RETURN_VALUES"><a class="permalink" href="#RETURN_VALUES">RETURN
VALUES</a></h1>
<p class="Pp"><code class="Fn">Q_QADDI</code>(),
<code class="Fn">Q_QDIVI</code>(), <code class="Fn">Q_QMULI</code>(),
<code class="Fn">Q_QSUBI</code>(), <code class="Fn">Q_QFRACI</code>() and
<code class="Fn">Q_QCPYVALI</code>() functions return 0 on success, or an
errno on failure. <code class="Er">EINVAL</code> is returned for
divide-by-zero. <code class="Er">EOVERFLOW</code> and
<code class="Er">ERANGE</code> are returned for overflow and underflow
respectively.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">errno(2)</a>, <a class="Xr">qmath(3)</a>,
<a class="Xr">stdint(7)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <a class="Xr">qmath(3)</a> functions first appeared in
<span class="Ux">FreeBSD 13.0</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The <a class="Xr">qmath(3)</a> functions and this manual page were
written by <span class="An">Lawrence Stewart</span>
<<a class="Mt" href="mailto:lstewart@FreeBSD.org">lstewart@FreeBSD.org</a>>
and sponsored by Netflix, Inc.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">July 8, 2018</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
