<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source to the Rust file `/home/mrh/.cargo/registry/src/github.com-1ecc6299db9ec823/libm-0.1.4/src/math/tanf.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>tanf.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><script src="../../../storage.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="shortcut icon" href="../../../favicon.ico"><style type="text/css">#crate-search{background-image:url("../../../down-arrow.svg");}</style></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../libm/index.html'><div class='logo-container'><img src='../../../rust-logo.png' alt='logo'></div></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span>
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</pre><div class="example-wrap"><pre class="rust ">
<span class="comment">/* origin: FreeBSD /usr/src/lib/msun/src/s_tanf.c */</span>
<span class="comment">/*
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
* Optimized by Bruce D. Evans.
*/</span>
<span class="comment">/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/</span>
<span class="kw">use</span> <span class="kw">super</span>::{<span class="ident">k_tanf</span>, <span class="ident">rem_pio2f</span>};
<span class="kw">use</span> <span class="ident">core</span>::<span class="ident">f64</span>::<span class="ident">consts</span>::<span class="ident">FRAC_PI_2</span>;
<span class="comment">/* Small multiples of pi/2 rounded to double precision. */</span>
<span class="kw">const</span> <span class="ident">T1_PIO2</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="number">1.</span> <span class="op">*</span> <span class="ident">FRAC_PI_2</span>; <span class="comment">/* 0x3FF921FB, 0x54442D18 */</span>
<span class="kw">const</span> <span class="ident">T2_PIO2</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="number">2.</span> <span class="op">*</span> <span class="ident">FRAC_PI_2</span>; <span class="comment">/* 0x400921FB, 0x54442D18 */</span>
<span class="kw">const</span> <span class="ident">T3_PIO2</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="number">3.</span> <span class="op">*</span> <span class="ident">FRAC_PI_2</span>; <span class="comment">/* 0x4012D97C, 0x7F3321D2 */</span>
<span class="kw">const</span> <span class="ident">T4_PIO2</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="number">4.</span> <span class="op">*</span> <span class="ident">FRAC_PI_2</span>; <span class="comment">/* 0x401921FB, 0x54442D18 */</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">all</span>(<span class="ident">test</span>, <span class="ident">assert_no_panic</span>), <span class="ident">no_panic</span>::<span class="ident">no_panic</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">tanf</span>(<span class="ident">x</span>: <span class="ident">f32</span>) <span class="op">-</span><span class="op">></span> <span class="ident">f32</span> {
<span class="kw">let</span> <span class="ident">x64</span> <span class="op">=</span> <span class="ident">x</span> <span class="kw">as</span> <span class="ident">f64</span>;
<span class="kw">let</span> <span class="ident">x1p120</span> <span class="op">=</span> <span class="ident">f32</span>::<span class="ident">from_bits</span>(<span class="number">0x7b800000</span>); <span class="comment">// 0x1p120f === 2 ^ 120</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">ix</span> <span class="op">=</span> <span class="ident">x</span>.<span class="ident">to_bits</span>();
<span class="kw">let</span> <span class="ident">sign</span> <span class="op">=</span> (<span class="ident">ix</span> <span class="op">></span><span class="op">></span> <span class="number">31</span>) <span class="op">!</span><span class="op">=</span> <span class="number">0</span>;
<span class="ident">ix</span> <span class="kw-2">&</span><span class="op">=</span> <span class="number">0x7fffffff</span>;
<span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span><span class="op">=</span> <span class="number">0x3f490fda</span> {
<span class="comment">/* |x| ~<= pi/4 */</span>
<span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span> <span class="number">0x39800000</span> {
<span class="comment">/* |x| < 2**-12 */</span>
<span class="comment">/* raise inexact if x!=0 and underflow if subnormal */</span>
<span class="macro">force_eval</span><span class="macro">!</span>(<span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span> <span class="number">0x00800000</span> {
<span class="ident">x</span> <span class="op">/</span> <span class="ident">x1p120</span>
} <span class="kw">else</span> {
<span class="ident">x</span> <span class="op">+</span> <span class="ident">x1p120</span>
});
<span class="kw">return</span> <span class="ident">x</span>;
}
<span class="kw">return</span> <span class="ident">k_tanf</span>(<span class="ident">x64</span>, <span class="bool-val">false</span>);
}
<span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span><span class="op">=</span> <span class="number">0x407b53d1</span> {
<span class="comment">/* |x| ~<= 5*pi/4 */</span>
<span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span><span class="op">=</span> <span class="number">0x4016cbe3</span> {
<span class="comment">/* |x| ~<= 3pi/4 */</span>
<span class="kw">return</span> <span class="ident">k_tanf</span>(<span class="kw">if</span> <span class="ident">sign</span> { <span class="ident">x64</span> <span class="op">+</span> <span class="ident">T1_PIO2</span> } <span class="kw">else</span> { <span class="ident">x64</span> <span class="op">-</span> <span class="ident">T1_PIO2</span> }, <span class="bool-val">true</span>);
} <span class="kw">else</span> {
<span class="kw">return</span> <span class="ident">k_tanf</span>(<span class="kw">if</span> <span class="ident">sign</span> { <span class="ident">x64</span> <span class="op">+</span> <span class="ident">T2_PIO2</span> } <span class="kw">else</span> { <span class="ident">x64</span> <span class="op">-</span> <span class="ident">T2_PIO2</span> }, <span class="bool-val">false</span>);
}
}
<span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span><span class="op">=</span> <span class="number">0x40e231d5</span> {
<span class="comment">/* |x| ~<= 9*pi/4 */</span>
<span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span><span class="op">=</span> <span class="number">0x40afeddf</span> {
<span class="comment">/* |x| ~<= 7*pi/4 */</span>
<span class="kw">return</span> <span class="ident">k_tanf</span>(<span class="kw">if</span> <span class="ident">sign</span> { <span class="ident">x64</span> <span class="op">+</span> <span class="ident">T3_PIO2</span> } <span class="kw">else</span> { <span class="ident">x64</span> <span class="op">-</span> <span class="ident">T3_PIO2</span> }, <span class="bool-val">true</span>);
} <span class="kw">else</span> {
<span class="kw">return</span> <span class="ident">k_tanf</span>(<span class="kw">if</span> <span class="ident">sign</span> { <span class="ident">x64</span> <span class="op">+</span> <span class="ident">T4_PIO2</span> } <span class="kw">else</span> { <span class="ident">x64</span> <span class="op">-</span> <span class="ident">T4_PIO2</span> }, <span class="bool-val">false</span>);
}
}
<span class="comment">/* tan(Inf or NaN) is NaN */</span>
<span class="kw">if</span> <span class="ident">ix</span> <span class="op">></span><span class="op">=</span> <span class="number">0x7f800000</span> {
<span class="kw">return</span> <span class="ident">x</span> <span class="op">-</span> <span class="ident">x</span>;
}
<span class="comment">/* argument reduction */</span>
<span class="kw">let</span> (<span class="ident">n</span>, <span class="ident">y</span>) <span class="op">=</span> <span class="ident">rem_pio2f</span>(<span class="ident">x</span>);
<span class="ident">k_tanf</span>(<span class="ident">y</span>, <span class="ident">n</span> <span class="op">&</span> <span class="number">1</span> <span class="op">!</span><span class="op">=</span> <span class="number">0</span>)
}
</pre></div>
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