| <!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 of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/libm-0.2.7/src/math/sincosf.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>sincosf.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../libm/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../libm/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="comment">/* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */ |
| /* |
| * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
| * Optimized by Bruce D. Evans. |
| */ |
| /* |
| * ==================================================== |
| * 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 super</span>::{k_cosf, k_sinf, rem_pio2f}; |
| |
| <span class="comment">/* Small multiples of pi/2 rounded to double precision. */ |
| </span><span class="kw">const </span>PI_2: f32 = <span class="number">0.5 </span>* <span class="number">3.1415926535897931160E+00</span>; |
| <span class="kw">const </span>S1PIO2: f32 = <span class="number">1.0 </span>* PI_2; <span class="comment">/* 0x3FF921FB, 0x54442D18 */ |
| </span><span class="kw">const </span>S2PIO2: f32 = <span class="number">2.0 </span>* PI_2; <span class="comment">/* 0x400921FB, 0x54442D18 */ |
| </span><span class="kw">const </span>S3PIO2: f32 = <span class="number">3.0 </span>* PI_2; <span class="comment">/* 0x4012D97C, 0x7F3321D2 */ |
| </span><span class="kw">const </span>S4PIO2: f32 = <span class="number">4.0 </span>* PI_2; <span class="comment">/* 0x401921FB, 0x54442D18 */ |
| |
| </span><span class="attribute">#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
| </span><span class="kw">pub fn </span>sincosf(x: f32) -> (f32, f32) { |
| <span class="kw">let </span>s: f32; |
| <span class="kw">let </span>c: f32; |
| <span class="kw">let </span><span class="kw-2">mut </span>ix: u32; |
| <span class="kw">let </span>sign: bool; |
| |
| ix = x.to_bits(); |
| sign = (ix >> <span class="number">31</span>) != <span class="number">0</span>; |
| ix &= <span class="number">0x7fffffff</span>; |
| |
| <span class="comment">/* |x| ~<= pi/4 */ |
| </span><span class="kw">if </span>ix <= <span class="number">0x3f490fda </span>{ |
| <span class="comment">/* |x| < 2**-12 */ |
| </span><span class="kw">if </span>ix < <span class="number">0x39800000 </span>{ |
| <span class="comment">/* raise inexact if x!=0 and underflow if subnormal */ |
| |
| </span><span class="kw">let </span>x1p120 = f32::from_bits(<span class="number">0x7b800000</span>); <span class="comment">// 0x1p120 == 2^120 |
| </span><span class="kw">if </span>ix < <span class="number">0x00100000 </span>{ |
| <span class="macro">force_eval!</span>(x / x1p120); |
| } <span class="kw">else </span>{ |
| <span class="macro">force_eval!</span>(x + x1p120); |
| } |
| <span class="kw">return </span>(x, <span class="number">1.0</span>); |
| } |
| <span class="kw">return </span>(k_sinf(x <span class="kw">as </span>f64), k_cosf(x <span class="kw">as </span>f64)); |
| } |
| |
| <span class="comment">/* |x| ~<= 5*pi/4 */ |
| </span><span class="kw">if </span>ix <= <span class="number">0x407b53d1 </span>{ |
| <span class="kw">if </span>ix <= <span class="number">0x4016cbe3 </span>{ |
| <span class="comment">/* |x| ~<= 3pi/4 */ |
| </span><span class="kw">if </span>sign { |
| s = -k_cosf((x + S1PIO2) <span class="kw">as </span>f64); |
| c = k_sinf((x + S1PIO2) <span class="kw">as </span>f64); |
| } <span class="kw">else </span>{ |
| s = k_cosf((S1PIO2 - x) <span class="kw">as </span>f64); |
| c = k_sinf((S1PIO2 - x) <span class="kw">as </span>f64); |
| } |
| } |
| <span class="comment">/* -sin(x+c) is not correct if x+c could be 0: -0 vs +0 */ |
| </span><span class="kw">else </span>{ |
| <span class="kw">if </span>sign { |
| s = -k_sinf((x + S2PIO2) <span class="kw">as </span>f64); |
| c = -k_cosf((x + S2PIO2) <span class="kw">as </span>f64); |
| } <span class="kw">else </span>{ |
| s = -k_sinf((x - S2PIO2) <span class="kw">as </span>f64); |
| c = -k_cosf((x - S2PIO2) <span class="kw">as </span>f64); |
| } |
| } |
| |
| <span class="kw">return </span>(s, c); |
| } |
| |
| <span class="comment">/* |x| ~<= 9*pi/4 */ |
| </span><span class="kw">if </span>ix <= <span class="number">0x40e231d5 </span>{ |
| <span class="kw">if </span>ix <= <span class="number">0x40afeddf </span>{ |
| <span class="comment">/* |x| ~<= 7*pi/4 */ |
| </span><span class="kw">if </span>sign { |
| s = k_cosf((x + S3PIO2) <span class="kw">as </span>f64); |
| c = -k_sinf((x + S3PIO2) <span class="kw">as </span>f64); |
| } <span class="kw">else </span>{ |
| s = -k_cosf((x - S3PIO2) <span class="kw">as </span>f64); |
| c = k_sinf((x - S3PIO2) <span class="kw">as </span>f64); |
| } |
| } <span class="kw">else </span>{ |
| <span class="kw">if </span>sign { |
| s = k_sinf((x + S4PIO2) <span class="kw">as </span>f64); |
| c = k_cosf((x + S4PIO2) <span class="kw">as </span>f64); |
| } <span class="kw">else </span>{ |
| s = k_sinf((x - S4PIO2) <span class="kw">as </span>f64); |
| c = k_cosf((x - S4PIO2) <span class="kw">as </span>f64); |
| } |
| } |
| |
| <span class="kw">return </span>(s, c); |
| } |
| |
| <span class="comment">/* sin(Inf or NaN) is NaN */ |
| </span><span class="kw">if </span>ix >= <span class="number">0x7f800000 </span>{ |
| <span class="kw">let </span>rv = x - x; |
| <span class="kw">return </span>(rv, rv); |
| } |
| |
| <span class="comment">/* general argument reduction needed */ |
| </span><span class="kw">let </span>(n, y) = rem_pio2f(x); |
| s = k_sinf(y); |
| c = k_cosf(y); |
| <span class="kw">match </span>n & <span class="number">3 </span>{ |
| <span class="number">0 </span>=> (s, c), |
| <span class="number">1 </span>=> (c, -s), |
| <span class="number">2 </span>=> (-s, -c), |
| <span class="number">3 </span>=> (-c, s), |
| <span class="attribute">#[cfg(debug_assertions)] |
| </span><span class="kw">_ </span>=> <span class="macro">unreachable!</span>(), |
| <span class="attribute">#[cfg(not(debug_assertions))] |
| </span><span class="kw">_ </span>=> (<span class="number">0.0</span>, <span class="number">1.0</span>), |
| } |
| } |
| |
| <span class="comment">// PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520 |
| </span><span class="attribute">#[cfg(not(target_arch = <span class="string">"powerpc64"</span>))] |
| #[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use </span><span class="kw">super</span>::sincosf; |
| <span class="kw">use </span><span class="kw">crate</span>::_eqf; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>with_pi() { |
| <span class="kw">let </span>(s, c) = sincosf(core::f32::consts::PI); |
| _eqf(s.abs(), <span class="number">0.0</span>).unwrap(); |
| _eqf(c, -<span class="number">1.0</span>).unwrap(); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>rotational_symmetry() { |
| <span class="kw">use </span>core::f32::consts::PI; |
| <span class="kw">const </span>N: usize = <span class="number">24</span>; |
| <span class="kw">for </span>n <span class="kw">in </span><span class="number">0</span>..N { |
| <span class="kw">let </span>theta = <span class="number">2. </span>* PI * (n <span class="kw">as </span>f32) / (N <span class="kw">as </span>f32); |
| <span class="kw">let </span>(s, c) = sincosf(theta); |
| <span class="kw">let </span>(s_plus, c_plus) = sincosf(theta + <span class="number">2. </span>* PI); |
| <span class="kw">let </span>(s_minus, c_minus) = sincosf(theta - <span class="number">2. </span>* PI); |
| |
| <span class="kw">const </span>TOLERANCE: f32 = <span class="number">1e-6</span>; |
| <span class="macro">assert!</span>( |
| (s - s_plus).abs() < TOLERANCE, |
| <span class="string">"|{} - {}| = {} >= {}"</span>, |
| s, |
| s_plus, |
| (s - s_plus).abs(), |
| TOLERANCE |
| ); |
| <span class="macro">assert!</span>( |
| (s - s_minus).abs() < TOLERANCE, |
| <span class="string">"|{} - {}| = {} >= {}"</span>, |
| s, |
| s_minus, |
| (s - s_minus).abs(), |
| TOLERANCE |
| ); |
| <span class="macro">assert!</span>( |
| (c - c_plus).abs() < TOLERANCE, |
| <span class="string">"|{} - {}| = {} >= {}"</span>, |
| c, |
| c_plus, |
| (c - c_plus).abs(), |
| TOLERANCE |
| ); |
| <span class="macro">assert!</span>( |
| (c - c_minus).abs() < TOLERANCE, |
| <span class="string">"|{} - {}| = {} >= {}"</span>, |
| c, |
| c_minus, |
| (c - c_minus).abs(), |
| TOLERANCE |
| ); |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="libm" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |