| <!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/remquo.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>remquo.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="attribute">#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
| </span><span class="kw">pub fn </span>remquo(<span class="kw-2">mut </span>x: f64, <span class="kw-2">mut </span>y: f64) -> (f64, i32) { |
| <span class="kw">let </span>ux: u64 = x.to_bits(); |
| <span class="kw">let </span><span class="kw-2">mut </span>uy: u64 = y.to_bits(); |
| <span class="kw">let </span><span class="kw-2">mut </span>ex = ((ux >> <span class="number">52</span>) & <span class="number">0x7ff</span>) <span class="kw">as </span>i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>ey = ((uy >> <span class="number">52</span>) & <span class="number">0x7ff</span>) <span class="kw">as </span>i32; |
| <span class="kw">let </span>sx = (ux >> <span class="number">63</span>) != <span class="number">0</span>; |
| <span class="kw">let </span>sy = (uy >> <span class="number">63</span>) != <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>q: u32; |
| <span class="kw">let </span><span class="kw-2">mut </span>i: u64; |
| <span class="kw">let </span><span class="kw-2">mut </span>uxi: u64 = ux; |
| |
| <span class="kw">if </span>(uy << <span class="number">1</span>) == <span class="number">0 </span>|| y.is_nan() || ex == <span class="number">0x7ff </span>{ |
| <span class="kw">return </span>((x * y) / (x * y), <span class="number">0</span>); |
| } |
| <span class="kw">if </span>(ux << <span class="number">1</span>) == <span class="number">0 </span>{ |
| <span class="kw">return </span>(x, <span class="number">0</span>); |
| } |
| |
| <span class="comment">/* normalize x and y */ |
| </span><span class="kw">if </span>ex == <span class="number">0 </span>{ |
| i = uxi << <span class="number">12</span>; |
| <span class="kw">while </span>(i >> <span class="number">63</span>) == <span class="number">0 </span>{ |
| ex -= <span class="number">1</span>; |
| i <<= <span class="number">1</span>; |
| } |
| uxi <<= -ex + <span class="number">1</span>; |
| } <span class="kw">else </span>{ |
| uxi &= (!<span class="number">0</span>) >> <span class="number">12</span>; |
| uxi |= <span class="number">1 </span><< <span class="number">52</span>; |
| } |
| <span class="kw">if </span>ey == <span class="number">0 </span>{ |
| i = uy << <span class="number">12</span>; |
| <span class="kw">while </span>(i >> <span class="number">63</span>) == <span class="number">0 </span>{ |
| ey -= <span class="number">1</span>; |
| i <<= <span class="number">1</span>; |
| } |
| uy <<= -ey + <span class="number">1</span>; |
| } <span class="kw">else </span>{ |
| uy &= (!<span class="number">0</span>) >> <span class="number">12</span>; |
| uy |= <span class="number">1 </span><< <span class="number">52</span>; |
| } |
| |
| q = <span class="number">0</span>; |
| |
| <span class="kw">if </span>ex + <span class="number">1 </span>!= ey { |
| <span class="kw">if </span>ex < ey { |
| <span class="kw">return </span>(x, <span class="number">0</span>); |
| } |
| <span class="comment">/* x mod y */ |
| </span><span class="kw">while </span>ex > ey { |
| i = uxi.wrapping_sub(uy); |
| <span class="kw">if </span>(i >> <span class="number">63</span>) == <span class="number">0 </span>{ |
| uxi = i; |
| q += <span class="number">1</span>; |
| } |
| uxi <<= <span class="number">1</span>; |
| q <<= <span class="number">1</span>; |
| ex -= <span class="number">1</span>; |
| } |
| i = uxi.wrapping_sub(uy); |
| <span class="kw">if </span>(i >> <span class="number">63</span>) == <span class="number">0 </span>{ |
| uxi = i; |
| q += <span class="number">1</span>; |
| } |
| <span class="kw">if </span>uxi == <span class="number">0 </span>{ |
| ex = -<span class="number">60</span>; |
| } <span class="kw">else </span>{ |
| <span class="kw">while </span>(uxi >> <span class="number">52</span>) == <span class="number">0 </span>{ |
| uxi <<= <span class="number">1</span>; |
| ex -= <span class="number">1</span>; |
| } |
| } |
| } |
| |
| <span class="comment">/* scale result and decide between |x| and |x|-|y| */ |
| </span><span class="kw">if </span>ex > <span class="number">0 </span>{ |
| uxi -= <span class="number">1 </span><< <span class="number">52</span>; |
| uxi |= (ex <span class="kw">as </span>u64) << <span class="number">52</span>; |
| } <span class="kw">else </span>{ |
| uxi >>= -ex + <span class="number">1</span>; |
| } |
| x = f64::from_bits(uxi); |
| <span class="kw">if </span>sy { |
| y = -y; |
| } |
| <span class="kw">if </span>ex == ey || (ex + <span class="number">1 </span>== ey && (<span class="number">2.0 </span>* x > y || (<span class="number">2.0 </span>* x == y && (q % <span class="number">2</span>) != <span class="number">0</span>))) { |
| x -= y; |
| <span class="comment">// TODO: this matches musl behavior, but it is incorrect |
| </span>q = q.wrapping_add(<span class="number">1</span>); |
| } |
| q &= <span class="number">0x7fffffff</span>; |
| <span class="kw">let </span>quo = <span class="kw">if </span>sx ^ sy { -(q <span class="kw">as </span>i32) } <span class="kw">else </span>{ q <span class="kw">as </span>i32 }; |
| <span class="kw">if </span>sx { |
| (-x, quo) |
| } <span class="kw">else </span>{ |
| (x, quo) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use </span><span class="kw">super</span>::remquo; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_q_overflow() { |
| <span class="comment">// 0xc000000000000001, 0x04c0000000000004 |
| </span><span class="kw">let _ </span>= remquo(-<span class="number">2.0000000000000004</span>, <span class="number">8.406091369059082e-286</span>); |
| } |
| } |
| </code></pre></div> |
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