| <!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/ryu-1.0.13/src/f2s_intrinsics.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>f2s_intrinsics.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="../../ryu/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="../../ryu/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">// Translated from C to Rust. The original C code can be found at |
| // https://github.com/ulfjack/ryu and carries the following license: |
| // |
| // Copyright 2018 Ulf Adams |
| // |
| // The contents of this file may be used under the terms of the Apache License, |
| // Version 2.0. |
| // |
| // (See accompanying file LICENSE-Apache or copy at |
| // http://www.apache.org/licenses/LICENSE-2.0) |
| // |
| // Alternatively, the contents of this file may be used under the terms of |
| // the Boost Software License, Version 1.0. |
| // (See accompanying file LICENSE-Boost or copy at |
| // https://www.boost.org/LICENSE_1_0.txt) |
| // |
| // Unless required by applicable law or agreed to in writing, this software |
| // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. |
| |
| </span><span class="kw">use </span><span class="kw">crate</span>::d2s; |
| |
| <span class="kw">pub const </span>FLOAT_POW5_INV_BITCOUNT: i32 = d2s::DOUBLE_POW5_INV_BITCOUNT - <span class="number">64</span>; |
| <span class="kw">pub const </span>FLOAT_POW5_BITCOUNT: i32 = d2s::DOUBLE_POW5_BITCOUNT - <span class="number">64</span>; |
| |
| <span class="attribute">#[cfg_attr(feature = <span class="string">"no-panic"</span>, inline)] |
| </span><span class="kw">fn </span>pow5factor_32(<span class="kw-2">mut </span>value: u32) -> u32 { |
| <span class="kw">let </span><span class="kw-2">mut </span>count = <span class="number">0u32</span>; |
| <span class="kw">loop </span>{ |
| <span class="macro">debug_assert!</span>(value != <span class="number">0</span>); |
| <span class="kw">let </span>q = value / <span class="number">5</span>; |
| <span class="kw">let </span>r = value % <span class="number">5</span>; |
| <span class="kw">if </span>r != <span class="number">0 </span>{ |
| <span class="kw">break</span>; |
| } |
| value = q; |
| count += <span class="number">1</span>; |
| } |
| count |
| } |
| |
| <span class="comment">// Returns true if value is divisible by 5^p. |
| </span><span class="attribute">#[cfg_attr(feature = <span class="string">"no-panic"</span>, inline)] |
| </span><span class="kw">pub fn </span>multiple_of_power_of_5_32(value: u32, p: u32) -> bool { |
| pow5factor_32(value) >= p |
| } |
| |
| <span class="comment">// Returns true if value is divisible by 2^p. |
| </span><span class="attribute">#[cfg_attr(feature = <span class="string">"no-panic"</span>, inline)] |
| </span><span class="kw">pub fn </span>multiple_of_power_of_2_32(value: u32, p: u32) -> bool { |
| <span class="comment">// __builtin_ctz doesn't appear to be faster here. |
| </span>(value & ((<span class="number">1u32 </span><< p) - <span class="number">1</span>)) == <span class="number">0 |
| </span>} |
| |
| <span class="comment">// It seems to be slightly faster to avoid uint128_t here, although the |
| // generated code for uint128_t looks slightly nicer. |
| </span><span class="attribute">#[cfg_attr(feature = <span class="string">"no-panic"</span>, inline)] |
| </span><span class="kw">fn </span>mul_shift_32(m: u32, factor: u64, shift: i32) -> u32 { |
| <span class="macro">debug_assert!</span>(shift > <span class="number">32</span>); |
| |
| <span class="comment">// The casts here help MSVC to avoid calls to the __allmul library |
| // function. |
| </span><span class="kw">let </span>factor_lo = factor <span class="kw">as </span>u32; |
| <span class="kw">let </span>factor_hi = (factor >> <span class="number">32</span>) <span class="kw">as </span>u32; |
| <span class="kw">let </span>bits0 = m <span class="kw">as </span>u64 * factor_lo <span class="kw">as </span>u64; |
| <span class="kw">let </span>bits1 = m <span class="kw">as </span>u64 * factor_hi <span class="kw">as </span>u64; |
| |
| <span class="kw">let </span>sum = (bits0 >> <span class="number">32</span>) + bits1; |
| <span class="kw">let </span>shifted_sum = sum >> (shift - <span class="number">32</span>); |
| <span class="macro">debug_assert!</span>(shifted_sum <= u32::max_value() <span class="kw">as </span>u64); |
| shifted_sum <span class="kw">as </span>u32 |
| } |
| |
| <span class="attribute">#[cfg_attr(feature = <span class="string">"no-panic"</span>, inline)] |
| </span><span class="kw">pub fn </span>mul_pow5_inv_div_pow2(m: u32, q: u32, j: i32) -> u32 { |
| <span class="attribute">#[cfg(feature = <span class="string">"small"</span>)] |
| </span>{ |
| <span class="comment">// The inverse multipliers are defined as [2^x / 5^y] + 1; the upper 64 |
| // bits from the double lookup table are the correct bits for [2^x / |
| // 5^y], so we have to add 1 here. Note that we rely on the fact that |
| // the added 1 that's already stored in the table never overflows into |
| // the upper 64 bits. |
| </span><span class="kw">let </span>pow5 = <span class="kw">unsafe </span>{ d2s::compute_inv_pow5(q) }; |
| mul_shift_32(m, pow5.<span class="number">1 </span>+ <span class="number">1</span>, j) |
| } |
| |
| <span class="attribute">#[cfg(not(feature = <span class="string">"small"</span>))] |
| </span>{ |
| <span class="macro">debug_assert!</span>(q < d2s::DOUBLE_POW5_INV_SPLIT.len() <span class="kw">as </span>u32); |
| <span class="kw">unsafe </span>{ |
| mul_shift_32( |
| m, |
| d2s::DOUBLE_POW5_INV_SPLIT.get_unchecked(q <span class="kw">as </span>usize).<span class="number">1 </span>+ <span class="number">1</span>, |
| j, |
| ) |
| } |
| } |
| } |
| |
| <span class="attribute">#[cfg_attr(feature = <span class="string">"no-panic"</span>, inline)] |
| </span><span class="kw">pub fn </span>mul_pow5_div_pow2(m: u32, i: u32, j: i32) -> u32 { |
| <span class="attribute">#[cfg(feature = <span class="string">"small"</span>)] |
| </span>{ |
| <span class="kw">let </span>pow5 = <span class="kw">unsafe </span>{ d2s::compute_pow5(i) }; |
| mul_shift_32(m, pow5.<span class="number">1</span>, j) |
| } |
| |
| <span class="attribute">#[cfg(not(feature = <span class="string">"small"</span>))] |
| </span>{ |
| <span class="macro">debug_assert!</span>(i < d2s::DOUBLE_POW5_SPLIT.len() <span class="kw">as </span>u32); |
| <span class="kw">unsafe </span>{ mul_shift_32(m, d2s::DOUBLE_POW5_SPLIT.get_unchecked(i <span class="kw">as </span>usize).<span class="number">1</span>, j) } |
| } |
| } |
| </code></pre></div> |
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