<!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 `libcore/../stdsimd/coresimd/x86/abm.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>abm.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><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></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='../../../../../../core/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></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"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><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><pre class="rust ">
<span class="doccomment">//! Advanced Bit Manipulation (ABM) instructions</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! The POPCNT and LZCNT have their own CPUID bits to indicate support.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! The references are:</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! - [Intel 64 and IA-32 Architectures Software Developer's Manual Volume 2:</span>
<span class="doccomment">//! Instruction Set Reference, A-Z][intel64_ref].</span>
<span class="doccomment">//! - [AMD64 Architecture Programmer's Manual, Volume 3: General-Purpose and</span>
<span class="doccomment">//! System Instructions][amd64_ref].</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! [Wikipedia][wikipedia_bmi] provides a quick overview of the instructions</span>
<span class="doccomment">//! available.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! [intel64_ref]: http://www.intel.de/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf</span>
<span class="doccomment">//! [amd64_ref]: http://support.amd.com/TechDocs/24594.pdf</span>
<span class="doccomment">//! [wikipedia_bmi]:</span>
<span class="doccomment">//! https://en.wikipedia.org/wiki/Bit_Manipulation_Instruction_Sets#ABM_.28Advanced_Bit_Manipulation.29</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span>
<span class="kw">use</span> <span class="ident">stdsimd_test</span>::<span class="ident">assert_instr</span>;
<span class="doccomment">/// Counts the leading most significant zero bits.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// When the operand is zero, it returns its size in bits.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_lzcnt_u32)</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">target_feature</span>(<span class="ident">enable</span> <span class="op">=</span> <span class="string">"lzcnt"</span>)]</span>
<span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">test</span>, <span class="ident">assert_instr</span>(<span class="ident">lzcnt</span>))]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"simd_x86"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.27.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">_lzcnt_u32</span>(<span class="ident">x</span>: <span class="ident">u32</span>) <span class="op">-></span> <span class="ident">u32</span> {
<span class="ident">x</span>.<span class="ident">leading_zeros</span>()
}
<span class="doccomment">/// Counts the bits that are set.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_popcnt32)</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">target_feature</span>(<span class="ident">enable</span> <span class="op">=</span> <span class="string">"popcnt"</span>)]</span>
<span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">test</span>, <span class="ident">assert_instr</span>(<span class="ident">popcnt</span>))]</span>
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"simd_x86"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.27.0"</span>)]</span>
<span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">_popcnt32</span>(<span class="ident">x</span>: <span class="ident">i32</span>) <span class="op">-></span> <span class="ident">i32</span> {
<span class="ident">x</span>.<span class="ident">count_ones</span>() <span class="kw">as</span> <span class="ident">i32</span>
}
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span>
<span class="kw">mod</span> <span class="ident">tests</span> {
<span class="kw">use</span> <span class="ident">stdsimd_test</span>::<span class="ident">simd_test</span>;
<span class="kw">use</span> <span class="ident">coresimd</span>::<span class="ident">x86</span>::<span class="kw-2">*</span>;
<span class="attribute">#[<span class="ident">simd_test</span>(<span class="ident">enable</span> <span class="op">=</span> <span class="string">"lzcnt"</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">test_lzcnt_u32</span>() {
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">_lzcnt_u32</span>(<span class="number">0b0101_1010</span>), <span class="number">25</span>);
}
<span class="attribute">#[<span class="ident">simd_test</span>(<span class="ident">enable</span> <span class="op">=</span> <span class="string">"popcnt"</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">test_popcnt32</span>() {
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">_popcnt32</span>(<span class="number">0b0101_1010</span>), <span class="number">4</span>);
}
}
</pre>
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