| <!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 `/home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/libm-0.2.1/src/math/powf.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>powf.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" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../ayu.css" disabled><link rel="stylesheet" type="text/css" href="../../../dark.css" disabled><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script src="../../../crates.js"></script><script defer src="../../../main.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script> |
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| </pre><pre class="rust"><code><span class="comment">/* origin: FreeBSD /usr/src/lib/msun/src/e_powf.c */</span> |
| <span class="comment">/* |
| * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
| */</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">fabsf</span>, <span class="ident">scalbnf</span>, <span class="ident">sqrtf</span>}; |
| |
| <span class="kw">const</span> <span class="ident">BP</span>: [<span class="ident">f32</span>; <span class="number">2</span>] <span class="op">=</span> [<span class="number">1.0</span>, <span class="number">1.5</span>]; |
| <span class="kw">const</span> <span class="ident">DP_H</span>: [<span class="ident">f32</span>; <span class="number">2</span>] <span class="op">=</span> [<span class="number">0.0</span>, <span class="number">5.84960938e-01</span>]; <span class="comment">/* 0x3f15c000 */</span> |
| <span class="kw">const</span> <span class="ident">DP_L</span>: [<span class="ident">f32</span>; <span class="number">2</span>] <span class="op">=</span> [<span class="number">0.0</span>, <span class="number">1.56322085e-06</span>]; <span class="comment">/* 0x35d1cfdc */</span> |
| <span class="kw">const</span> <span class="ident">TWO24</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">16777216.0</span>; <span class="comment">/* 0x4b800000 */</span> |
| <span class="kw">const</span> <span class="ident">HUGE</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">1.0e30</span>; |
| <span class="kw">const</span> <span class="ident">TINY</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">1.0e-30</span>; |
| <span class="kw">const</span> <span class="ident">L1</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">6.0000002384e-01</span>; <span class="comment">/* 0x3f19999a */</span> |
| <span class="kw">const</span> <span class="ident">L2</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">4.2857143283e-01</span>; <span class="comment">/* 0x3edb6db7 */</span> |
| <span class="kw">const</span> <span class="ident">L3</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">3.3333334327e-01</span>; <span class="comment">/* 0x3eaaaaab */</span> |
| <span class="kw">const</span> <span class="ident">L4</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">2.7272811532e-01</span>; <span class="comment">/* 0x3e8ba305 */</span> |
| <span class="kw">const</span> <span class="ident">L5</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">2.3066075146e-01</span>; <span class="comment">/* 0x3e6c3255 */</span> |
| <span class="kw">const</span> <span class="ident">L6</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">2.0697501302e-01</span>; <span class="comment">/* 0x3e53f142 */</span> |
| <span class="kw">const</span> <span class="ident">P1</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">1.6666667163e-01</span>; <span class="comment">/* 0x3e2aaaab */</span> |
| <span class="kw">const</span> <span class="ident">P2</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="op">-</span><span class="number">2.7777778450e-03</span>; <span class="comment">/* 0xbb360b61 */</span> |
| <span class="kw">const</span> <span class="ident">P3</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">6.6137559770e-05</span>; <span class="comment">/* 0x388ab355 */</span> |
| <span class="kw">const</span> <span class="ident">P4</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="op">-</span><span class="number">1.6533901999e-06</span>; <span class="comment">/* 0xb5ddea0e */</span> |
| <span class="kw">const</span> <span class="ident">P5</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">4.1381369442e-08</span>; <span class="comment">/* 0x3331bb4c */</span> |
| <span class="kw">const</span> <span class="ident">LG2</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">6.9314718246e-01</span>; <span class="comment">/* 0x3f317218 */</span> |
| <span class="kw">const</span> <span class="ident">LG2_H</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">6.93145752e-01</span>; <span class="comment">/* 0x3f317200 */</span> |
| <span class="kw">const</span> <span class="ident">LG2_L</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">1.42860654e-06</span>; <span class="comment">/* 0x35bfbe8c */</span> |
| <span class="kw">const</span> <span class="ident">OVT</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">4.2995665694e-08</span>; <span class="comment">/* -(128-log2(ovfl+.5ulp)) */</span> |
| <span class="kw">const</span> <span class="ident">CP</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">9.6179670095e-01</span>; <span class="comment">/* 0x3f76384f =2/(3ln2) */</span> |
| <span class="kw">const</span> <span class="ident">CP_H</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">9.6191406250e-01</span>; <span class="comment">/* 0x3f764000 =12b cp */</span> |
| <span class="kw">const</span> <span class="ident">CP_L</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="op">-</span><span class="number">1.1736857402e-04</span>; <span class="comment">/* 0xb8f623c6 =tail of cp_h */</span> |
| <span class="kw">const</span> <span class="ident">IVLN2</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">1.4426950216e+00</span>; |
| <span class="kw">const</span> <span class="ident">IVLN2_H</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">1.4426879883e+00</span>; |
| <span class="kw">const</span> <span class="ident">IVLN2_L</span>: <span class="ident">f32</span> <span class="op">=</span> <span class="number">7.0526075433e-06</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::no_panic</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">powf</span>(<span class="ident">x</span>: <span class="ident">f32</span>, <span class="ident">y</span>: <span class="ident">f32</span>) -> <span class="ident">f32</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">z</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">ax</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">z_h</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">z_l</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">p_h</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">p_l</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">y1</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t1</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">t2</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">r</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">s</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">sn</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">u</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">v</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">w</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">i</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">j</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">k</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">yisint</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">n</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="ident">hx</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="ident">hy</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">ix</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="ident">iy</span>: <span class="ident">i32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">is</span>: <span class="ident">i32</span>; |
| |
| <span class="ident">hx</span> <span class="op">=</span> <span class="ident">x</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">hy</span> <span class="op">=</span> <span class="ident">y</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| |
| <span class="ident">ix</span> <span class="op">=</span> <span class="ident">hx</span> <span class="op">&</span> <span class="number">0x7fffffff</span>; |
| <span class="ident">iy</span> <span class="op">=</span> <span class="ident">hy</span> <span class="op">&</span> <span class="number">0x7fffffff</span>; |
| |
| <span class="comment">/* x**0 = 1, even if x is NaN */</span> |
| <span class="kw">if</span> <span class="ident">iy</span> <span class="op">==</span> <span class="number">0</span> { |
| <span class="kw">return</span> <span class="number">1.0</span>; |
| } |
| |
| <span class="comment">/* 1**y = 1, even if y is NaN */</span> |
| <span class="kw">if</span> <span class="ident">hx</span> <span class="op">==</span> <span class="number">0x3f800000</span> { |
| <span class="kw">return</span> <span class="number">1.0</span>; |
| } |
| |
| <span class="comment">/* NaN if either arg is NaN */</span> |
| <span class="kw">if</span> <span class="ident">ix</span> <span class="op">></span> <span class="number">0x7f800000</span> <span class="op">|</span><span class="op">|</span> <span class="ident">iy</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">y</span>; |
| } |
| |
| <span class="comment">/* determine if y is an odd int when x < 0 |
| * yisint = 0 ... y is not an integer |
| * yisint = 1 ... y is an odd int |
| * yisint = 2 ... y is an even int |
| */</span> |
| <span class="ident">yisint</span> <span class="op">=</span> <span class="number">0</span>; |
| <span class="kw">if</span> <span class="ident">hx</span> <span class="op"><</span> <span class="number">0</span> { |
| <span class="kw">if</span> <span class="ident">iy</span> <span class="op">></span><span class="op">=</span> <span class="number">0x4b800000</span> { |
| <span class="ident">yisint</span> <span class="op">=</span> <span class="number">2</span>; <span class="comment">/* even integer y */</span> |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">iy</span> <span class="op">></span><span class="op">=</span> <span class="number">0x3f800000</span> { |
| <span class="ident">k</span> <span class="op">=</span> (<span class="ident">iy</span> <span class="op">></span><span class="op">></span> <span class="number">23</span>) <span class="op">-</span> <span class="number">0x7f</span>; <span class="comment">/* exponent */</span> |
| <span class="ident">j</span> <span class="op">=</span> <span class="ident">iy</span> <span class="op">></span><span class="op">></span> (<span class="number">23</span> <span class="op">-</span> <span class="ident">k</span>); |
| <span class="kw">if</span> (<span class="ident">j</span> <span class="op"><</span><span class="op"><</span> (<span class="number">23</span> <span class="op">-</span> <span class="ident">k</span>)) <span class="op">==</span> <span class="ident">iy</span> { |
| <span class="ident">yisint</span> <span class="op">=</span> <span class="number">2</span> <span class="op">-</span> (<span class="ident">j</span> <span class="op">&</span> <span class="number">1</span>); |
| } |
| } |
| } |
| |
| <span class="comment">/* special value of y */</span> |
| <span class="kw">if</span> <span class="ident">iy</span> <span class="op">==</span> <span class="number">0x7f800000</span> { |
| <span class="comment">/* y is +-inf */</span> |
| <span class="kw">if</span> <span class="ident">ix</span> <span class="op">==</span> <span class="number">0x3f800000</span> { |
| <span class="comment">/* (-1)**+-inf is 1 */</span> |
| <span class="kw">return</span> <span class="number">1.0</span>; |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">ix</span> <span class="op">></span> <span class="number">0x3f800000</span> { |
| <span class="comment">/* (|x|>1)**+-inf = inf,0 */</span> |
| <span class="kw">return</span> <span class="kw">if</span> <span class="ident">hy</span> <span class="op">></span><span class="op">=</span> <span class="number">0</span> { <span class="ident">y</span> } <span class="kw">else</span> { <span class="number">0.0</span> }; |
| } <span class="kw">else</span> { |
| <span class="comment">/* (|x|<1)**+-inf = 0,inf */</span> |
| <span class="kw">return</span> <span class="kw">if</span> <span class="ident">hy</span> <span class="op">></span><span class="op">=</span> <span class="number">0</span> { <span class="number">0.0</span> } <span class="kw">else</span> { <span class="op">-</span><span class="ident">y</span> }; |
| } |
| } |
| <span class="kw">if</span> <span class="ident">iy</span> <span class="op">==</span> <span class="number">0x3f800000</span> { |
| <span class="comment">/* y is +-1 */</span> |
| <span class="kw">return</span> <span class="kw">if</span> <span class="ident">hy</span> <span class="op">></span><span class="op">=</span> <span class="number">0</span> { <span class="ident">x</span> } <span class="kw">else</span> { <span class="number">1.0</span> <span class="op">/</span> <span class="ident">x</span> }; |
| } |
| |
| <span class="kw">if</span> <span class="ident">hy</span> <span class="op">==</span> <span class="number">0x40000000</span> { |
| <span class="comment">/* y is 2 */</span> |
| <span class="kw">return</span> <span class="ident">x</span> <span class="op">*</span> <span class="ident">x</span>; |
| } |
| |
| <span class="kw">if</span> <span class="ident">hy</span> <span class="op">==</span> <span class="number">0x3f000000</span> |
| <span class="comment">/* y is 0.5 */</span> |
| <span class="op">&&</span> <span class="ident">hx</span> <span class="op">></span><span class="op">=</span> <span class="number">0</span> |
| { |
| <span class="comment">/* x >= +0 */</span> |
| <span class="kw">return</span> <span class="ident">sqrtf</span>(<span class="ident">x</span>); |
| } |
| |
| <span class="ident">ax</span> <span class="op">=</span> <span class="ident">fabsf</span>(<span class="ident">x</span>); |
| <span class="comment">/* special value of x */</span> |
| <span class="kw">if</span> <span class="ident">ix</span> <span class="op">==</span> <span class="number">0x7f800000</span> <span class="op">|</span><span class="op">|</span> <span class="ident">ix</span> <span class="op">==</span> <span class="number">0</span> <span class="op">|</span><span class="op">|</span> <span class="ident">ix</span> <span class="op">==</span> <span class="number">0x3f800000</span> { |
| <span class="comment">/* x is +-0,+-inf,+-1 */</span> |
| <span class="ident">z</span> <span class="op">=</span> <span class="ident">ax</span>; |
| <span class="kw">if</span> <span class="ident">hy</span> <span class="op"><</span> <span class="number">0</span> { |
| <span class="comment">/* z = (1/|x|) */</span> |
| <span class="ident">z</span> <span class="op">=</span> <span class="number">1.0</span> <span class="op">/</span> <span class="ident">z</span>; |
| } |
| |
| <span class="kw">if</span> <span class="ident">hx</span> <span class="op"><</span> <span class="number">0</span> { |
| <span class="kw">if</span> ((<span class="ident">ix</span> <span class="op">-</span> <span class="number">0x3f800000</span>) <span class="op">|</span> <span class="ident">yisint</span>) <span class="op">==</span> <span class="number">0</span> { |
| <span class="ident">z</span> <span class="op">=</span> (<span class="ident">z</span> <span class="op">-</span> <span class="ident">z</span>) <span class="op">/</span> (<span class="ident">z</span> <span class="op">-</span> <span class="ident">z</span>); <span class="comment">/* (-1)**non-int is NaN */</span> |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">yisint</span> <span class="op">==</span> <span class="number">1</span> { |
| <span class="ident">z</span> <span class="op">=</span> <span class="op">-</span><span class="ident">z</span>; <span class="comment">/* (x<0)**odd = -(|x|**odd) */</span> |
| } |
| } |
| <span class="kw">return</span> <span class="ident">z</span>; |
| } |
| |
| <span class="ident">sn</span> <span class="op">=</span> <span class="number">1.0</span>; <span class="comment">/* sign of result */</span> |
| <span class="kw">if</span> <span class="ident">hx</span> <span class="op"><</span> <span class="number">0</span> { |
| <span class="kw">if</span> <span class="ident">yisint</span> <span class="op">==</span> <span class="number">0</span> { |
| <span class="comment">/* (x<0)**(non-int) is NaN */</span> |
| <span class="kw">return</span> (<span class="ident">x</span> <span class="op">-</span> <span class="ident">x</span>) <span class="op">/</span> (<span class="ident">x</span> <span class="op">-</span> <span class="ident">x</span>); |
| } |
| |
| <span class="kw">if</span> <span class="ident">yisint</span> <span class="op">==</span> <span class="number">1</span> { |
| <span class="comment">/* (x<0)**(odd int) */</span> |
| <span class="ident">sn</span> <span class="op">=</span> <span class="op">-</span><span class="number">1.0</span>; |
| } |
| } |
| |
| <span class="comment">/* |y| is HUGE */</span> |
| <span class="kw">if</span> <span class="ident">iy</span> <span class="op">></span> <span class="number">0x4d000000</span> { |
| <span class="comment">/* if |y| > 2**27 */</span> |
| <span class="comment">/* over/underflow if x is not close to one */</span> |
| <span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span> <span class="number">0x3f7ffff8</span> { |
| <span class="kw">return</span> <span class="kw">if</span> <span class="ident">hy</span> <span class="op"><</span> <span class="number">0</span> { |
| <span class="ident">sn</span> <span class="op">*</span> <span class="ident">HUGE</span> <span class="op">*</span> <span class="ident">HUGE</span> |
| } <span class="kw">else</span> { |
| <span class="ident">sn</span> <span class="op">*</span> <span class="ident">TINY</span> <span class="op">*</span> <span class="ident">TINY</span> |
| }; |
| } |
| |
| <span class="kw">if</span> <span class="ident">ix</span> <span class="op">></span> <span class="number">0x3f800007</span> { |
| <span class="kw">return</span> <span class="kw">if</span> <span class="ident">hy</span> <span class="op">></span> <span class="number">0</span> { |
| <span class="ident">sn</span> <span class="op">*</span> <span class="ident">HUGE</span> <span class="op">*</span> <span class="ident">HUGE</span> |
| } <span class="kw">else</span> { |
| <span class="ident">sn</span> <span class="op">*</span> <span class="ident">TINY</span> <span class="op">*</span> <span class="ident">TINY</span> |
| }; |
| } |
| |
| <span class="comment">/* now |1-x| is TINY <= 2**-20, suffice to compute |
| log(x) by x-x^2/2+x^3/3-x^4/4 */</span> |
| <span class="ident">t</span> <span class="op">=</span> <span class="ident">ax</span> <span class="op">-</span> <span class="number">1.</span>; <span class="comment">/* t has 20 trailing zeros */</span> |
| <span class="ident">w</span> <span class="op">=</span> (<span class="ident">t</span> <span class="op">*</span> <span class="ident">t</span>) <span class="op">*</span> (<span class="number">0.5</span> <span class="op">-</span> <span class="ident">t</span> <span class="op">*</span> (<span class="number">0.333333333333</span> <span class="op">-</span> <span class="ident">t</span> <span class="op">*</span> <span class="number">0.25</span>)); |
| <span class="ident">u</span> <span class="op">=</span> <span class="ident">IVLN2_H</span> <span class="op">*</span> <span class="ident">t</span>; <span class="comment">/* IVLN2_H has 16 sig. bits */</span> |
| <span class="ident">v</span> <span class="op">=</span> <span class="ident">t</span> <span class="op">*</span> <span class="ident">IVLN2_L</span> <span class="op">-</span> <span class="ident">w</span> <span class="op">*</span> <span class="ident">IVLN2</span>; |
| <span class="ident">t1</span> <span class="op">=</span> <span class="ident">u</span> <span class="op">+</span> <span class="ident">v</span>; |
| <span class="ident">is</span> <span class="op">=</span> <span class="ident">t1</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">t1</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="number">0xfffff000</span>); |
| <span class="ident">t2</span> <span class="op">=</span> <span class="ident">v</span> <span class="op">-</span> (<span class="ident">t1</span> <span class="op">-</span> <span class="ident">u</span>); |
| } <span class="kw">else</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s2</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s_h</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="ident">s_l</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t_h</span>: <span class="ident">f32</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t_l</span>: <span class="ident">f32</span>; |
| |
| <span class="ident">n</span> <span class="op">=</span> <span class="number">0</span>; |
| <span class="comment">/* take care subnormal number */</span> |
| <span class="kw">if</span> <span class="ident">ix</span> <span class="op"><</span> <span class="number">0x00800000</span> { |
| <span class="ident">ax</span> <span class="kw-2">*</span><span class="op">=</span> <span class="ident">TWO24</span>; |
| <span class="ident">n</span> <span class="op">-</span><span class="op">=</span> <span class="number">24</span>; |
| <span class="ident">ix</span> <span class="op">=</span> <span class="ident">ax</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| } |
| <span class="ident">n</span> <span class="op">+</span><span class="op">=</span> ((<span class="ident">ix</span>) <span class="op">></span><span class="op">></span> <span class="number">23</span>) <span class="op">-</span> <span class="number">0x7f</span>; |
| <span class="ident">j</span> <span class="op">=</span> <span class="ident">ix</span> <span class="op">&</span> <span class="number">0x007fffff</span>; |
| <span class="comment">/* determine interval */</span> |
| <span class="ident">ix</span> <span class="op">=</span> <span class="ident">j</span> <span class="op">|</span> <span class="number">0x3f800000</span>; <span class="comment">/* normalize ix */</span> |
| <span class="kw">if</span> <span class="ident">j</span> <span class="op"><</span><span class="op">=</span> <span class="number">0x1cc471</span> { |
| <span class="comment">/* |x|<sqrt(3/2) */</span> |
| <span class="ident">k</span> <span class="op">=</span> <span class="number">0</span>; |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">j</span> <span class="op"><</span> <span class="number">0x5db3d7</span> { |
| <span class="comment">/* |x|<sqrt(3) */</span> |
| <span class="ident">k</span> <span class="op">=</span> <span class="number">1</span>; |
| } <span class="kw">else</span> { |
| <span class="ident">k</span> <span class="op">=</span> <span class="number">0</span>; |
| <span class="ident">n</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>; |
| <span class="ident">ix</span> <span class="op">-</span><span class="op">=</span> <span class="number">0x00800000</span>; |
| } |
| <span class="ident">ax</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">ix</span> <span class="kw">as</span> <span class="ident">u32</span>); |
| |
| <span class="comment">/* compute s = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */</span> |
| <span class="ident">u</span> <span class="op">=</span> <span class="ident">ax</span> <span class="op">-</span> <span class="ident">BP</span>[<span class="ident">k</span> <span class="kw">as</span> <span class="ident">usize</span>]; <span class="comment">/* bp[0]=1.0, bp[1]=1.5 */</span> |
| <span class="ident">v</span> <span class="op">=</span> <span class="number">1.0</span> <span class="op">/</span> (<span class="ident">ax</span> <span class="op">+</span> <span class="ident">BP</span>[<span class="ident">k</span> <span class="kw">as</span> <span class="ident">usize</span>]); |
| <span class="ident">s</span> <span class="op">=</span> <span class="ident">u</span> <span class="op">*</span> <span class="ident">v</span>; |
| <span class="ident">s_h</span> <span class="op">=</span> <span class="ident">s</span>; |
| <span class="ident">is</span> <span class="op">=</span> <span class="ident">s_h</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">s_h</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="number">0xfffff000</span>); |
| <span class="comment">/* t_h=ax+bp[k] High */</span> |
| <span class="ident">is</span> <span class="op">=</span> (((<span class="ident">ix</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">></span><span class="op">></span> <span class="number">1</span>) <span class="op">&</span> <span class="number">0xfffff000</span>) <span class="op">|</span> <span class="number">0x20000000</span>) <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">t_h</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">+</span> <span class="number">0x00400000</span> <span class="op">+</span> ((<span class="ident">k</span> <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><</span><span class="op"><</span> <span class="number">21</span>)); |
| <span class="ident">t_l</span> <span class="op">=</span> <span class="ident">ax</span> <span class="op">-</span> (<span class="ident">t_h</span> <span class="op">-</span> <span class="ident">BP</span>[<span class="ident">k</span> <span class="kw">as</span> <span class="ident">usize</span>]); |
| <span class="ident">s_l</span> <span class="op">=</span> <span class="ident">v</span> <span class="op">*</span> ((<span class="ident">u</span> <span class="op">-</span> <span class="ident">s_h</span> <span class="op">*</span> <span class="ident">t_h</span>) <span class="op">-</span> <span class="ident">s_h</span> <span class="op">*</span> <span class="ident">t_l</span>); |
| <span class="comment">/* compute log(ax) */</span> |
| <span class="ident">s2</span> <span class="op">=</span> <span class="ident">s</span> <span class="op">*</span> <span class="ident">s</span>; |
| <span class="ident">r</span> <span class="op">=</span> <span class="ident">s2</span> <span class="op">*</span> <span class="ident">s2</span> <span class="op">*</span> (<span class="ident">L1</span> <span class="op">+</span> <span class="ident">s2</span> <span class="op">*</span> (<span class="ident">L2</span> <span class="op">+</span> <span class="ident">s2</span> <span class="op">*</span> (<span class="ident">L3</span> <span class="op">+</span> <span class="ident">s2</span> <span class="op">*</span> (<span class="ident">L4</span> <span class="op">+</span> <span class="ident">s2</span> <span class="op">*</span> (<span class="ident">L5</span> <span class="op">+</span> <span class="ident">s2</span> <span class="op">*</span> <span class="ident">L6</span>))))); |
| <span class="ident">r</span> <span class="op">+</span><span class="op">=</span> <span class="ident">s_l</span> <span class="op">*</span> (<span class="ident">s_h</span> <span class="op">+</span> <span class="ident">s</span>); |
| <span class="ident">s2</span> <span class="op">=</span> <span class="ident">s_h</span> <span class="op">*</span> <span class="ident">s_h</span>; |
| <span class="ident">t_h</span> <span class="op">=</span> <span class="number">3.0</span> <span class="op">+</span> <span class="ident">s2</span> <span class="op">+</span> <span class="ident">r</span>; |
| <span class="ident">is</span> <span class="op">=</span> <span class="ident">t_h</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">t_h</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="number">0xfffff000</span>); |
| <span class="ident">t_l</span> <span class="op">=</span> <span class="ident">r</span> <span class="op">-</span> ((<span class="ident">t_h</span> <span class="op">-</span> <span class="number">3.0</span>) <span class="op">-</span> <span class="ident">s2</span>); |
| <span class="comment">/* u+v = s*(1+...) */</span> |
| <span class="ident">u</span> <span class="op">=</span> <span class="ident">s_h</span> <span class="op">*</span> <span class="ident">t_h</span>; |
| <span class="ident">v</span> <span class="op">=</span> <span class="ident">s_l</span> <span class="op">*</span> <span class="ident">t_h</span> <span class="op">+</span> <span class="ident">t_l</span> <span class="op">*</span> <span class="ident">s</span>; |
| <span class="comment">/* 2/(3log2)*(s+...) */</span> |
| <span class="ident">p_h</span> <span class="op">=</span> <span class="ident">u</span> <span class="op">+</span> <span class="ident">v</span>; |
| <span class="ident">is</span> <span class="op">=</span> <span class="ident">p_h</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">p_h</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="number">0xfffff000</span>); |
| <span class="ident">p_l</span> <span class="op">=</span> <span class="ident">v</span> <span class="op">-</span> (<span class="ident">p_h</span> <span class="op">-</span> <span class="ident">u</span>); |
| <span class="ident">z_h</span> <span class="op">=</span> <span class="ident">CP_H</span> <span class="op">*</span> <span class="ident">p_h</span>; <span class="comment">/* cp_h+cp_l = 2/(3*log2) */</span> |
| <span class="ident">z_l</span> <span class="op">=</span> <span class="ident">CP_L</span> <span class="op">*</span> <span class="ident">p_h</span> <span class="op">+</span> <span class="ident">p_l</span> <span class="op">*</span> <span class="ident">CP</span> <span class="op">+</span> <span class="ident">DP_L</span>[<span class="ident">k</span> <span class="kw">as</span> <span class="ident">usize</span>]; |
| <span class="comment">/* log2(ax) = (s+..)*2/(3*log2) = n + dp_h + z_h + z_l */</span> |
| <span class="ident">t</span> <span class="op">=</span> <span class="ident">n</span> <span class="kw">as</span> <span class="ident">f32</span>; |
| <span class="ident">t1</span> <span class="op">=</span> ((<span class="ident">z_h</span> <span class="op">+</span> <span class="ident">z_l</span>) <span class="op">+</span> <span class="ident">DP_H</span>[<span class="ident">k</span> <span class="kw">as</span> <span class="ident">usize</span>]) <span class="op">+</span> <span class="ident">t</span>; |
| <span class="ident">is</span> <span class="op">=</span> <span class="ident">t1</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">t1</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="number">0xfffff000</span>); |
| <span class="ident">t2</span> <span class="op">=</span> <span class="ident">z_l</span> <span class="op">-</span> (((<span class="ident">t1</span> <span class="op">-</span> <span class="ident">t</span>) <span class="op">-</span> <span class="ident">DP_H</span>[<span class="ident">k</span> <span class="kw">as</span> <span class="ident">usize</span>]) <span class="op">-</span> <span class="ident">z_h</span>); |
| }; |
| |
| <span class="comment">/* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */</span> |
| <span class="ident">is</span> <span class="op">=</span> <span class="ident">y</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">y1</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="number">0xfffff000</span>); |
| <span class="ident">p_l</span> <span class="op">=</span> (<span class="ident">y</span> <span class="op">-</span> <span class="ident">y1</span>) <span class="op">*</span> <span class="ident">t1</span> <span class="op">+</span> <span class="ident">y</span> <span class="op">*</span> <span class="ident">t2</span>; |
| <span class="ident">p_h</span> <span class="op">=</span> <span class="ident">y1</span> <span class="op">*</span> <span class="ident">t1</span>; |
| <span class="ident">z</span> <span class="op">=</span> <span class="ident">p_l</span> <span class="op">+</span> <span class="ident">p_h</span>; |
| <span class="ident">j</span> <span class="op">=</span> <span class="ident">z</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="kw">if</span> <span class="ident">j</span> <span class="op">></span> <span class="number">0x43000000</span> { |
| <span class="comment">/* if z > 128 */</span> |
| <span class="kw">return</span> <span class="ident">sn</span> <span class="op">*</span> <span class="ident">HUGE</span> <span class="op">*</span> <span class="ident">HUGE</span>; <span class="comment">/* overflow */</span> |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">j</span> <span class="op">==</span> <span class="number">0x43000000</span> { |
| <span class="comment">/* if z == 128 */</span> |
| <span class="kw">if</span> <span class="ident">p_l</span> <span class="op">+</span> <span class="ident">OVT</span> <span class="op">></span> <span class="ident">z</span> <span class="op">-</span> <span class="ident">p_h</span> { |
| <span class="kw">return</span> <span class="ident">sn</span> <span class="op">*</span> <span class="ident">HUGE</span> <span class="op">*</span> <span class="ident">HUGE</span>; <span class="comment">/* overflow */</span> |
| } |
| } <span class="kw">else</span> <span class="kw">if</span> (<span class="ident">j</span> <span class="op">&</span> <span class="number">0x7fffffff</span>) <span class="op">></span> <span class="number">0x43160000</span> { |
| <span class="comment">/* z < -150 */</span> |
| <span class="comment">// FIXME: check should be (uint32_t)j > 0xc3160000</span> |
| <span class="kw">return</span> <span class="ident">sn</span> <span class="op">*</span> <span class="ident">TINY</span> <span class="op">*</span> <span class="ident">TINY</span>; <span class="comment">/* underflow */</span> |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">j</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">==</span> <span class="number">0xc3160000</span> |
| <span class="comment">/* z == -150 */</span> |
| <span class="op">&&</span> <span class="ident">p_l</span> <span class="op"><</span><span class="op">=</span> <span class="ident">z</span> <span class="op">-</span> <span class="ident">p_h</span> |
| { |
| <span class="kw">return</span> <span class="ident">sn</span> <span class="op">*</span> <span class="ident">TINY</span> <span class="op">*</span> <span class="ident">TINY</span>; <span class="comment">/* underflow */</span> |
| } |
| |
| <span class="comment">/* |
| * compute 2**(p_h+p_l) |
| */</span> |
| <span class="ident">i</span> <span class="op">=</span> <span class="ident">j</span> <span class="op">&</span> <span class="number">0x7fffffff</span>; |
| <span class="ident">k</span> <span class="op">=</span> (<span class="ident">i</span> <span class="op">></span><span class="op">></span> <span class="number">23</span>) <span class="op">-</span> <span class="number">0x7f</span>; |
| <span class="ident">n</span> <span class="op">=</span> <span class="number">0</span>; |
| <span class="kw">if</span> <span class="ident">i</span> <span class="op">></span> <span class="number">0x3f000000</span> { |
| <span class="comment">/* if |z| > 0.5, set n = [z+0.5] */</span> |
| <span class="ident">n</span> <span class="op">=</span> <span class="ident">j</span> <span class="op">+</span> (<span class="number">0x00800000</span> <span class="op">></span><span class="op">></span> (<span class="ident">k</span> <span class="op">+</span> <span class="number">1</span>)); |
| <span class="ident">k</span> <span class="op">=</span> ((<span class="ident">n</span> <span class="op">&</span> <span class="number">0x7fffffff</span>) <span class="op">></span><span class="op">></span> <span class="number">23</span>) <span class="op">-</span> <span class="number">0x7f</span>; <span class="comment">/* new k for n */</span> |
| <span class="ident">t</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">n</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="op">!</span>(<span class="number">0x007fffff</span> <span class="op">></span><span class="op">></span> <span class="ident">k</span>)); |
| <span class="ident">n</span> <span class="op">=</span> ((<span class="ident">n</span> <span class="op">&</span> <span class="number">0x007fffff</span>) <span class="op">|</span> <span class="number">0x00800000</span>) <span class="op">></span><span class="op">></span> (<span class="number">23</span> <span class="op">-</span> <span class="ident">k</span>); |
| <span class="kw">if</span> <span class="ident">j</span> <span class="op"><</span> <span class="number">0</span> { |
| <span class="ident">n</span> <span class="op">=</span> <span class="op">-</span><span class="ident">n</span>; |
| } |
| <span class="ident">p_h</span> <span class="op">-</span><span class="op">=</span> <span class="ident">t</span>; |
| } |
| <span class="ident">t</span> <span class="op">=</span> <span class="ident">p_l</span> <span class="op">+</span> <span class="ident">p_h</span>; |
| <span class="ident">is</span> <span class="op">=</span> <span class="ident">t</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">t</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">is</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&</span> <span class="number">0xffff8000</span>); |
| <span class="ident">u</span> <span class="op">=</span> <span class="ident">t</span> <span class="op">*</span> <span class="ident">LG2_H</span>; |
| <span class="ident">v</span> <span class="op">=</span> (<span class="ident">p_l</span> <span class="op">-</span> (<span class="ident">t</span> <span class="op">-</span> <span class="ident">p_h</span>)) <span class="op">*</span> <span class="ident">LG2</span> <span class="op">+</span> <span class="ident">t</span> <span class="op">*</span> <span class="ident">LG2_L</span>; |
| <span class="ident">z</span> <span class="op">=</span> <span class="ident">u</span> <span class="op">+</span> <span class="ident">v</span>; |
| <span class="ident">w</span> <span class="op">=</span> <span class="ident">v</span> <span class="op">-</span> (<span class="ident">z</span> <span class="op">-</span> <span class="ident">u</span>); |
| <span class="ident">t</span> <span class="op">=</span> <span class="ident">z</span> <span class="op">*</span> <span class="ident">z</span>; |
| <span class="ident">t1</span> <span class="op">=</span> <span class="ident">z</span> <span class="op">-</span> <span class="ident">t</span> <span class="op">*</span> (<span class="ident">P1</span> <span class="op">+</span> <span class="ident">t</span> <span class="op">*</span> (<span class="ident">P2</span> <span class="op">+</span> <span class="ident">t</span> <span class="op">*</span> (<span class="ident">P3</span> <span class="op">+</span> <span class="ident">t</span> <span class="op">*</span> (<span class="ident">P4</span> <span class="op">+</span> <span class="ident">t</span> <span class="op">*</span> <span class="ident">P5</span>)))); |
| <span class="ident">r</span> <span class="op">=</span> (<span class="ident">z</span> <span class="op">*</span> <span class="ident">t1</span>) <span class="op">/</span> (<span class="ident">t1</span> <span class="op">-</span> <span class="number">2.0</span>) <span class="op">-</span> (<span class="ident">w</span> <span class="op">+</span> <span class="ident">z</span> <span class="op">*</span> <span class="ident">w</span>); |
| <span class="ident">z</span> <span class="op">=</span> <span class="number">1.0</span> <span class="op">-</span> (<span class="ident">r</span> <span class="op">-</span> <span class="ident">z</span>); |
| <span class="ident">j</span> <span class="op">=</span> <span class="ident">z</span>.<span class="ident">to_bits</span>() <span class="kw">as</span> <span class="ident">i32</span>; |
| <span class="ident">j</span> <span class="op">+</span><span class="op">=</span> <span class="ident">n</span> <span class="op"><</span><span class="op"><</span> <span class="number">23</span>; |
| <span class="kw">if</span> (<span class="ident">j</span> <span class="op">></span><span class="op">></span> <span class="number">23</span>) <span class="op"><</span><span class="op">=</span> <span class="number">0</span> { |
| <span class="comment">/* subnormal output */</span> |
| <span class="ident">z</span> <span class="op">=</span> <span class="ident">scalbnf</span>(<span class="ident">z</span>, <span class="ident">n</span>); |
| } <span class="kw">else</span> { |
| <span class="ident">z</span> <span class="op">=</span> <span class="ident">f32::from_bits</span>(<span class="ident">j</span> <span class="kw">as</span> <span class="ident">u32</span>); |
| } |
| <span class="ident">sn</span> <span class="op">*</span> <span class="ident">z</span> |
| } |
| </code></pre></div> |
| </section><section id="search" class="content hidden"></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="1.60.0-nightly (1bd4fdc94 2022-01-12)" ></div> |
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