From 9835e2ae736235810b4ea1c162ca5e65c547e770 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 04:49:50 +0200 Subject: Merging upstream version 1.71.1+dfsg1. Signed-off-by: Daniel Baumann --- vendor/libm-0.1.4/src/math/log10f.rs | 92 ++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 vendor/libm-0.1.4/src/math/log10f.rs (limited to 'vendor/libm-0.1.4/src/math/log10f.rs') diff --git a/vendor/libm-0.1.4/src/math/log10f.rs b/vendor/libm-0.1.4/src/math/log10f.rs new file mode 100644 index 000000000..9845cda5d --- /dev/null +++ b/vendor/libm-0.1.4/src/math/log10f.rs @@ -0,0 +1,92 @@ +/* origin: FreeBSD /usr/src/lib/msun/src/e_log10f.c */ +/* + * ==================================================== + * 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. + * ==================================================== + */ +/* + * See comments in log10.c. + */ + +use core::f32; + +const IVLN10HI: f32 = 4.3432617188e-01; /* 0x3ede6000 */ +const IVLN10LO: f32 = -3.1689971365e-05; /* 0xb804ead9 */ +const LOG10_2HI: f32 = 3.0102920532e-01; /* 0x3e9a2080 */ +const LOG10_2LO: f32 = 7.9034151668e-07; /* 0x355427db */ +/* |(log(1+s)-log(1-s))/s - Lg(s)| < 2**-34.24 (~[-4.95e-11, 4.97e-11]). */ +const LG1: f32 = 0.66666662693; /* 0xaaaaaa.0p-24 */ +const LG2: f32 = 0.40000972152; /* 0xccce13.0p-25 */ +const LG3: f32 = 0.28498786688; /* 0x91e9ee.0p-25 */ +const LG4: f32 = 0.24279078841; /* 0xf89e26.0p-26 */ + +#[inline] +#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] +pub fn log10f(mut x: f32) -> f32 { + let x1p25f = f32::from_bits(0x4c000000); // 0x1p25f === 2 ^ 25 + + let mut ui: u32 = x.to_bits(); + let hfsq: f32; + let f: f32; + let s: f32; + let z: f32; + let r: f32; + let w: f32; + let t1: f32; + let t2: f32; + let dk: f32; + let mut hi: f32; + let lo: f32; + let mut ix: u32; + let mut k: i32; + + ix = ui; + k = 0; + if ix < 0x00800000 || (ix >> 31) > 0 { + /* x < 2**-126 */ + if ix << 1 == 0 { + return -1. / (x * x); /* log(+-0)=-inf */ + } + if (ix >> 31) > 0 { + return (x - x) / 0.0; /* log(-#) = NaN */ + } + /* subnormal number, scale up x */ + k -= 25; + x *= x1p25f; + ui = x.to_bits(); + ix = ui; + } else if ix >= 0x7f800000 { + return x; + } else if ix == 0x3f800000 { + return 0.; + } + + /* reduce x into [sqrt(2)/2, sqrt(2)] */ + ix += 0x3f800000 - 0x3f3504f3; + k += (ix >> 23) as i32 - 0x7f; + ix = (ix & 0x007fffff) + 0x3f3504f3; + ui = ix; + x = f32::from_bits(ui); + + f = x - 1.0; + s = f / (2.0 + f); + z = s * s; + w = z * z; + t1 = w * (LG2 + w * LG4); + t2 = z * (LG1 + w * LG3); + r = t2 + t1; + hfsq = 0.5 * f * f; + + hi = f - hfsq; + ui = hi.to_bits(); + ui &= 0xfffff000; + hi = f32::from_bits(ui); + lo = f - hi - hfsq + s * (hfsq + r); + dk = k as f32; + dk * LOG10_2LO + (lo + hi) * IVLN10LO + lo * IVLN10HI + hi * IVLN10HI + dk * LOG10_2HI +} -- cgit v1.2.3