29 lines
1.1 KiB
Rust
29 lines
1.1 KiB
Rust
/* origin: FreeBSD /usr/src/lib/msun/src/k_cosf.c */
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/*
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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* Debugged and optimized by Bruce D. Evans.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
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const C0: f64 = -0.499999997251031003120; /* -0x1ffffffd0c5e81.0p-54 */
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const C1: f64 = 0.0416666233237390631894; /* 0x155553e1053a42.0p-57 */
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const C2: f64 = -0.00138867637746099294692; /* -0x16c087e80f1e27.0p-62 */
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const C3: f64 = 0.0000243904487962774090654; /* 0x199342e0ee5069.0p-68 */
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#[cfg_attr(assert_no_panic, no_panic::no_panic)]
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pub(crate) fn k_cosf(x: f64) -> f32 {
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let z = x * x;
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let w = z * z;
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let r = C2 + z * C3;
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(((1.0 + z * C0) + w * C1) + (w * z) * r) as f32
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}
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