1 /* origin: FreeBSD /usr/src/lib/msun/src/k_cosf.c */
2 /*
3 * Conversion to float by Ian Lance Taylor, Cygnus Support, [email protected].
4 * Debugged and optimized by Bruce D. Evans.
5 */
6 /*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 *
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
13 * is preserved.
14 * ====================================================
15 */
16
17 /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
18 const C0: f64 = -0.499999997251031003120; /* -0x1ffffffd0c5e81.0p-54 */
19 const C1: f64 = 0.0416666233237390631894; /* 0x155553e1053a42.0p-57 */
20 const C2: f64 = -0.00138867637746099294692; /* -0x16c087e80f1e27.0p-62 */
21 const C3: f64 = 0.0000243904487962774090654; /* 0x199342e0ee5069.0p-68 */
22
23 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
k_cosf(x: f64) -> f3224 pub(crate) fn k_cosf(x: f64) -> f32 {
25 let z = x * x;
26 let w = z * z;
27 let r = C2 + z * C3;
28 (((1.0 + z * C0) + w * C1) + (w * z) * r) as f32
29 }
30