| /* origin: FreeBSD /usr/src/lib/msun/src/k_cosf.c */ |
| /* |
| * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
| * Debugged and optimized by Bruce D. Evans. |
| */ |
| /* |
| * ==================================================== |
| * 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. |
| * ==================================================== |
| */ |
| |
| /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */ |
| const C0: f64 = -0.499999997251031003120; /* -0x1ffffffd0c5e81.0p-54 */ |
| const C1: f64 = 0.0416666233237390631894; /* 0x155553e1053a42.0p-57 */ |
| const C2: f64 = -0.00138867637746099294692; /* -0x16c087e80f1e27.0p-62 */ |
| const C3: f64 = 0.0000243904487962774090654; /* 0x199342e0ee5069.0p-68 */ |
| |
| #[inline] |
| pub fn k_cosf(x: f64) -> f32 { |
| let z = x * x; |
| let w = z * z; |
| let r = C2 + z * C3; |
| (((1.0 + z * C0) + w * C1) + (w * z) * r) as f32 |
| } |
