1/* origin: FreeBSD /usr/src/lib/msun/src/k_cosf.c */
2/*
3 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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#include "libm.h"
18
19/* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
20static const double
21C0 = -0x1ffffffd0c5e81.0p-54, /* -0.499999997251031003120 */
22C1 = 0x155553e1053a42.0p-57, /* 0.0416666233237390631894 */
23C2 = -0x16c087e80f1e27.0p-62, /* -0.00138867637746099294692 */
24C3 = 0x199342e0ee5069.0p-68; /* 0.0000243904487962774090654 */
25
26float __cosdf(double x)
27{
28 double_t r, w, z;
29
30 /* Try to optimize for parallel evaluation as in __tandf.c. */
31 z = x*x;
32 w = z*z;
33 r = C2+z*C3;
34 return ((1.0+z*C0) + w*C1) + (w*z)*r;
35}