1*f504f610SAugustin Cavalier /* origin: FreeBSD /usr/src/lib/msun/src/k_cosf.c */
2*f504f610SAugustin Cavalier /*
3*f504f610SAugustin Cavalier * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
4*f504f610SAugustin Cavalier * Debugged and optimized by Bruce D. Evans.
5*f504f610SAugustin Cavalier */
6*f504f610SAugustin Cavalier /*
7*f504f610SAugustin Cavalier * ====================================================
8*f504f610SAugustin Cavalier * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9*f504f610SAugustin Cavalier *
10*f504f610SAugustin Cavalier * Developed at SunPro, a Sun Microsystems, Inc. business.
11*f504f610SAugustin Cavalier * Permission to use, copy, modify, and distribute this
12*f504f610SAugustin Cavalier * software is freely granted, provided that this notice
13*f504f610SAugustin Cavalier * is preserved.
14*f504f610SAugustin Cavalier * ====================================================
15*f504f610SAugustin Cavalier */
16*f504f610SAugustin Cavalier
17*f504f610SAugustin Cavalier #include "libm.h"
18*f504f610SAugustin Cavalier
19*f504f610SAugustin Cavalier /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
20*f504f610SAugustin Cavalier static const double
21*f504f610SAugustin Cavalier C0 = -0x1ffffffd0c5e81.0p-54, /* -0.499999997251031003120 */
22*f504f610SAugustin Cavalier C1 = 0x155553e1053a42.0p-57, /* 0.0416666233237390631894 */
23*f504f610SAugustin Cavalier C2 = -0x16c087e80f1e27.0p-62, /* -0.00138867637746099294692 */
24*f504f610SAugustin Cavalier C3 = 0x199342e0ee5069.0p-68; /* 0.0000243904487962774090654 */
25*f504f610SAugustin Cavalier
__cosdf(double x)26*f504f610SAugustin Cavalier float __cosdf(double x)
27*f504f610SAugustin Cavalier {
28*f504f610SAugustin Cavalier double_t r, w, z;
29*f504f610SAugustin Cavalier
30*f504f610SAugustin Cavalier /* Try to optimize for parallel evaluation as in __tandf.c. */
31*f504f610SAugustin Cavalier z = x*x;
32*f504f610SAugustin Cavalier w = z*z;
33*f504f610SAugustin Cavalier r = C2+z*C3;
34*f504f610SAugustin Cavalier return ((1.0+z*C0) + w*C1) + (w*z)*r;
35*f504f610SAugustin Cavalier }
36