1 /* k_cosf.c -- float version of k_cos.c
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  * Debugged and optimized by Bruce D. Evans.
4  */
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 #ifndef INLINE_KERNEL_COSDF
18 #include <sys/cdefs.h>
19 __FBSDID("$FreeBSD$");
20 #endif
21 
22 #include "math.h"
23 #include "math_private.h"
24 
25 /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
26 static const double
27 one =  1.0,
28 C0  = -0x1ffffffd0c5e81.0p-54,  /* -0.499999997251031003120 */
29 C1  =  0x155553e1053a42.0p-57,  /*  0.0416666233237390631894 */
30 C2  = -0x16c087e80f1e27.0p-62,  /* -0.00138867637746099294692 */
31 C3  =  0x199342e0ee5069.0p-68;  /*  0.0000243904487962774090654 */
32 
33 #ifdef INLINE_KERNEL_COSDF
34 static __inline
35 #endif
36 float
__kernel_cosdf(double x)37 __kernel_cosdf(double x)
38 {
39     double r, w, z;
40 
41     /* Try to optimize for parallel evaluation as in k_tanf.c. */
42     z = x*x;
43     w = z*z;
44     r = C2+z*C3;
45     return ((one+z*C0) + w*C1) + (w*z)*r;
46 }
47