xref: /freebsd/lib/msun/src/k_sinf.c (revision 8fc257994d0ce2396196d7a06d50d20c8015f4b7)
1 /* k_sinf.c -- float version of k_sin.c
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  * 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_SINDF
18 #include <sys/cdefs.h>
19 __FBSDID("$FreeBSD$");
20 #endif
21 
22 #include "math.h"
23 #include "math_private.h"
24 
25 /* |sin(x)/x - s(x)| < 2**-37.5 (~[-4.89e-12, 4.824e-12]). */
26 static const double
27 S1 = -0x15555554cbac77.0p-55,	/* -0.166666666416265235595 */
28 S2 =  0x111110896efbb2.0p-59,	/*  0.0083333293858894631756 */
29 S3 = -0x1a00f9e2cae774.0p-65,	/* -0.000198393348360966317347 */
30 S4 =  0x16cd878c3b46a7.0p-71;	/*  0.0000027183114939898219064 */
31 
32 #ifndef INLINE_KERNEL_SINDF
33 extern
34 #endif
35 __inline float
36 __kernel_sindf(double x)
37 {
38 	double r, s, w, z;
39 
40 	/* Try to optimize for parallel evaluation as in k_tanf.c. */
41 	z = x*x;
42 	w = z*z;
43 	r = S3+z*S4;
44 	s = z*x;
45 	return (x + s*(S1+z*S2)) + s*w*r;
46 }
47