k_sinf.c revision 152341 
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 lint
18static char rcsid[] = "$FreeBSD: head/lib/msun/src/k_sinf.c 152341 2005-11-12 19:56:35Z bde $";
19#endif
20
21#include "math.h"
22#include "math_private.h"
23
24/* |sin(x)/x - s(x)| < 2**-32.5 (~[-1.57e-10, 1.572e-10]). */
25static const float
26half = 0.5,
27S1  = -0xaaaaab.0p-26,		/* -0.16666667163 */
28S2  =  0x8888bb.0p-30,		/*  0.0083333803341 */
29S3  = -0xd02de1.0p-36,		/* -0.00019853517006 */
30S4  =  0xbe6dbe.0p-42;		/*  0.0000028376084629 */
31
32float
33__kernel_sinf(float x, float y, int iy)
34{
35	float z,r,v;
36
37	z	=  x*x;
38	v	=  z*x;
39	r	=  S2+z*(S3+z*S4);
40	if(iy==0) return x+v*(S1+z*r);
41	else      return x-((z*(half*y-v*r)-y)-v*S1);
42}
43