k_cosf.c revision 2116 
1/* k_cosf.c -- float version of k_cos.c
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
4
5/*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
14 */
15
16#ifndef lint
17static char rcsid[] = "$Id: k_cosf.c,v 1.2 1994/08/18 23:06:10 jtc Exp $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23#ifdef __STDC__
24static const float
25#else
26static float
27#endif
28one =  1.0000000000e+00, /* 0x3f800000 */
29C1  =  4.1666667908e-02, /* 0x3d2aaaab */
30C2  = -1.3888889225e-03, /* 0xbab60b61 */
31C3  =  2.4801587642e-05, /* 0x37d00d01 */
32C4  = -2.7557314297e-07, /* 0xb493f27c */
33C5  =  2.0875723372e-09, /* 0x310f74f6 */
34C6  = -1.1359647598e-11; /* 0xad47d74e */
35
36#ifdef __STDC__
37	float __kernel_cosf(float x, float y)
38#else
39	float __kernel_cosf(x, y)
40	float x,y;
41#endif
42{
43	float a,hz,z,r,qx;
44	int32_t ix;
45	GET_FLOAT_WORD(ix,x);
46	ix &= 0x7fffffff;			/* ix = |x|'s high word*/
47	if(ix<0x32000000) {			/* if x < 2**27 */
48	    if(((int)x)==0) return one;		/* generate inexact */
49	}
50	z  = x*x;
51	r  = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
52	if(ix < 0x3e99999a) 			/* if |x| < 0.3 */
53	    return one - ((float)0.5*z - (z*r - x*y));
54	else {
55	    if(ix > 0x3f480000) {		/* x > 0.78125 */
56		qx = (float)0.28125;
57	    } else {
58	        SET_FLOAT_WORD(qx,ix-0x01000000);	/* x/4 */
59	    }
60	    hz = (float)0.5*z-qx;
61	    a  = one-qx;
62	    return a - (hz - (z*r-x*y));
63	}
64}
65