1 /* kf_cos.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 #include "fdlibm.h"
17 
18 #ifdef __STDC__
19 static const float
20 #else
21 static float
22 #endif
23 one =  1.0000000000e+00, /* 0x3f800000 */
24 C1  =  4.1666667908e-02, /* 0x3d2aaaab */
25 C2  = -1.3888889225e-03, /* 0xbab60b61 */
26 C3  =  2.4801587642e-05, /* 0x37d00d01 */
27 C4  = -2.7557314297e-07, /* 0xb493f27c */
28 C5  =  2.0875723372e-09, /* 0x310f74f6 */
29 C6  = -1.1359647598e-11; /* 0xad47d74e */
30 
31 #ifdef __STDC__
__kernel_cosf(float x,float y)32 	float __kernel_cosf(float x, float y)
33 #else
34 	float __kernel_cosf(x, y)
35 	float x,y;
36 #endif
37 {
38 	float a,hz,z,r,qx;
39 	__int32_t ix;
40 	GET_FLOAT_WORD(ix,x);
41 	ix &= 0x7fffffff;			/* ix = |x|'s high word*/
42 	if(ix<0x32000000) {			/* if x < 2**27 */
43 	    if(((int)x)==0) return one;		/* generate inexact */
44 	}
45 	z  = x*x;
46 	r  = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
47 	if(ix < 0x3e99999a) 			/* if |x| < 0.3 */
48 	    return one - ((float)0.5*z - (z*r - x*y));
49 	else {
50 	    if(ix > 0x3f480000) {		/* x > 0.78125 */
51 		qx = (float)0.28125;
52 	    } else {
53 	        SET_FLOAT_WORD(qx,ix-0x01000000);	/* x/4 */
54 	    }
55 	    hz = (float)0.5*z-qx;
56 	    a  = one-qx;
57 	    return a - (hz - (z*r-x*y));
58 	}
59 }
60