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