xref: /freebsd/lib/msun/src/k_sincos.h (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
1 /*-
2  * ====================================================
3  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4  *
5  * Developed at SunSoft, a Sun Microsystems, Inc. business.
6  * Permission to use, copy, modify, and distribute this
7  * software is freely granted, provided that this notice
8  * is preserved.
9  * ====================================================
10  *
11  * k_sin.c and k_cos.c merged by Steven G. Kargl.
12  */
13 
14 static const double
15 S1  = -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */
16 S2  =  8.33333333332248946124e-03, /* 0x3F811111, 0x1110F8A6 */
17 S3  = -1.98412698298579493134e-04, /* 0xBF2A01A0, 0x19C161D5 */
18 S4  =  2.75573137070700676789e-06, /* 0x3EC71DE3, 0x57B1FE7D */
19 S5  = -2.50507602534068634195e-08, /* 0xBE5AE5E6, 0x8A2B9CEB */
20 S6  =  1.58969099521155010221e-10; /* 0x3DE5D93A, 0x5ACFD57C */
21 
22 static const double
23 C1  =  4.16666666666666019037e-02, /* 0x3FA55555, 0x5555554C */
24 C2  = -1.38888888888741095749e-03, /* 0xBF56C16C, 0x16C15177 */
25 C3  =  2.48015872894767294178e-05, /* 0x3EFA01A0, 0x19CB1590 */
26 C4  = -2.75573143513906633035e-07, /* 0xBE927E4F, 0x809C52AD */
27 C5  =  2.08757232129817482790e-09, /* 0x3E21EE9E, 0xBDB4B1C4 */
28 C6  = -1.13596475577881948265e-11; /* 0xBDA8FAE9, 0xBE8838D4 */
29 
30 static inline void
31 __kernel_sincos(double x, double y, int iy, double *sn, double *cs)
32 {
33 	double hz, r, v, w, z;
34 
35 	z = x * x;
36 	w = z * z;
37 	r = S2 + z * (S3 + z * S4) + z * w * (S5 + z * S6);
38 	v = z * x;
39 
40 	if (iy == 0)
41 		*sn = x + v * (S1 + z * r);
42 	else
43 		*sn = x - ((z * (y / 2 - v * r) - y) - v * S1);
44 
45 	r = z * (C1 + z * (C2 + z * C3)) + w * w * (C4 + z * (C5 + z * C6));
46 	hz = z / 2;
47 	w = 1 - hz;
48 	*cs = w + (((1 - w) - hz) + (z * r - x * y));
49 }
50