xref: /freebsd/lib/msun/src/k_sincos.h (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
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 #include <sys/cdefs.h>
15 __FBSDID("$FreeBSD$");
16 
17 static const double
18 S1  = -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */
19 S2  =  8.33333333332248946124e-03, /* 0x3F811111, 0x1110F8A6 */
20 S3  = -1.98412698298579493134e-04, /* 0xBF2A01A0, 0x19C161D5 */
21 S4  =  2.75573137070700676789e-06, /* 0x3EC71DE3, 0x57B1FE7D */
22 S5  = -2.50507602534068634195e-08, /* 0xBE5AE5E6, 0x8A2B9CEB */
23 S6  =  1.58969099521155010221e-10; /* 0x3DE5D93A, 0x5ACFD57C */
24 
25 static const double
26 C1  =  4.16666666666666019037e-02, /* 0x3FA55555, 0x5555554C */
27 C2  = -1.38888888888741095749e-03, /* 0xBF56C16C, 0x16C15177 */
28 C3  =  2.48015872894767294178e-05, /* 0x3EFA01A0, 0x19CB1590 */
29 C4  = -2.75573143513906633035e-07, /* 0xBE927E4F, 0x809C52AD */
30 C5  =  2.08757232129817482790e-09, /* 0x3E21EE9E, 0xBDB4B1C4 */
31 C6  = -1.13596475577881948265e-11; /* 0xBDA8FAE9, 0xBE8838D4 */
32 
33 static inline void
34 __kernel_sincos(double x, double y, int iy, double *sn, double *cs)
35 {
36 	double hz, r, v, w, z;
37 
38 	z = x * x;
39 	w = z * z;
40 	r = S2 + z * (S3 + z * S4) + z * w * (S5 + z * S6);
41 	v = z * x;
42 
43 	if (iy == 0)
44 		*sn = x + v * (S1 + z * r);
45 	else
46 		*sn = x - ((z * (y / 2 - v * r) - y) - v * S1);
47 
48 	r = z * (C1 + z * (C2 + z * C3)) + w * w * (C4 + z * (C5 + z * C6));
49 	hz = z / 2;
50 	w = 1 - hz;
51 	*cs = w + (((1 - w) - hz) + (z * r - x * y));
52 }
53