/*-
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunSoft, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 *
 * k_sin.c and k_cos.c merged by Steven G. Kargl.
 */

#include <sys/cdefs.h>
#if 0
__FBSDID("$FreeBSD: head/lib/msun/src/k_sincos.h 319047 2017-05-28 06:13:38Z mmel $");
#endif
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: k_sincos.h,v 1.2 2022/08/29 01:48:34 riastradh Exp $");
#endif

static const double
S1  = -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */
S2  =  8.33333333332248946124e-03, /* 0x3F811111, 0x1110F8A6 */
S3  = -1.98412698298579493134e-04, /* 0xBF2A01A0, 0x19C161D5 */
S4  =  2.75573137070700676789e-06, /* 0x3EC71DE3, 0x57B1FE7D */
S5  = -2.50507602534068634195e-08, /* 0xBE5AE5E6, 0x8A2B9CEB */
S6  =  1.58969099521155010221e-10; /* 0x3DE5D93A, 0x5ACFD57C */

static const double
C1  =  4.16666666666666019037e-02, /* 0x3FA55555, 0x5555554C */
C2  = -1.38888888888741095749e-03, /* 0xBF56C16C, 0x16C15177 */
C3  =  2.48015872894767294178e-05, /* 0x3EFA01A0, 0x19CB1590 */
C4  = -2.75573143513906633035e-07, /* 0xBE927E4F, 0x809C52AD */
C5  =  2.08757232129817482790e-09, /* 0x3E21EE9E, 0xBDB4B1C4 */
C6  = -1.13596475577881948265e-11; /* 0xBDA8FAE9, 0xBE8838D4 */

static inline void
__kernel_sincos(double x, double y, int iy, double *sn, double *cs)
{
	double hz, r, v, w, z;

	z = x * x;
	w = z * z;
	r = S2 + z * (S3 + z * S4) + z * w * (S5 + z * S6);
	v = z * x;

	if (iy == 0)
		*sn = x + v * (S1 + z * r);
	else
		*sn = x - ((z * (y / 2 - v * r) - y) - v * S1);

	r = z * (C1 + z * (C2 + z * C3)) + w * w * (C4 + z * (C5 + z * C6));
	hz = z / 2;
	w = 1 - hz;
	*cs = w + (((1 - w) - hz) + (z * r - x * y));
}