1/* origin: FreeBSD /usr/src/lib/msun/src/s_sin.c */
2/*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12
13#define _GNU_SOURCE
14#include "libm.h"
15
16void sincos(double x, double *sin, double *cos)
17{
18	double y[2], s, c;
19	uint32_t ix;
20	unsigned n;
21
22	GET_HIGH_WORD(ix, x);
23	ix &= 0x7fffffff;
24
25	/* |x| ~< pi/4 */
26	if (ix <= 0x3fe921fb) {
27		/* if |x| < 2**-27 * sqrt(2) */
28		if (ix < 0x3e46a09e) {
29			/* raise inexact if x!=0 and underflow if subnormal */
30			FORCE_EVAL(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f);
31			*sin = x;
32			*cos = 1.0;
33			return;
34		}
35		*sin = __sin(x, 0.0, 0);
36		*cos = __cos(x, 0.0);
37		return;
38	}
39
40	/* sincos(Inf or NaN) is NaN */
41	if (ix >= 0x7ff00000) {
42		*sin = *cos = x - x;
43		return;
44	}
45
46	/* argument reduction needed */
47	n = __rem_pio2(x, y);
48	s = __sin(y[0], y[1], 1);
49	c = __cos(y[0], y[1]);
50	switch (n&3) {
51	case 0:
52		*sin = s;
53		*cos = c;
54		break;
55	case 1:
56		*sin = c;
57		*cos = -s;
58		break;
59	case 2:
60		*sin = -s;
61		*cos = -c;
62		break;
63	case 3:
64	default:
65		*sin = -c;
66		*cos = s;
67		break;
68	}
69}
70