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 use super::{get_high_word, k_cos, k_sin, rem_pio2};
14
sincos(x: f64) -> (f64, f64)15 pub fn sincos(x: f64) -> (f64, f64) {
16 let s: f64;
17 let c: f64;
18 let mut ix: u32;
19
20 ix = get_high_word(x);
21 ix &= 0x7fffffff;
22
23 /* |x| ~< pi/4 */
24 if ix <= 0x3fe921fb {
25 /* if |x| < 2**-27 * sqrt(2) */
26 if ix < 0x3e46a09e {
27 /* raise inexact if x!=0 and underflow if subnormal */
28 let x1p120 = f64::from_bits(0x4770000000000000); // 0x1p120 == 2^120
29 if ix < 0x00100000 {
30 force_eval!(x / x1p120);
31 } else {
32 force_eval!(x + x1p120);
33 }
34 return (x, 1.0);
35 }
36 return (k_sin(x, 0.0, 0), k_cos(x, 0.0));
37 }
38
39 /* sincos(Inf or NaN) is NaN */
40 if ix >= 0x7ff00000 {
41 let rv = x - x;
42 return (rv, rv);
43 }
44
45 /* argument reduction needed */
46 let (n, y0, y1) = rem_pio2(x);
47 s = k_sin(y0, y1, 1);
48 c = k_cos(y0, y1);
49 match n & 3 {
50 0 => (s, c),
51 1 => (c, -s),
52 2 => (-s, -c),
53 3 => (-c, s),
54 #[cfg(debug_assertions)]
55 _ => unreachable!(),
56 #[cfg(not(debug_assertions))]
57 _ => (0.0, 1.0),
58 }
59 }
60