| /* origin: FreeBSD /usr/src/lib/msun/src/s_sin.c */ |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunPro, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| use super::{get_high_word, k_cos, k_sin, rem_pio2}; |
| |
| pub fn sincos(x: f64) -> (f64, f64) { |
| let s: f64; |
| let c: f64; |
| let mut ix: u32; |
| |
| ix = get_high_word(x); |
| ix &= 0x7fffffff; |
| |
| /* |x| ~< pi/4 */ |
| if ix <= 0x3fe921fb { |
| /* if |x| < 2**-27 * sqrt(2) */ |
| if ix < 0x3e46a09e { |
| /* raise inexact if x!=0 and underflow if subnormal */ |
| let x1p120 = f64::from_bits(0x4770000000000000); // 0x1p120 == 2^120 |
| if ix < 0x00100000 { |
| force_eval!(x / x1p120); |
| } else { |
| force_eval!(x + x1p120); |
| } |
| return (x, 1.0); |
| } |
| return (k_sin(x, 0.0, 0), k_cos(x, 0.0)); |
| } |
| |
| /* sincos(Inf or NaN) is NaN */ |
| if ix >= 0x7ff00000 { |
| let rv = x - x; |
| return (rv, rv); |
| } |
| |
| /* argument reduction needed */ |
| let (n, y0, y1) = rem_pio2(x); |
| s = k_sin(y0, y1, 1); |
| c = k_cos(y0, y1); |
| match n & 3 { |
| 0 => (s, c), |
| 1 => (c, -s), |
| 2 => (-s, -c), |
| 3 => (-c, s), |
| #[cfg(feature = "checked")] |
| _ => unreachable!(), |
| #[cfg(not(feature = "checked"))] |
| _ => (0.0, 1.0), |
| } |
| } |
