1use super::{expf, expm1f, k_expo2f};
2
3/// Hyperbolic cosine (f64)
4///
5/// Computes the hyperbolic cosine of the argument x.
6/// Is defined as `(exp(x) + exp(-x))/2`
7/// Angles are specified in radians.
8#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
9pub fn coshf(mut x: f32) -> f32 {
10 let x1p120 = f32::from_bits(0x7b800000); // 0x1p120f === 2 ^ 120
11
12 /* |x| */
13 let mut ix = x.to_bits();
14 ix &= 0x7fffffff;
15 x = f32::from_bits(ix);
16 let w = ix;
17
18 /* |x| < log(2) */
19 if w < 0x3f317217 {
20 if w < (0x3f800000 - (12 << 23)) {
21 force_eval!(x + x1p120);
22 return 1.;
23 }
24 let t = expm1f(x);
25 return 1. + t * t / (2. * (1. + t));
26 }
27
28 /* |x| < log(FLT_MAX) */
29 if w < 0x42b17217 {
30 let t = expf(x);
31 return 0.5 * (t + 1. / t);
32 }
33
34 /* |x| > log(FLT_MAX) or nan */
35 k_expo2f(x)
36}
37