| use super::expm1f; |
| |
| #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
| pub fn tanhf(mut x: f32) -> f32 { |
| /* x = |x| */ |
| let mut ix = x.to_bits(); |
| let sign = (ix >> 31) != 0; |
| ix &= 0x7fffffff; |
| x = f32::from_bits(ix); |
| let w = ix; |
| |
| let tt = if w > 0x3f0c9f54 { |
| /* |x| > log(3)/2 ~= 0.5493 or nan */ |
| if w > 0x41200000 { |
| /* |x| > 10 */ |
| 1. + 0. / x |
| } else { |
| let t = expm1f(2. * x); |
| 1. - 2. / (t + 2.) |
| } |
| } else if w > 0x3e82c578 { |
| /* |x| > log(5/3)/2 ~= 0.2554 */ |
| let t = expm1f(2. * x); |
| t / (t + 2.) |
| } else if w >= 0x00800000 { |
| /* |x| >= 0x1p-126 */ |
| let t = expm1f(-2. * x); |
| -t / (t + 2.) |
| } else { |
| /* |x| is subnormal */ |
| force_eval!(x * x); |
| x |
| }; |
| if sign { |
| -tt |
| } else { |
| tt |
| } |
| } |
