| use super::{exp2, modf, pow}; |
| |
| const LN10: f64 = 3.32192809488736234787031942948939; |
| const P10: &[f64] = &[ |
| 1e-15, 1e-14, 1e-13, 1e-12, 1e-11, 1e-10, 1e-9, 1e-8, 1e-7, 1e-6, 1e-5, 1e-4, 1e-3, 1e-2, 1e-1, |
| 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, |
| ]; |
| |
| pub fn exp10(x: f64) -> f64 { |
| let (mut y, n) = modf(x); |
| let u: u64 = n.to_bits(); |
| /* fabs(n) < 16 without raising invalid on nan */ |
| if (u >> 52 & 0x7ff) < 0x3ff + 4 { |
| if y == 0.0 { |
| return P10[((n as isize) + 15) as usize]; |
| } |
| y = exp2(LN10 * y); |
| return y * P10[((n as isize) + 15) as usize]; |
| } |
| return pow(10.0, x); |
| } |
