| #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
| pub fn rint(x: f64) -> f64 { |
| let one_over_e = 1.0 / f64::EPSILON; |
| let as_u64: u64 = x.to_bits(); |
| let exponent: u64 = as_u64 >> 52 & 0x7ff; |
| let is_positive = (as_u64 >> 63) == 0; |
| if exponent >= 0x3ff + 52 { |
| x |
| } else { |
| let ans = if is_positive { |
| x + one_over_e - one_over_e |
| } else { |
| x - one_over_e + one_over_e |
| }; |
| |
| if ans == 0.0 { |
| if is_positive { |
| 0.0 |
| } else { |
| -0.0 |
| } |
| } else { |
| ans |
| } |
| } |
| } |
| |
| // PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520 |
| #[cfg(not(target_arch = "powerpc64"))] |
| #[cfg(test)] |
| mod tests { |
| use super::rint; |
| |
| #[test] |
| fn negative_zero() { |
| assert_eq!(rint(-0.0_f64).to_bits(), (-0.0_f64).to_bits()); |
| } |
| |
| #[test] |
| fn sanity_check() { |
| assert_eq!(rint(-1.0), -1.0); |
| assert_eq!(rint(2.8), 3.0); |
| assert_eq!(rint(-0.5), -0.0); |
| assert_eq!(rint(0.5), 0.0); |
| assert_eq!(rint(-1.5), -2.0); |
| assert_eq!(rint(1.5), 2.0); |
| } |
| } |
