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49aad941 FG |
1 | #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
2 | pub fn rintf(x: f32) -> f32 { | |
3 | let one_over_e = 1.0 / f32::EPSILON; | |
4 | let as_u32: u32 = x.to_bits(); | |
5 | let exponent: u32 = as_u32 >> 23 & 0xff; | |
6 | let is_positive = (as_u32 >> 31) == 0; | |
7 | if exponent >= 0x7f + 23 { | |
8 | x | |
9 | } else { | |
10 | let ans = if is_positive { | |
4b012472 FG |
11 | #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))] |
12 | let x = force_eval!(x); | |
13 | let xplusoneovere = x + one_over_e; | |
14 | #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))] | |
15 | let xplusoneovere = force_eval!(xplusoneovere); | |
16 | xplusoneovere - one_over_e | |
49aad941 | 17 | } else { |
4b012472 FG |
18 | #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))] |
19 | let x = force_eval!(x); | |
20 | let xminusoneovere = x - one_over_e; | |
21 | #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))] | |
22 | let xminusoneovere = force_eval!(xminusoneovere); | |
23 | xminusoneovere + one_over_e | |
49aad941 FG |
24 | }; |
25 | ||
26 | if ans == 0.0 { | |
27 | if is_positive { | |
28 | 0.0 | |
29 | } else { | |
30 | -0.0 | |
31 | } | |
32 | } else { | |
33 | ans | |
34 | } | |
35 | } | |
36 | } | |
37 | ||
38 | // PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520 | |
39 | #[cfg(not(target_arch = "powerpc64"))] | |
40 | #[cfg(test)] | |
41 | mod tests { | |
42 | use super::rintf; | |
43 | ||
44 | #[test] | |
45 | fn negative_zero() { | |
46 | assert_eq!(rintf(-0.0_f32).to_bits(), (-0.0_f32).to_bits()); | |
47 | } | |
48 | ||
49 | #[test] | |
50 | fn sanity_check() { | |
51 | assert_eq!(rintf(-1.0), -1.0); | |
52 | assert_eq!(rintf(2.8), 3.0); | |
53 | assert_eq!(rintf(-0.5), -0.0); | |
54 | assert_eq!(rintf(0.5), 0.0); | |
55 | assert_eq!(rintf(-1.5), -2.0); | |
56 | assert_eq!(rintf(1.5), 2.0); | |
57 | } | |
58 | } |