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Commit | Line | Data |
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dc9dc135 XL |
1 | /// Absolute value (magnitude) (f32) |
2 | /// Calculates the absolute value (magnitude) of the argument `x`, | |
3 | /// by direct manipulation of the bit representation of `x`. | |
48663c56 | 4 | #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
8faf50e0 | 5 | pub fn fabsf(x: f32) -> f32 { |
a1dfa0c6 XL |
6 | // On wasm32 we know that LLVM's intrinsic will compile to an optimized |
7 | // `f32.abs` native instruction, so we can leverage this for both code size | |
8 | // and speed. | |
9 | llvm_intrinsically_optimized! { | |
10 | #[cfg(target_arch = "wasm32")] { | |
11 | return unsafe { ::core::intrinsics::fabsf32(x) } | |
12 | } | |
13 | } | |
8faf50e0 XL |
14 | f32::from_bits(x.to_bits() & 0x7fffffff) |
15 | } | |
60c5eb7d XL |
16 | |
17 | #[cfg(test)] | |
18 | mod tests { | |
19 | use super::*; | |
20 | use core::f32::*; | |
21 | ||
22 | #[test] | |
23 | fn sanity_check() { | |
24 | assert_eq!(fabsf(-1.0), 1.0); | |
25 | assert_eq!(fabsf(2.8), 2.8); | |
26 | } | |
27 | ||
28 | /// The spec: https://en.cppreference.com/w/cpp/numeric/math/fabs | |
29 | #[test] | |
30 | fn spec_tests() { | |
31 | assert!(fabsf(NAN).is_nan()); | |
32 | for f in [0.0, -0.0].iter().copied() { | |
33 | assert_eq!(fabsf(f), 0.0); | |
34 | } | |
35 | for f in [INFINITY, NEG_INFINITY].iter().copied() { | |
36 | assert_eq!(fabsf(f), INFINITY); | |
37 | } | |
38 | } | |
39 | } |