1use core::f32;
2
3/// Ceil (f32)
4///
5/// Finds the nearest integer greater than or equal to `x`.
6#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
7pub fn ceilf(x: f32) -> f32 {
8 // On wasm32 we know that LLVM's intrinsic will compile to an optimized
9 // `f32.ceil` native instruction, so we can leverage this for both code size
10 // and speed.
11 llvm_intrinsically_optimized! {
12 #[cfg(target_arch = "wasm32")] {
13 return unsafe { ::core::intrinsics::ceilf32(x) }
14 }
15 }
16 let mut ui = x.to_bits();
17 let e = (((ui >> 23) & 0xff).wrapping_sub(0x7f)) as i32;
18
19 if e >= 23 {
20 return x;
21 }
22 if e >= 0 {
23 let m = 0x007fffff >> e;
24 if (ui & m) == 0 {
25 return x;
26 }
27 force_eval!(x + f32::from_bits(0x7b800000));
28 if ui >> 31 == 0 {
29 ui += m;
30 }
31 ui &= !m;
32 } else {
33 force_eval!(x + f32::from_bits(0x7b800000));
34 if ui >> 31 != 0 {
35 return -0.0;
36 } else if ui << 1 != 0 {
37 return 1.0;
38 }
39 }
40 f32::from_bits(ui)
41}
42
43// PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520
44#[cfg(not(target_arch = "powerpc64"))]
45#[cfg(test)]
46mod tests {
47 use core::f32::*;
48
49 use super::*;
50
51 #[test]
52 fn sanity_check() {
53 assert_eq!(ceilf(1.1), 2.0);
54 assert_eq!(ceilf(2.9), 3.0);
55 }
56
57 /// The spec: https://en.cppreference.com/w/cpp/numeric/math/ceil
58 #[test]
59 fn spec_tests() {
60 // Not Asserted: that the current rounding mode has no effect.
61 assert!(ceilf(NAN).is_nan());
62 for f in [0.0, -0.0, INFINITY, NEG_INFINITY].iter().copied() {
63 assert_eq!(ceilf(f), f);
64 }
65 }
66}
67