1use core::f32;
2
3#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
4pub fn truncf(x: f32) -> f32 {
5 // On wasm32 we know that LLVM's intrinsic will compile to an optimized
6 // `f32.trunc` native instruction, so we can leverage this for both code size
7 // and speed.
8 llvm_intrinsically_optimized! {
9 #[cfg(target_arch = "wasm32")] {
10 return unsafe { ::core::intrinsics::truncf32(x) }
11 }
12 }
13 let x1p120 = f32::from_bits(0x7b800000); // 0x1p120f === 2 ^ 120
14
15 let mut i: u32 = x.to_bits();
16 let mut e: i32 = (i >> 23 & 0xff) as i32 - 0x7f + 9;
17 let m: u32;
18
19 if e >= 23 + 9 {
20 return x;
21 }
22 if e < 9 {
23 e = 1;
24 }
25 m = -1i32 as u32 >> e;
26 if (i & m) == 0 {
27 return x;
28 }
29 force_eval!(x + x1p120);
30 i &= !m;
31 f32::from_bits(i)
32}
33
34// PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520
35#[cfg(not(target_arch = "powerpc64"))]
36#[cfg(test)]
37mod tests {
38 #[test]
39 fn sanity_check() {
40 assert_eq!(super::truncf(1.1), 1.0);
41 }
42}
43