const_soft_float/soft_f32/
floor.rs

1use super::SoftF32;
2
3/// Floor (SoftF32)
4///
5/// Finds the nearest integer less than or equal to `x`.
6pub const fn floor(x: SoftF32) -> SoftF32 {
7    let mut ui = x.to_bits();
8    let e = (((ui >> 23) as i32) & 0xff) - 0x7f;
9
10    if e >= 23 {
11        return x;
12    }
13    if e >= 0 {
14        let m: u32 = 0x007fffff >> e;
15        if (ui & m) == 0 {
16            return x;
17        }
18        // force_eval!(x + SoftF32::from_bits(0x7b800000));
19        if ui >> 31 != 0 {
20            ui += m;
21        }
22        ui &= !m;
23    } else {
24        // force_eval!(x + SoftF32::from_bits(0x7b800000));
25        if ui >> 31 == 0 {
26            ui = 0;
27        } else if ui << 1 != 0 {
28            return SoftF32(-1.0);
29        }
30    }
31    SoftF32::from_bits(ui)
32}
33
34#[cfg(test)]
35mod tests {
36    use super::*;
37
38    #[test]
39    fn sanity_check() {
40        assert_eq!(floor(SoftF32(0.5)).0, 0.0);
41        assert_eq!(floor(SoftF32(1.1)).0, 1.0);
42        assert_eq!(floor(SoftF32(2.9)).0, 2.0);
43    }
44
45    /// The spec: https://en.cppreference.com/w/cpp/numeric/math/floor
46    #[test]
47    fn spec_tests() {
48        // Not Asserted: that the current rounding mode has no effect.
49        assert!(floor(SoftF32(f32::NAN)).0.is_nan());
50        for f in [0.0, -0.0, f32::INFINITY, f32::NEG_INFINITY]
51            .iter()
52            .copied()
53        {
54            assert_eq!(SoftF32(f).floor().0, f);
55        }
56    }
57}
const_soft_float/soft_f32/floor.rs

const_soft_float/soft_f32/
floor.rs
