libm/math/
scalbnf.rs

1#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
2pub fn scalbnf(mut x: f32, mut n: i32) -> f32 {
3    let x1p127 = f32::from_bits(0x7f000000); // 0x1p127f === 2 ^ 127
4    let x1p_126 = f32::from_bits(0x800000); // 0x1p-126f === 2 ^ -126
5    let x1p24 = f32::from_bits(0x4b800000); // 0x1p24f === 2 ^ 24
6
7    if n > 127 {
8        x *= x1p127;
9        n -= 127;
10        if n > 127 {
11            x *= x1p127;
12            n -= 127;
13            if n > 127 {
14                n = 127;
15            }
16        }
17    } else if n < -126 {
18        x *= x1p_126 * x1p24;
19        n += 126 - 24;
20        if n < -126 {
21            x *= x1p_126 * x1p24;
22            n += 126 - 24;
23            if n < -126 {
24                n = -126;
25            }
26        }
27    }
28    x * f32::from_bits(((0x7f + n) as u32) << 23)
29}