libm/math/
fmodf.rs

1use core::{f32, u32};
2
3#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
4pub fn fmodf(x: f32, y: f32) -> f32 {
5    let mut uxi = x.to_bits();
6    let mut uyi = y.to_bits();
7    let mut ex = (uxi >> 23 & 0xff) as i32;
8    let mut ey = (uyi >> 23 & 0xff) as i32;
9    let sx = uxi & 0x80000000;
10    let mut i;
11
12    if uyi << 1 == 0 || y.is_nan() || ex == 0xff {
13        return (x * y) / (x * y);
14    }
15
16    if uxi << 1 <= uyi << 1 {
17        if uxi << 1 == uyi << 1 {
18            return 0.0 * x;
19        }
20
21        return x;
22    }
23
24    /* normalize x and y */
25    if ex == 0 {
26        i = uxi << 9;
27        while i >> 31 == 0 {
28            ex -= 1;
29            i <<= 1;
30        }
31
32        uxi <<= -ex + 1;
33    } else {
34        uxi &= u32::MAX >> 9;
35        uxi |= 1 << 23;
36    }
37
38    if ey == 0 {
39        i = uyi << 9;
40        while i >> 31 == 0 {
41            ey -= 1;
42            i <<= 1;
43        }
44
45        uyi <<= -ey + 1;
46    } else {
47        uyi &= u32::MAX >> 9;
48        uyi |= 1 << 23;
49    }
50
51    /* x mod y */
52    while ex > ey {
53        i = uxi.wrapping_sub(uyi);
54        if i >> 31 == 0 {
55            if i == 0 {
56                return 0.0 * x;
57            }
58            uxi = i;
59        }
60        uxi <<= 1;
61
62        ex -= 1;
63    }
64
65    i = uxi.wrapping_sub(uyi);
66    if i >> 31 == 0 {
67        if i == 0 {
68            return 0.0 * x;
69        }
70        uxi = i;
71    }
72
73    while uxi >> 23 == 0 {
74        uxi <<= 1;
75        ex -= 1;
76    }
77
78    /* scale result up */
79    if ex > 0 {
80        uxi -= 1 << 23;
81        uxi |= (ex as u32) << 23;
82    } else {
83        uxi >>= -ex + 1;
84    }
85    uxi |= sx;
86
87    f32::from_bits(uxi)
88}
libm/math/fmodf.rs

libm/math/
fmodf.rs
