1 | use core::f32; |
2 | use core::u32; |
3 | |
4 | #[cfg_attr (all(test, assert_no_panic), no_panic::no_panic)] |
5 | pub fn fmodf(x: f32, y: f32) -> f32 { |
6 | let mut uxi = x.to_bits(); |
7 | let mut uyi = y.to_bits(); |
8 | let mut ex = (uxi >> 23 & 0xff) as i32; |
9 | let mut ey = (uyi >> 23 & 0xff) as i32; |
10 | let sx = uxi & 0x80000000; |
11 | let mut i; |
12 | |
13 | if uyi << 1 == 0 || y.is_nan() || ex == 0xff { |
14 | return (x * y) / (x * y); |
15 | } |
16 | |
17 | if uxi << 1 <= uyi << 1 { |
18 | if uxi << 1 == uyi << 1 { |
19 | return 0.0 * x; |
20 | } |
21 | |
22 | return x; |
23 | } |
24 | |
25 | /* normalize x and y */ |
26 | if ex == 0 { |
27 | i = uxi << 9; |
28 | while i >> 31 == 0 { |
29 | ex -= 1; |
30 | i <<= 1; |
31 | } |
32 | |
33 | uxi <<= -ex + 1; |
34 | } else { |
35 | uxi &= u32::MAX >> 9; |
36 | uxi |= 1 << 23; |
37 | } |
38 | |
39 | if ey == 0 { |
40 | i = uyi << 9; |
41 | while i >> 31 == 0 { |
42 | ey -= 1; |
43 | i <<= 1; |
44 | } |
45 | |
46 | uyi <<= -ey + 1; |
47 | } else { |
48 | uyi &= u32::MAX >> 9; |
49 | uyi |= 1 << 23; |
50 | } |
51 | |
52 | /* x mod y */ |
53 | while ex > ey { |
54 | i = uxi.wrapping_sub(uyi); |
55 | if i >> 31 == 0 { |
56 | if i == 0 { |
57 | return 0.0 * x; |
58 | } |
59 | uxi = i; |
60 | } |
61 | uxi <<= 1; |
62 | |
63 | ex -= 1; |
64 | } |
65 | |
66 | i = uxi.wrapping_sub(uyi); |
67 | if i >> 31 == 0 { |
68 | if i == 0 { |
69 | return 0.0 * x; |
70 | } |
71 | uxi = i; |
72 | } |
73 | |
74 | while uxi >> 23 == 0 { |
75 | uxi <<= 1; |
76 | ex -= 1; |
77 | } |
78 | |
79 | /* scale result up */ |
80 | if ex > 0 { |
81 | uxi -= 1 << 23; |
82 | uxi |= (ex as u32) << 23; |
83 | } else { |
84 | uxi >>= -ex + 1; |
85 | } |
86 | uxi |= sx; |
87 | |
88 | f32::from_bits(uxi) |
89 | } |
90 | |