Commit 22563513 authored by Pierre Donat-Bouillud's avatar Pierre Donat-Bouillud
Browse files

fmod function for f32

parent 19c42185
//! Add to math functions neede only_externals
use std::u32;
#[inline]
pub fn fmod(x: f32, y: f32) -> f32 {
let mut uxi = x.to_bits();
let mut uyi = y.to_bits();
let mut ex = (uxi >> 23 & 0xff) as i32;
let mut ey = (uyi >> 23 & 0xff) as i32;
let sx = uxi & 0x80000000;
let mut i;
if uyi << 1 == 0 || y.is_nan() || ex == 0xff {
return (x * y) / (x * y);
}
if uxi << 1 <= uyi << 1 {
if uxi << 1 == uyi << 1 {
return 0.0 * x;
}
return x;
}
/* normalize x and y */
if ex == 0 {
i = uxi << 9;
while i >> 31 == 0 {
ex -= 1;
i <<= 1;
}
uxi <<= -ex + 1;
} else {
uxi &= u32::MAX >> 9;
uxi |= 1 << 23;
}
if ey == 0 {
i = uyi << 9;
while i >> 31 == 0 {
ey -= 1;
i <<= 1;
}
uyi <<= -ey + 1;
} else {
uyi &= u32::MAX >> 9;
uyi |= 1 << 23;
}
/* x mod y */
while ex > ey {
i = uxi - uyi;
if i >> 31 == 0 {
if i == 0 {
return 0.0 * x;
}
uxi = i;
}
uxi <<= 1;
ex -= 1;
}
i = uxi - uyi;
if i >> 31 == 0 {
if i == 0 {
return 0.0 * x;
}
uxi = i;
}
while uxi >> 23 == 0 {
uxi <<= 1;
ex -= 1;
}
/* scale result */
if ex > 0 {
uxi -= 1 << 23;
uxi |= (ex as u32) << 23;
} else {
uxi >>= -ex + 1;
}
uxi |= sx; //(sx as u32) << 63;
f32::from_bits(uxi)
}
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