pub fn modf(x: f64) -> (f64, f64) {
let rv2: f64;
let mut u = x.to_bits();
let mask: u64;
let e = ((u >> 52 & 0x7ff) as i32) - 0x3ff;
/* no fractional part */
if e >= 52 {
rv2 = x;
if e == 0x400 && (u << 12) != 0 {
/* nan */
return (x, rv2);
}
u &= 1 << 63;
return (f64::from_bits(u), rv2);
}
/* no integral part*/
if e < 0 {
u &= 1 << 63;
rv2 = f64::from_bits(u);
return (x, rv2);
}
mask = ((!0) >> 12) >> e;
if (u & mask) == 0 {
rv2 = x;
u &= 1 << 63;
return (f64::from_bits(u), rv2);
}
u &= !mask;
rv2 = f64::from_bits(u);
return (x - rv2, rv2);
}