pub fn modff(x: f32) -> (f32, f32) {

    let rv2: f32;

    let mut u: u32 = x.to_bits();

    let mask: u32;

    let e = ((u >> 23 & 0xff) as i32) - 0x7f;

    /* no fractional part */

    if e >= 23 {

        rv2 = x;

        if e == 0x80 && (u << 9) != 0 {

            /* nan */

            return (x, rv2);

        }

        u &= 0x80000000;

        return (f32::from_bits(u), rv2);

    }

    /* no integral part */

    if e < 0 {

        u &= 0x80000000;

        rv2 = f32::from_bits(u);

        return (x, rv2);

    }

    mask = 0x007fffff >> e;

    if (u & mask) == 0 {

        rv2 = x;

        u &= 0x80000000;

        return (f32::from_bits(u), rv2);

    }

    u &= !mask;

    rv2 = f32::from_bits(u);

    return (x - rv2, rv2);

}