Function rustc_apfloat::ieee::sig::mul

pub(in ieee) fn mul<'a>(
    dst: &mut [u128], 
    exp: &mut ExpInt, 
    a: &'a [u128], 
    b: &'a [u128], 
    precision: usize
) -> Loss

dst = a * b (for normal a and b). Returns the lost fraction.