haddp[sd], hsubp[sd] and addsubp[sd] operate on floats, thus it is
necessary to use the appropriate floating point calculation functions.
If this is not done, those functions operate merely on integers, which
is not correct.
Signed-off-by: NMax Reitz <max@tyndur.org>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>