add fast path to integer_multiply for small numbers
add fast path to integer_multiply for small numbers

TyRoXx/Lpg,mamazu/Lpg,TyRoXx/Lpg,TyRoXx/Lpg,mamazu/Lpg,mamazu/Lpg,TyRoXx/Lpg,mamazu/Lpg,TyRoXx/Lpg