Use of divide1616 and idivide1616 with constant denominator

The use of the division routine is useful, if the denominator is dynamic in a greater range. For all constant denominators, a constant can be defined to use it in a multiplication: result = divide1616(num, const den) => result = mult(num, INV_DEN) or similar.

By using a grep command, I see already more than 80 places (idiv1616 only) in the code, that could be changed, even **a denominator of "2" **is sometimes used, obviously something to simplify. See: idiv1616.txt attached