Avoid Float

Before the release of the Pentium CPU, it was common for game authors to do as much as possible with integer math. With the Pentium, the floating point math co-processor became a built-in feature, and by interleaving integer and floating-point operations your game would actually go faster than it would with purely integer math. The common practice on desktop systems is to use floating point freely.

Unfortunately, embedded processors frequently do not have hardware floating point support, so all operations on "float" and "double" are performed in software. Some basic floating point operations can take on the order of a millisecond to complete.

Also, even for integers, some chips have hardware multiply but lack hardware divide. In such cases, integer division and modulus operations are performed in software — something to think about if you're designing a hash table or doing lots of math.