Pic's are microcontrollers, they ... control stuff and are not designed to do much math. If you want to do some serious number crunching you should be looking for a CPU system instead of a µC system
There are floating point libraries available for many micros (dont know about PICs, I prefer AVRs) -- It takes many cycles. You should always evaluate your problem to make sure that floating point is really needed. for instance, converting period to frequency on the surface requires 1/t. However, if you consider that the unit of t is usually ticks, you can work out an integer approximation.