Multiplication on floating point format

A megafunction is a block of Altera IP. Most of it is written in VHDL and/or verilog, so you can simulate it alongside your own bits of HDL. You can create megafunction blocks via the Megawizard in the tools menu. The megawizard will create VHDL files with all of the setup parameters already specified (or if you are more confident, instantiate them straight from your VHDL - you can get all the parameters in the megafunction help section). These can be instantiated in your VHDL. You just treat them as a black box.