Floating point multiplication megafunction

Fixed point is simply just binary. Imagine the number 9.25

In 6 bit fixed point:b 1001.01

This is the same as 37: 100101

The only difference is a decimal place. So with fixed point arithmatic the decimal point (should probably be called the integer/fraction divider!) is just imaginary, so you would treat the fixed point number as if it was 37.

The following rules apply:

An M.N number + X.Y results in a max(M, X)+1.min(N, Y) number.

M.N * X.Y = M+X.N+Y

(Where M,N,X,Y are the number of bits).

Have a look at the VHDL fixed point package:

www.vhdl.org/fphdl

Its the 2008 fixed point package in 93 format so you can use it with any synthesisor.