Floating point multiplication megafunction

If you have say a multiplier that has two inputs (signal 12 bits signed and multiplicand 12 bits signed) then you may truncate 12 LSB bits off result.

That is equivalent to /2^12.

Thus if your multiplicand is 0.172212 then you first pre-convert it 0.172212*2^12 by hand and round it to 705.

thus when you truncate 12 LSBs, in effect you multiply by 0.172212

Thus all you do is scale your mutiplicand from normalised range of (-1 ~ 1)

by scaling it by 2^12.

You can additionally do rounding at truncation.

Edit: additionally you can think of it in your head as fractional value with decimal point somewhere but you don't need to as it is just two ways of looking at same thing.