a) LAZY and didn't actually type "vhdl code in 256 points FFT" into google.
Oooohhh look there is an Opencores link at the bottom!
b) are in a country that filters (restricts) your access to the internet including being able to do a proper search for anything useful (if that is the case I'm very sorry for you).
c) are utterly incompetent at using a search engine, maybe you need computer training first.
If you can't find the code on opencores then you are beyond help. I'm not going to waste time spoon feeding you, because you lack the skill to even click on links after typing in the URL, from that picture of the google results, into you browser (i.e. you know the line of greenish text that has the https garbage in it).