This may not be possible. You need to frame a truth table to come up with an output mapping. Could you please let us know the difficulty you're facing with the function?
the LUT is 3-inputs. in fact a 3-input truth table is not complex for the combinatorial logic.
users hope it would be easy to achieve combinatorial logic by an expression just as a programmble chip does.
we can see something from LUT configuration window. it seems that there is an easy way to do logic function with listed expression,operators ,etc,in the window.
why does not cypress supply this function?