FFT megaCore usage problem

I am using "Timing" mode in the Simulator Tool there... Is it because I did the simulation in timing mode that result in all these random value or noise?

I would like to ask in my control unit, I would like to control the source_ready signal where this signal is '1' when the data_real is available and '0' when the data_real is not available

Can I do the coding like this?

if(data_real) then

source_ready<='1';

else

source_ready<='0';

end if;

in my vhdl code of CU.