Why can't double precision data in Unified FFT ip get correct results?

[ming1]

  Hi,

  I use the single precision option in unifiedfftip. It works well. (256point ，sampling frequency is 12800hz.The input is   3.14e8*sin2pi50t, and the output of FFT IP is -4.0192e10 , which equal to 3.14e8*(256/2)).

But when I change single precision to double precision and change the input data into double precision floating-point numbers of the same size, it can't get correct results.

Do I need to add other designs to realize Double precision fft or Double precision FFT cannot be realized in unifed fft ip?