CPU架构的8位FFT？

I am looking for an FFT engine that can handle 8-bit real to complex transforms (of size 65K). The need for this is to accelerate a real-time signal processing engine. It is currently limited by 8-bit -> FP32 and FP32 -> 8-bit conversions, as well as the actual FFT being memory bandwidth bound (we're using FFTW at the moment).I am looking for an FFT engine that can handle