This function does Complex (in-place) Bit Reverse re-organization.

• N: buffer length (must be the power of 2).
• ReIm: output sample(from FFT).

Nothing.

Nothing.

var InputSamples: array[512] of word; ydata;     // Y data is required by FFT routine
                                                 // See datasheet for your dsPIC to see Y data space limits.

...

// Perform FFT (DFT), 7 stages, 128 samples of complex pairs
// Twiddle factors are taken from help
FFT(8, word(@TwiddleCoeff_256), InputSamples);

// DFT butterfly algorythm bit-reverses output samples.
// We have to restore them in natural order.
BitReverseComplex(8, InputSamples);

Input samples must be in Y data space.