The SigmaDSP processors up to the current generation do stream-oriented processing, otherwise known as sample-by-sample processing. This means that a sample is input and output at a rate equal to the sample rate, and those samples are processed sequentially.
In order to do pitch-shift or other frequency-domain processing, an FFT or DFT is required. This cannot be accomplished easily using stream-oriented DSP hardware, because the DSP core architecture is not well-suited to join the samples into blocks and perform frequency-domain processing. For this reason, pitch-shift effects are not possible on current SigmaDSP processors.
If your application requires pitch-shift or other frequency-domain processing, consider using a Sharc or Blackfin, both of which are capable of frequency-domain processing and have these code libraries readily available.
