get()
- interpolate if really necessary

adjust()
- if drop   -> need to get() again
- if interp -> need to skip the next get()? (or just remember for next time)

double-check potential overflows (make explicit run-time checks?)
explicit checks to make sure we *never* divide by zero or have infinite loops
Reset AEC if really gone bad
MCRA update only when st->ps isn't too high?
Verify that the PSHR operators don't cause overflows on intermediate results.

enforce limit on:
- st->ps, st->noise, ...

*use the sign-bit counter on Blackfin (for log2 and sqrt)
*optimise MIN/MAX on Blackfin (or let the compiler do it?)
Use ASHIFT on Blackfin

-> What did it mean?
increase resolution on st->ps ???
increase resolution on st->old_ps ?
look into the details of tot_noise (why again?)
fix the PSHR stuff properly (done?)

Future work:
Implement IMCRA
Fix AGC, VAD
use min(aec_input, aec_output) as preprocessor input?
gain floor average in the amplitude domain?