In case you have to do complicated calculus, how about implementing analog circuits (Integrators and Differentiators)? You give the input from a DAC and measure the processed output using ADC.

However the capacitive components in the circuits must be discharged between any two "calculations" or else the residual Capacitance would adversely affect subsequent calculations.

Dunno if it is feasible, but it might work faster for complex operations? I believe this is how they implemented control systems before the advent of digital technology... In fact they often used to do these manipulations using PNEUMATIC circuits! :-)

kundi