A processor responsive to a clock cycle includes a base-unit, a mirror-unit that is a duplicate instance of the base-unit, a non-duplicate-unit in signal communication with the base and mirror units, a first staging register disposed at the input to the mirror-unit for delaying the input signal thereto by at least one clock cycle, and a second staging register disposed at the output of the mirror-unit for delaying the output signal therefrom by at least one clock cycle. The non-duplicate-unit includes a comparator for comparing the output signals of the base and mirror units.