A processor has: a power table including a plurality of power control registers each rewritably storing power control information; a condition determiner for rewritably storing a plurality of operating conditions (e.g., a comparison address to be compared with the program counter) and determining which one of the plurality of operating conditions is satisfied by a current operation of the processor so as to supply an index signal to select one of the plurality of power control registers based on the determination; and a voltage/clock controller for controlling the power consumption in a control object circuit block according to the power control information in one of the power control registers that is selected by the index signal.