An activity-driven encoding scheme for power optimization in microprogrammed control unit

With the high demand for reliability and further integration, power consumption has become a critical concern in today´s very large scale integration design. Considering the different techniques to minimize power consumption and promote system´s reliability, reducing switching activity of CMOS circuits is a promising area to be explored. In this paper, we present a encoding scheme to refine the control memory in a microprogrammed control unit, which can reduce switching activities within the control unit and on the path from control unit to data-processing unit. To achieve this, pseudo-Boolean programming techniques have been introduced to efficiently encode don´t care bits in the control memory. Experiments have been conducted with a subset of 8086 instruction set. Results show that, 4.8%-16.5% reduction of switching activities can be obtained from the proposed encoding scheme.