A microprogramming approach to low-power microprocessor design
C. Papachristou, Mansoor A. Khan · 1998
Reduction of power consumption in VLSI design is important for two reasons: the need for an extended battery life in hand-held computers and communication devices; and for integration of greater number of transistors on a single chip. In this dissertation, we show that microprogramming can be used effectively for low power consumption in the control unit of a microprocessor. We propose a microprogrammed control unit design that can lead to lower power consumption than in a hardwired control unit. We analyze the effect of control signals encoding on the power consumption in the control store section of the microprogrammed control unit. We offer a method to optimality encode control signals for reducing the power consumption in the control store. We also evaluate distributed microcode memory model for its power consumption. We suggest a technique to be employed during the design of the distributed microcode memory modules, which leads to lower power consumption. We show that distributed microcode design can be used to further reduce power consumption in a microprogrammed control unit. We utilize the above techniques to design microprogrammed control units for two microprocessors and achieve a substantial power savings in both cases, compared to the hardwired implementation of their control units.