Saving register-file static power by monitoring short-lived temporary-values in ROB

Modern portable or multimedia applications make embedded processors require not only low power-consumption, but also high computing performance. The reorder buffer (ROB) and the register file are the two critical components to enhance a processor's IIP, but they unfortunately have serious static power, especially occurred in a large register file. In this paper, we use a hardware-based approach to reduce the static power of a register file. In the proposed approach, we design a monitoring mechanism in the ROB to identify which temporary values are shortlived. These values will potentially make registers become idle. A DVS mechanism can then be applied to power down those registers which store short-lived temporary values. Simulation results show that through ROB monitoring, a register file can save at least 50% static power consumption with almost negligible performance loss.