Clustered L0 Buffer Organization for Low Energy Embedded Processors

Current L0 or loop buffer organizations for VLIW processors are essentially centralized, as a consequence they are energy inefficient and their scalability is limited. In this context, we propose a clustered loop buffer organization, where the loop buffers are partitioned and functional units are logically grouped to form instruction clusters, along with two schemes for the buffer control which regulate the activity in each cluster. To demonstrate the efficiency of the proposed schemes, we compare their energy consumption against an uncompressed centralized buffer, a compressed centralized buffer and an uncompressed partitioned scheme with no buffer control. Furthermore, we present an extended version of our functional unit activity based clustering scheme to form instruction clusters for each application. The simulation results indicate that the energy consumed in the clustered L0 buffers is on average 63% lower than the energy consumed in an uncompressed centralized L0 buffer.