Doron Orenstein

Micro-operation cache: a power aware frontend for the variable instruction length ISA

Introduces the micro-operation cache (Uop Cache-UC) designed to reduce the processors frontend power and energy consumption without performance degradation. The UC caches basic blocks of instructions pre-decoded into micro-operations (uops). The UC fetches a single basic-block worth of uops per cycle. Fetching complete pre-decoded basic-blocks eliminates the need to repeatedly decode variable length instructions and simplifies the process of predicting, fetching, rotating and aligning fetched instructions. The UC design enables even a small structure to be quite effective. Results: a moderate-sized UC eliminates about 75% instruction decodes across a broad range of benchmarks and over 90% in multimedia applications and high-power tests. For existing Intel P6 family processors, the eliminated work may save about 10% of the full-chip power consumption with no performance degradation.