Neil C. Wilhelm

Caching processor general registers

VLIW, multi-context, or windowed-register architectures may require one hundred or more processor registers. It can be difficult to design a register file with so many registers that meets processor cycle time requirements. We propose to resolve this problem by taking advantage of register values that are bypassed within a processors pipeline, and supplementing the bypassed values with values supplied by a small register cache. If the register cache is sufficiently small then it can be designed to meet a fast target cycle time. We call this combination of bypassing and register caching the register scoreboard and cache. We develop a simple performance model and show by simulations that it can be effective for windowed-register architectures.