A Content Aware Integer Register File Organization

Abstract

A register file is a critical component of a modernsuperscalar processor.It has a large number of entriesand read/write ports in order to enable high levels ofinstruction parallelism.As a result, the register file'sarea, access time, and energy consumption increasedramatically, significantly affecting the overallsuperscalar processor's performance and energyconsumption.This is especially true in 64-bitprocessors.This paper presents a new integer register fileorganization, which reduces energy consumption,area, and access time of the register file with a minimal effect on overall IPC.This is accomplished byexpoiting a new concept, partial value locality, whichis defined as occurence of mutiple live valueinstances identical in a subset of their bits.A possibleimplementation of the new register file is describedand shown to obtain proposed optimized register filedesigns.Overall, an energy reduction of over 50%, a18% decreas in area, and a 15% reduction in the accesstime are achieved in the new register file.Theenergy and area savings are achieved with a 1.7%reduction in IPC for integer applications and anegligible 0.3% in numerical applications, assumingthe same clock frequency.A performance increase ofup to 13% is possible if the clcok frequency can beincreases due to a reduction in the register file accesstime.This approach enables other, very promisingoptimizations, three of which are outlined in the paper.