Non-consistent dual register files to reduce register pressure

Abstract

The continuous grow on instruction level parallelism offered by microprocessors requires a large register file and a large number of ports to access it. This paper presents the non-consistent dual register file, an alternative implementation and management of the register file. Non-consistent dual register files support the bandwidth demands and the high register requirements, penalizing neither access time nor implementation cost. The proposal is evaluated for software pipelined loops and compared against a unified register file. Empirical results show improvements on performance and a noticeable reduction of the density of memory traffic due to a reduction of the spill code. The spill code can in general increase the minimum initiation interval and decrease loop performance. Additional improvements can be obtained when the operations are scheduled having in mind the register file organization proposed.