一种支持SIMD指令的低功耗分裂式ALU设计

A Low Power SIMD ALU Design

在面向多媒体运算的高性能、低功耗DSP芯片MD32设计中,支持SIMD指令的分裂式、低功耗ALU设计是实现其设计目标的重要环节。该文提出了利用基于资源共享的设计思想,以超前进位加法器(Carry Look-ahead Adder)为核心构造数据处理单元,完成算术以及逻辑运算,减少了ALU模块的面积,同时均衡了不同数据通路长度,并且采用先进行数据选择,而后进行数据处理的设计原则,降低不使用模块的活动度,减少了功耗。根据Design Power分析其综合后门级实现结果,芯片面积可减少8%,功耗可减少51%。

This paper proposes the design techniques of a low power partitioned ALU used for implementation of SIMD instruction. Based on the resource-shared algorithm, the 8-bit carry lookahead adders are used to construct the ALU, manipulating the arithmetic, logic and other SIMD operations. And by using MUX-before-operation structure and balancing the delays of data paths, the unwanted activity of the ALU can be reduced greatly. According to the results analyzed by design power, the proposed methods can achieve 51% power reduction and 8% area reduction to the conventional ways.