Exploiting Narrow Bitwidth Operations for Low Power Embedded Software Design

This paper proposes a low power software design technique for processor-based embedded systems. A basic idea is to reduce switching activities in sign extension bits of instruction operands through shifting the operands. To the best of our knowledge, this is the first software-level power reduction technique which exploits narrow bitwidth operations. Our technique, called shifted operation technique in this paper, consists of following three steps: 1) shift operands from LSB side toward MSB side by optimal shift amount, 2) execute instructions with the shifted operands, and 3) shift back computational results to original positions. Experimental results exploiting shifted operation technique show about 10.7% energy reduction of datapath, and about 5.5% energy reduction of overall processor