: Processors used in portable systems must provide highly energy-efficient operation, due to the importance of battery weight and size, without compromising high performance when the user requires it. The user-dependent modes of operation of a processor in portable systems are described and separate metrics for energy efficiency for each of them are found to be required. A variety of well known low-power techniques are re-evaluated against these metrics and in some cases are not found to be appropriate leading to a set of energy-efficient design principles. Also, the importance of idle energy reduction and the joint optimization of hardware and software will be examined for achieving the ultimate in lowenergy, high-performance design. 1. Introduction The recent explosive growth in portable electronics requires energy conscious design, without sacrificing performance. Simply increasing the battery capacity is not sufficient because the battery has become a significant fraction of the t...

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Design guidelines for low- and ultra low-power arithmetic units are presented. We analyze structures for addition in the energy-delay space to determine the most suitable for these regions of operations. This paper demonstrates that the use of more complex highperformance structures combined with scaling of the supply-voltage outperforms traditional low-power oriented designs in the low- and ultra low-power domain. 1.

■ Text/Graphics display ■ Video decompression ■ Full-motion video display How to get 8 hours of operation???