A Ubiquitous Processor Built-in a Waved Multifunctional Unit

Abstract

In developing cutting edge VLSI processors, parallelism is one of the most important global standard strategies to achieve power conscious high performance. These features are more critical for ubiquitous systems with great demands for multimedia mobile processing. Then, one of most important issues for ubiquitous systems is instruction scheduling, because floating point units indispensable for multimedia mobile applications take longer latency than integer units. Although software parallelism has been inevitable to fully utilize hardware parallelism between regular scalar units, it has been really awkward. Thus, we describe in this article a double scheme to achieve instruction scheduling free ILP (instruction level parallelism) and apply the double scheme to a ubiquitous processor HCgorilla we have so far developed. The double scheme is the multifunctionalization of scalar units and making a resultant multifunctional unit (MFU) wave-pipeline. The multifunctionalization frees the instruction scheduling, and the wave-pipelining recovers the reduction of clock speed to be caused by the scale up of a multifunctional circuit. HCgorilla built-in the waved MFU is promising for wide-range dynamic ILP at a rate higher than regular processors.