Abstracts Computer Science

The architecture of VIS multimedia extension

by Young-Kyong Kwon

In the past, multimedia technology focused mainly on designing high quality audio and graphical imagery as well as providing adequate performance levels that the users demand for multimedia applications. However, the concept of multimedia has expanded into New-Media that involves variety use of multimedia data in consumer-oriented applications, such as video conferencing, virtual reality, and multimedia games with 3-D effect in video and audio. As the demands for multimedia applications increase, vendors have come up with new cost-effective microprocessor designs to satisfy the complexity of new media processing. One of the most efficient methods is to incorporate the special-purpose multimedia processor into a general-purpose processor, thereby offering multimedia-related functions at a small cost. Most effective way to integrate the two different processors is to extend the existing instruction set into a multimedia-oriented Instruction Set Architecture, called Media ISA Extension. Currently, many microprocessor vendors have produced variety of general-purpose processors with multimedia extensions. This thesis aims to provide the overall design philosophy behind Media ISA Extension and its effect on the overall performance of a general-purpose processor. In particular, Sun Microsystems' Visual Instruction Set (VIS) media extension of UltraSPARC-V9 is studied. On the average, VIS provides a speed-up of 3 to 4 for various multimedia applications. This performance improvement comes from the considerable reduction in the number of instructions executed due to Single Instruction Multiple Data (SIMD) execution style of VIS media extensions. To examine how VIS improves multimedia performance, the thesis studies the design concept, benefits and limitations of VIS extensions, and the performance of various multimedia applications with and without VIS extension. Finally, the possible architectural modifications to the VIS extension for further performance enhancement are suggested.