TriMedia CPU64 architecture

Abstract

We present a new VLIW core as a successor to the TriMedia TM1000. The processor is targeted for embedded use in media-processing devices like DTVs and set-top boxes. Intended as a core, its design must be supplemented with on-chip co-processors to obtain a cost-effective system. Good performance is obtained through a uniform 64-bit 5 issue-slot VLIW design, supporting subword parallelism with an extensive instruction set optimized with respect to media-processing. Multi-slot 'super-ops' allow powerful multi-argument and multi-result operations. As an example, the IDCT algorithm shows a very low instruction count in comparison with other processors. To achieve good performance, critical sections in the application program source code need to be rewritten with vector data types and function calls for media operations. Benchmarking with several media applications was used to tune the instruction set and study cache behaviour. This resulted in a VLIW architecture with wide data paths and relatively simple CPU control.