Reconfigurable Instruction Decoding for a Wide-Control-Word Processor

Paper in proceeding, 2011

Fine-grained control through the use of a wide control word can lead to high instruction-level parallelism, but unless compressed the words require a large memory footprint. A reconfigurable fixed-length decoding scheme can be created by taking advantage of the fact that an application only uses a subset of the datapath for its execution. We present the first complete implementation of the FlexCore processor, integrating a wide-control-word datapath with a run-time reconfigurable instruction decompressor. Our evaluation, using three different EEMBC benchmarks, shows that it is possible to reach up to 35% speedup compared to a five-stage pipelined MIPS processor, assuming the same datapath units. In addition, our VLSI implementations show that this FlexCore processor offers up to 24% higher energy efficiency than the MIPS reference processor.