Hardware/software co-design of a fuzzy RISC processor

In this paper, we show how hardware/software co-evaluation can be applied to instruction set definition. As a case study, we show the definition and evaluation of instruction set extensions for fuzzy processing. These instructions are based on the use of subword parallelism to fully exploit the processor's resources by processing multiple data streams in parallel. The proposed instructions are evaluated in software and hardware to gain a balanced view of the costs and benefits of each instruction. We have found that a simple instruction optimized to perform fuzzy rule evaluation offers the most benefit to improve fuzzy processing performance. The instruction set extensions are added to a RISC processor core based on the MIPS instruction set architecture. The core has been described in VHDL so that hardware implementations can be generated using logic synthesis.