RVCoreP-32IC: An optimized RISC- V soft processor supporting the compressed instructions

The compressed instructions extension in RISC-V reduces the program size. However, it needs a complicated logic for the instruction fetch unit and has an impact on performance. In this paper, we propose an instruction fetch unit that supports the compressed instructions achieving high performance. Furthermore, we propose a RISC-V soft processor using this unit. We implement this proposed processor in Verilog HDL and verify the behavior using Verilog simulation and a Xilinx Artix-7 FPGA board. We compare the results of some benchmarks and the amount of hardware with related works. From the evaluation results, we show that the proposed processor achieves 42.5% performance improvement compared with VexRiscv, which is a high-performance and open source RV32IC processor.