Development of RISC-V Based Soft-core Processor with Scalable Vector Extension for Embedded System
Yoshiki Kimura, Kanemitsu Ootsu, Tatsuya Tsuchiya, Takashi Yokota · 2021
Recently, the opportunity to use FPGA in the field of embedded computer system has increased. However, the development cost using FPGA is quite high. We can reduce the cost by limiting the development of the dedicated circuit to the essenially required part of the system and by using soft-core processor together. If the performance of the soft-core processor improves, the development cost can be suppressed, since the amount of the dedicated circuit can be reduced. Furthermore, even in the field of embedded system, the opportunity for data parallel processing such as image processing is increasing. We consider that it is important merit of soft-core processor with SIMD extension that the computation performance can be optimized to the system by changing the number of parallel computing units according to the application. However, it is an obstacle that the software for soft-core processor needs to be changed every time we change the number of computing units. Thus, vector processing facility should provide the scalability that means the number of computing units can be changed without changing the program code. In this paper, we develop a RISC-V based soft-core processor with the scalable vector extension.