Agile Design of a RISC-V Processor with Trigonometric Math Extensions Using SpinalHDL

The purpose of hardware agile design is to speed up chip prototype verification and shorten the design cycle. The key of it is higher hardware description level, more flexible design reuse and faster design iteration. This paper uses SpinalHDL to design a five-stage pipeline RISC-V processor and expands five trigonometric math instructions based on the CORDIC algorithm. Using SpinalHDL offers a shorter design cycle and better processor configurability. The resource of processor is evaluated on Xilinx Kintex-7 XC7K325T-2FFG900C and the precision of the extended instruction is evaluated. Compared with the unextended processor, the consumption of LUTs and Registers of the extended processor increases by 53.20% and 19.97% respectively. These functions achieve an average 382× speedup in execution cycles when implemented using extended instructions instead of the standard math library.