设计的CPU能执行RISC-V精简指令集: S1={sb, sh, sw, lb, lh, lw, lbu, lhu}，S2={add，sub，xor, or, and, srl, sra, sll}，S3={xori, ori, andi, srli, srai, slli}，S4={slt, sltu, slti, sltiu}，S5={jal, jalr}，S6={beq, bne, blt