diff --git a/insns/insn_srai.py b/insns/insn_srai.py new file mode 100644 index 0000000..a9c4efb --- /dev/null +++ b/insns/insn_srai.py @@ -0,0 +1,86 @@ +from nmigen import * + +class rvfi_insn_srai(Elaboratable): + def __init__(self, RISCV_FORMAL_ILEN=32, RISCV_FORMAL_XLEN=32): + self.RISCV_FORMAL_ILEN = RISCV_FORMAL_ILEN + self.RISCV_FORMAL_XLEN = RISCV_FORMAL_XLEN + self.rvfi_valid = Signal(1) + self.rvfi_insn = Signal(self.RISCV_FORMAL_ILEN) + self.rvfi_pc_rdata = Signal(self.RISCV_FORMAL_XLEN) + self.rvfi_rs1_rdata = Signal(self.RISCV_FORMAL_XLEN) + self.rvfi_rs2_rdata = Signal(self.RISCV_FORMAL_XLEN) + self.rvfi_mem_rdata = Signal(self.RISCV_FORMAL_XLEN) + self.spec_valid = Signal(1) + self.spec_trap = Signal(1) + self.spec_rs1_addr = Signal(5) + self.spec_rs2_addr = Signal(5) + self.spec_rd_addr = Signal(5) + self.spec_rd_wdata = Signal(self.RISCV_FORMAL_XLEN) + self.spec_pc_wdata = Signal(self.RISCV_FORMAL_XLEN) + self.spec_mem_addr = Signal(self.RISCV_FORMAL_XLEN) + self.spec_mem_rmask = Signal(int(self.RISCV_FORMAL_XLEN // 8)) + self.spec_mem_wmask = Signal(int(self.RISCV_FORMAL_XLEN // 8)) + self.spec_mem_wdata = Signal(self.RISCV_FORMAL_XLEN) + def ports(self): + input_ports = [ + self.rvfi_valid, + self.rvfi_insn, + self.rvfi_pc_rdata, + self.rvfi_rs1_rdata, + self.rvfi_rs2_rdata, + self.rvfi_mem_rdata + ] + output_ports = [ + self.spec_valid, + self.spec_trap, + self.spec_rs1_addr, + self.spec_rs2_addr, + self.spec_rd_addr, + self.spec_rd_wdata, + self.spec_pc_wdata, + self.spec_mem_addr, + self.spec_mem_rmask, + self.spec_mem_wmask, + self.spec_mem_wdata + ] + return input_ports + output_ports + def elaborate(self, platform): + m = Module() + + # I-type instruction format (shift variation) + insn_padding = Signal(self.RISCV_FORMAL_ILEN) + m.d.comb += insn_padding.eq(self.rvfi_insn >> 32) + insn_funct6 = Signal(7) + m.d.comb += insn_funct6.eq(self.rvfi_insn[26:32]) + insn_shamt = Signal(6) + m.d.comb += insn_shamt.eq(self.rvfi_insn[20:26]) + insn_rs1 = Signal(5) + m.d.comb += insn_rs1.eq(self.rvfi_insn[15:20]) + insn_funct3 = Signal(3) + m.d.comb += insn_funct3.eq(self.rvfi_insn[12:15]) + insn_rd = Signal(5) + m.d.comb += insn_rd.eq(self.rvfi_insn[7:12]) + insn_opcode = Signal(7) + m.d.comb += insn_opcode.eq(self.rvfi_insn[:7]) + + misa_ok = Signal(1) + m.d.comb += misa_ok.eq(1) + + # SRAI instruction + result = Signal(self.RISCV_FORMAL_XLEN) + m.d.comb += result.eq((self.rvfi_rs1_rdata >> insn_shamt) | (-(self.rvfi_rs1_rdata < 0) << (self.RISCV_FORMAL_XLEN - insn_shamt))) # https://stackoverflow.com/a/25207042 + m.d.comb += self.spec_valid.eq(self.rvfi_valid & (~insn_padding) & (insn_funct6 == 0b010000) & (insn_funct3 == 0b101) & (insn_opcode == 0b0010011) & ((~insn_shamt[5]) | (self.RISCV_FORMAL_XLEN == 64))) + m.d.comb += self.spec_rs1_addr.eq(insn_rs1) + m.d.comb += self.spec_rd_addr.eq(insn_rd) + m.d.comb += self.spec_rd_wdata.eq(Mux(self.spec_rd_addr, result, 0)) + m.d.comb += self.spec_pc_wdata.eq(self.rvfi_pc_rdata + 4) + + # default assignments + m.d.comb += self.spec_rs2_addr.eq(0) + m.d.comb += self.spec_trap.eq(~misa_ok) + m.d.comb += self.spec_mem_addr.eq(0) + m.d.comb += self.spec_mem_rmask.eq(0) + m.d.comb += self.spec_mem_wmask.eq(0) + m.d.comb += self.spec_mem_wdata.eq(0) + + return m