from InsnRV32IRType import *

"""
SRA instruction
"""

class InsnSra(InsnRV32IRType):
    def __init__(self, RISCV_FORMAL_ILEN, RISCV_FORMAL_XLEN, RISCV_FORMAL_CSR_MISA):
        super().__init__(RISCV_FORMAL_ILEN, RISCV_FORMAL_XLEN, RISCV_FORMAL_CSR_MISA, 0b0100000, 0b101, 0b0110011)
    def elaborate(self, platform):
        m = super().elaborate(platform)

        m.d.comb += self.spec_rd_wdata.eq(Mux(self.spec_rd_addr, (Value.as_signed(self.rvfi_rs1_rdata) >> Mux(self.RISCV_FORMAL_XLEN == 64, self.rvfi_rs2_rdata[:6], self.rvfi_rs2_rdata[:5])) | (-(Value.as_signed(self.rvfi_rs1_rdata) < 0) << (self.RISCV_FORMAL_XLEN - Mux(self.RISCV_FORMAL_XLEN == 64, self.rvfi_rs2_rdata[:6], self.rvfi_rs2_rdata[:5]))), 0)) # https://stackoverflow.com/a/25207042

        return m