from insn_I_shift import *

class rvfi_insn_srai(rvfi_insn_I_shift):
    def __init__(self):
        super(rvfi_insn_srai, self).__init__()
    def ports(self):
        return super(rvfi_insn_srai, self).ports()
    def elaborate(self, platform):
        m = super(rvfi_insn_srai, self).elaborate(platform)

        # SRAI instruction
        result = Signal(32)
        m.d.comb += result.eq((self.rvfi_rs1_rdata >> self.insn_shamt) | (-(self.rvfi_rs1_rdata < 0) << (32 - self.insn_shamt))) # https://stackoverflow.com/a/25207042
        m.d.comb += self.spec_valid.eq(self.rvfi_valid & (~self.insn_padding) & (self.insn_funct6 == 0b010000) & (self.insn_funct3 == 0b101) & (self.insn_opcode == 0b0010011) & (~self.insn_shamt[5]))
        m.d.comb += self.spec_rs1_addr.eq(self.insn_rs1)
        m.d.comb += self.spec_rd_addr.eq(self.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)

        return m