riscv-formal-nmigen/rvfi/insns/insn_subw.py

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2020-08-27 15:50:30 +08:00
from .insn_rv64i_r_type import *
"""
SUBW instruction
"""
class InsnSubw(InsnRV64IRType):
def __init__(self, params):
super().__init__(params, 0b0100000, 0b000)
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def elaborate(self, platform):
m = super().elaborate(platform)
result = Signal(32)
m.d.comb += result.eq(self.rvfi_rs1_rdata[:32] - self.rvfi_rs2_rdata[:32])
m.d.comb += spec_rd_wdata.eq(Mux(self.spec_rd_addr, (Mux(result[31], 2 ** (self.params.xlen - 32) - 1, 0) << 32) | result, 0))
return m