2020-08-27 13:52:20 +08:00
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from .insn_rv64i_i_type_shift import *
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"""
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SRAIW instruction
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"""
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class InsnSraiw(InsnRV64IITypeShift):
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def __init__(self, params):
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super().__init__(params, 0b010000, 0b101)
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2020-08-28 12:30:39 +08:00
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2020-08-27 13:52:20 +08:00
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def elaborate(self, platform):
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m = super().elaborate(platform)
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result = Signal(32)
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m.d.comb += result.eq((Value.as_signed(self.rvfi_rs1_rdata[:32]) >> self.insn_shamt) | (-(Value.as_signed(self.rvfi_rs1_rdata[:32]) < 0) << (32 - self.insn_shamt))) # https://stackoverflow.com/a/25207042
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m.d.comb += self.spec_rd_wdata.eq(Mux(self.spec_rd_addr, (Mux(result[31], 2 ** (self.params.xlen - 32) - 1, 0) << 32) | result, 0))
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return m
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