Add SRAIW instruction

rvfi/insns/insn_sraiw.py

@@ -0,0 +1,17 @@
+from .insn_rv64i_i_type_shift import *
+
+"""
+SRAIW instruction
+"""
+
+class InsnSraiw(InsnRV64IITypeShift):
+    def __init__(self, params):
+        super().__init__(params, 0b010000, 0b101)
+    def elaborate(self, platform):
+        m = super().elaborate(platform)
+
+        result = Signal(32)
+        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
+        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))
+
+        return m