Add SUB instruction

insns/insn_sub.py

@@ -0,0 +1,21 @@
+from insn_R import *
+
+class rvfi_insn_sub(rvfi_insn_R):
+    def __init__(self):
+        super(rvfi_insn_sub, self).__init__()
+    def ports(self):
+        return super(rvfi_insn_sub, self).ports()
+    def elaborate(self, platform):
+        m = super(rvfi_insn_sub, self).elaborate(platform)
+
+        # SUB instruction
+        result = Signal(32)
+        m.d.comb += result.eq(self.rvfi_rs1_rdata - self.rvfi_rs2_rdata)
+        m.d.comb += self.spec_valid.eq(self.rvfi_valid & (~self.insn_padding) & (self.insn_funct7 == 0b0100000) & (self.insn_funct3 == 0b000) & (self.insn_opcode == 0b0110011))
+        m.d.comb += self.spec_rs1_addr.eq(self.insn_rs1)
+        m.d.comb += self.spec_rs2_addr.eq(self.insn_rs2)
+        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