diff --git a/rvfi/insns/insn_mulh.py b/rvfi/insns/insn_mulh.py
new file mode 100644
index 0000000..0998752
--- /dev/null
+++ b/rvfi/insns/insn_mulh.py
@@ -0,0 +1,14 @@
+from .insn_rv32m_r_type import *
+
+class InsnMulh(InsnRV32MRType):
+    def __init__(self, params):
+        super().__init__(params, 0b001)
+    def elaborate(self, platform):
+        m = super().elaborate(platform)
+
+        if self.params.altops:
+            m.d.comb += self.spec_rd_wdata.eq(Mux(self.spec_rd_addr, (self.rvfi_rs1_rdata + self.rvfi_rs2_rdata) ^ 0x15d01651f6583fb7, 0))
+        else:
+            m.d.comb += self.spec_rd_wdata.eq(Mux(self.spec_rd_addr, (((Mux(self.rvfi_rs1_rdata[-1], 2 ** self.params.xlen - 1, 0) << self.params.xlen) | self.rvfi_rs1_rdata) * ((Mux(self.rvfi_rs1_rdata[-1], 2 ** self.params.xlen - 1, 0) << self.params.xlen) | self.rvfi_rs2_rdata)) >> self.params.xlen, 0))
+
+        return m