diff --git a/src/arch/x86/isa/microops/regop.isa b/src/arch/x86/isa/microops/regop.isa
index f833f89be..a0e8adc9a 100644
--- a/src/arch/x86/isa/microops/regop.isa
+++ b/src/arch/x86/isa/microops/regop.isa
@@ -309,7 +309,7 @@ let {{
     exec_output = ""
 
     # A function which builds the C++ classes that implement the microops
-    def setUpMicroRegOp(name, Name, base, code, flagCode, condCheck, elseCode):
+    def setUpMicroRegOp(name, Name, base, code, flagCode = "", condCheck = "true", elseCode = ";"):
         global header_output
         global decoder_output
         global exec_output
@@ -331,7 +331,7 @@ let {{
 
     # This creates a python representations of a microop which are a cross
     # product of reg/immediate and flag/no flag versions.
-    def defineMicroRegOp(mnemonic, code, secondSrc = "op2", cc=False, elseCode=";"):
+    def defineMicroRegOp(mnemonic, code, subtract = False, cc=False, elseCode=";"):
         Name = mnemonic
         name = mnemonic.lower()
 
@@ -342,6 +342,11 @@ let {{
         regCode = matcher.sub("SrcReg2", code)
         immCode = matcher.sub("imm8", code)
 
+        if subtract:
+            secondSrc = "-op2, true"
+        else:
+            secondSrc = "op2"
+
         if not cc:
             flagCode = genCCFlagBits % secondSrc
             condCode = "true"
@@ -360,8 +365,9 @@ let {{
 
         microopClasses[name] = RegOpChild
 
-        setUpMicroRegOp(name, Name, "X86ISA::RegOp", regCode, "", "true", elseCode);
-        setUpMicroRegOp(name, Name + "Flags", "X86ISA::RegOp", regCode, regFlagCode, condCode, elseCode);
+        setUpMicroRegOp(name, Name, "X86ISA::RegOp", regCode);
+        setUpMicroRegOp(name, Name + "Flags", "X86ISA::RegOp", regCode,
+                flagCode = regFlagCode, condCheck = condCode, elseCode = elseCode);
 
         class RegOpChildImm(RegOpImm):
             mnemonic = name + 'i'
@@ -371,17 +377,19 @@ let {{
 
         microopClasses[name + 'i'] = RegOpChildImm
 
-        setUpMicroRegOp(name + "i", Name + "Imm", "X86ISA::RegOpImm", immCode, "", "true", elseCode);
-        setUpMicroRegOp(name + "i", Name + "ImmFlags", "X86ISA::RegOpImm", immCode, immFlagCode, condCode, elseCode);
+        setUpMicroRegOp(name + "i", Name + "Imm", "X86ISA::RegOpImm", immCode);
+        setUpMicroRegOp(name + "i", Name + "ImmFlags", "X86ISA::RegOpImm", immCode,
+                flagCode = immFlagCode, condCheck = condCode, elseCode = elseCode);
 
     defineMicroRegOp('Add', 'DestReg = merge(DestReg, SrcReg1 + op2, dataSize)')
     defineMicroRegOp('Or', 'DestReg = merge(DestReg, SrcReg1 | op2, dataSize)')
     defineMicroRegOp('Adc', 'DestReg = merge(DestReg, SrcReg1 + op2, dataSize)')
-    defineMicroRegOp('Sbb', 'DestReg = merge(DestReg, SrcReg1 - op2, dataSize)', '-op2')
+    defineMicroRegOp('Sbb', 'DestReg = merge(DestReg, SrcReg1 - op2, dataSize)', True)
     defineMicroRegOp('And', 'DestReg = merge(DestReg, SrcReg1 & op2, dataSize)')
-    defineMicroRegOp('Sub', 'DestReg = merge(DestReg, SrcReg1 - op2, dataSize)', '-op2')
+    defineMicroRegOp('Sub', 'DestReg = merge(DestReg, SrcReg1 - op2, dataSize)', True)
     defineMicroRegOp('Xor', 'DestReg = merge(DestReg, SrcReg1 ^ op2, dataSize)')
-    defineMicroRegOp('Cmp', 'DestReg = merge(DestReg, DestReg - op2, dataSize)', '-op2')
+    defineMicroRegOp('Cmp', 'DestReg = merge(DestReg, DestReg - op2, dataSize)', True)
+    defineMicroRegOp('mul1s', 'DestReg = merge(DestReg, DestReg * op2, dataSize)')
     defineMicroRegOp('Mov', 'DestReg = merge(SrcReg1, op2, dataSize)',
             elseCode='DestReg=DestReg;', cc=True)
 
@@ -405,8 +413,9 @@ let {{
 
         microopClasses[name] = RegOpChild
 
-        setUpMicroRegOp(name, Name, "X86ISA::RegOp", regCode, "", "true", elseCode);
-        setUpMicroRegOp(name, Name + "Flags", "X86ISA::RegOp", regCode, "", checkCCFlagBits, elseCode);
+        setUpMicroRegOp(name, Name, "X86ISA::RegOp", regCode);
+        setUpMicroRegOp(name, Name + "Flags", "X86ISA::RegOp", regCode,
+                condCheck = checkCCFlagBits, elseCode = elseCode);
 
         class RegOpChildImm(RegOpImm):
             mnemonic = name + 'i'
@@ -416,8 +425,9 @@ let {{
 
         microopClasses[name + 'i'] = RegOpChildImm
 
-        setUpMicroRegOp(name + 'i', Name + "Imm", "X86ISA::RegOpImm", immCode, "", "true", elseCode);
-        setUpMicroRegOp(name + 'i', Name + "ImmFlags", "X86ISA::RegOpImm", immCode, "", checkCCFlagBits, elseCode);
+        setUpMicroRegOp(name + 'i', Name + "Imm", "X86ISA::RegOpImm", immCode);
+        setUpMicroRegOp(name + 'i', Name + "ImmFlags", "X86ISA::RegOpImm", immCode,
+                condCheck = checkCCFlagBits, elseCode = elseCode);
 
     defineMicroRegOpWr('Wrip', 'RIP = SrcReg1 + op2', elseCode="RIP = RIP;")
 
@@ -434,7 +444,7 @@ let {{
 
         microopClasses[name] = RegOpChild
 
-        setUpMicroRegOp(name, Name, "X86ISA::RegOp", code, "", "true", ";");
+        setUpMicroRegOp(name, Name, "X86ISA::RegOp", code);
 
     defineMicroRegOpRd('Rdip', 'DestReg = RIP')
 
@@ -450,11 +460,13 @@ let {{
 
         microopClasses[name] = RegOpChild
 
-        setUpMicroRegOp(name, Name, "X86ISA::RegOpImm", code, "", "true", ";");
+        setUpMicroRegOp(name, Name, "X86ISA::RegOpImm", code);
 
     defineMicroRegOpImm('Sext', '''
             IntReg val = SrcReg1;
             int sign_bit = bits(val, imm8-1, imm8-1);
             val = sign_bit ? (val | ~mask(imm8)) : val;
             DestReg = merge(DestReg, val, dataSize);''')
+
+    defineMicroRegOpImm('Zext', 'DestReg = bits(SrcReg1, imm8-1, 0);')
 }};