diff --git a/src/assembler.h b/src/assembler.h
index f84dd37b34..e97ee597db 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -153,8 +153,6 @@ class Assembler {
   virtual unsigned argumentRegisterCount() = 0;
   virtual int argumentRegister(unsigned index) = 0;
 
-  virtual int stackSyncRegister(unsigned index) = 0;
-
   virtual void getTargets(UnaryOperation op, unsigned size,
                           Register* a) = 0;
 
diff --git a/src/x86.cpp b/src/x86.cpp
index 8f57f259b6..508d4ebd7b 100644
--- a/src/x86.cpp
+++ b/src/x86.cpp
@@ -872,6 +872,17 @@ andCM(Context* c, unsigned size UNUSED, Assembler::Constant* a,
   }
 }
 
+void
+xorRR(Context* c, unsigned size UNUSED, Assembler::Register* a,
+      Assembler::Register* b)
+{
+  assert(c, BytesPerWord == 8 or size == 4); // todo
+
+  rex(c);
+  c->code.append(0x31);
+  c->code.append(0xc0 | (a->low << 3) | b->low);
+}
+
 void
 shiftLeftCR(Context* c, unsigned size UNUSED, Assembler::Constant* a,
             Assembler::Register* b)
@@ -1047,6 +1058,8 @@ populateTables()
   BinaryOperations[INDEX2(And, Constant, Register)] = CAST2(andCR);
   BinaryOperations[INDEX2(And, Constant, Memory)] = CAST2(andCM);
 
+  BinaryOperations[INDEX2(Xor, Register, Register)] = CAST2(xorRR);
+
   BinaryOperations[INDEX2(ShiftLeft, Constant, Register)] = CAST2(shiftLeftCR);
 
   BinaryOperations[INDEX2(Subtract, Constant, Register)] = CAST2(subtractCR);
@@ -1124,23 +1137,6 @@ class MyAssembler: public Assembler {
     }
   }
 
-  virtual int stackSyncRegister(unsigned index) {
-    switch (index) {
-    case 0:
-      return rax;
-    case 1:
-      return rcx;
-    case 2:
-      return rdx;
-    case 3:
-      return rsi;
-    case 4:
-      return rdi;
-    default:
-      abort(&c);
-    }
-  }
-
   virtual void getTargets(UnaryOperation /*op*/, unsigned /*size*/,
                           Register* r)
   {