diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 36435b0c..afcf5839 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -88,6 +88,7 @@ if (ARCHITECTURE_x86_64)
          backend_x64/emit_x64.h
          backend_x64/hostloc.h
          backend_x64/jitstate.h
+         backend_x64/oparg.h
          backend_x64/reg_alloc.h
          )
 
diff --git a/src/backend_x64/oparg.h b/src/backend_x64/oparg.h
new file mode 100644
index 00000000..cc98f049
--- /dev/null
+++ b/src/backend_x64/oparg.h
@@ -0,0 +1,80 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2016 MerryMage
+ * This software may be used and distributed according to the terms of the GNU
+ * General Public License version 2 or any later version.
+ */
+
+#pragma once
+
+#include <xbyak.h>
+
+#include "common/assert.h"
+
+namespace Dynarmic {
+namespace BackendX64 {
+
+struct OpArg {
+    OpArg() : type(Type::Operand), inner_operand() {}
+    /* implicit */ OpArg(const Xbyak::Address& address) : type(Type::Address), inner_address(address) {}
+    /* implicit */ OpArg(const Xbyak::Reg& reg) : type(Type::Reg), inner_reg(reg) {}
+
+    Xbyak::Operand& operator*() {
+        switch (type) {
+        case Type::Address:
+            return inner_address;
+        case Type::Operand:
+            return inner_operand;
+        case Type::Reg:
+            return inner_reg;
+        }
+        ASSERT_MSG(false, "Unreachable");
+    }
+
+    void setBit(int bits) {
+        switch (type) {
+        case Type::Address:
+            inner_address.setBit(bits);
+            return;
+        case Type::Operand:
+            inner_operand.setBit(bits);
+            return;
+        case Type::Reg:
+            switch (bits) {
+            case 8:
+                inner_reg = inner_reg.cvt8();
+                return;
+            case 16:
+                inner_reg = inner_reg.cvt16();
+                return;
+            case 32:
+                inner_reg = inner_reg.cvt32();
+                return;
+            case 64:
+                inner_reg = inner_reg.cvt64();
+                return;
+            default:
+                ASSERT_MSG(false, "Invalid bits");
+                return;
+            }
+        }
+        ASSERT_MSG(false, "Unreachable");
+    }
+
+private:
+    enum class Type {
+        Operand,
+        Address,
+        Reg,
+    };
+
+    Type type;
+
+    union {
+        Xbyak::Operand inner_operand;
+        Xbyak::Address inner_address;
+        Xbyak::Reg inner_reg;
+    };
+};
+
+} // namespace BackendX64
+} // namespace Dynarmic
diff --git a/src/backend_x64/reg_alloc.h b/src/backend_x64/reg_alloc.h
index c4f0b642..d2e69b62 100644
--- a/src/backend_x64/reg_alloc.h
+++ b/src/backend_x64/reg_alloc.h
@@ -14,6 +14,7 @@
 
 #include "backend_x64/block_of_code.h"
 #include "backend_x64/hostloc.h"
+#include "backend_x64/oparg.h"
 #include "common/common_types.h"
 #include "frontend/ir/microinstruction.h"
 #include "frontend/ir/value.h"
@@ -21,69 +22,6 @@
 namespace Dynarmic {
 namespace BackendX64 {
 
-struct OpArg {
-    OpArg() : type(Type::Operand), inner_operand() {}
-    /* implicit */ OpArg(const Xbyak::Address& address) : type(Type::Address), inner_address(address) {}
-    /* implicit */ OpArg(const Xbyak::Reg& reg) : type(Type::Reg), inner_reg(reg) {}
-
-    Xbyak::Operand& operator*() {
-        switch (type) {
-        case Type::Address:
-            return inner_address;
-        case Type::Operand:
-            return inner_operand;
-        case Type::Reg:
-            return inner_reg;
-        }
-        ASSERT_MSG(false, "Unreachable");
-    }
-
-    void setBit(int bits) {
-        switch (type) {
-        case Type::Address:
-            inner_address.setBit(bits);
-            return;
-        case Type::Operand:
-            inner_operand.setBit(bits);
-            return;
-        case Type::Reg:
-            switch (bits) {
-            case 8:
-                inner_reg = inner_reg.cvt8();
-                return;
-            case 16:
-                inner_reg = inner_reg.cvt16();
-                return;
-            case 32:
-                inner_reg = inner_reg.cvt32();
-                return;
-            case 64:
-                inner_reg = inner_reg.cvt64();
-                return;
-            default:
-                ASSERT_MSG(false, "Invalid bits");
-                return;
-            }
-        }
-        ASSERT_MSG(false, "Unreachable");
-    }
-
-private:
-    enum class Type {
-        Operand,
-        Address,
-        Reg,
-    };
-
-    Type type;
-
-    union {
-        Xbyak::Operand inner_operand;
-        Xbyak::Address inner_address;
-        Xbyak::Reg inner_reg;
-    };
-};
-
 class RegAlloc final {
 public:
     explicit RegAlloc(BlockOfCode* code) : code(code) {}