-#define DXE_SERVICES_SIGNATURE 0x565245535f455844ULL\r
-#define DXE_SERVICES_REVISION ((1<<16) | (00))\r
+#define DXE_SERVICES_SIGNATURE 0x565245535f455844ULL\r
+#define DXE_SPECIFICATION_MAJOR_REVISION 1\r
+#define DXE_SPECIFICATION_MINOR_REVISION 20\r
+#define DXE_SERVICES_REVISION ((DXE_SPECIFICATION_MAJOR_REVISION<<16) | (DXE_SPECIFICATION_MINOR_REVISION))\r