diff --git a/reactos/include/ntos/types.h b/reactos/include/ntos/types.h
index 297ec7d12a7..1c296742ba0 100644
--- a/reactos/include/ntos/types.h
+++ b/reactos/include/ntos/types.h
@@ -269,12 +269,15 @@ typedef unsigned short *PRTL_ATOM;
 
 #ifndef __USE_W32API
 
-#define CONTEXT_CONTROL         (CONTEXT_i386 | 1)
-#define CONTEXT_INTEGER         (CONTEXT_i386 | 2)
-#define CONTEXT_SEGMENTS        (CONTEXT_i386 | 4)
-#define CONTEXT_FLOATING_POINT  (CONTEXT_i386 | 8)
-#define CONTEXT_DEBUG_REGISTERS (CONTEXT_i386 | 0x10)
-#define CONTEXT_FULL (CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS)
+#define CONTEXT_CONTROL            (CONTEXT_i386 | 1)
+#define CONTEXT_INTEGER            (CONTEXT_i386 | 2)
+#define CONTEXT_SEGMENTS           (CONTEXT_i386 | 4)
+#define CONTEXT_FLOATING_POINT     (CONTEXT_i386 | 8)
+#define CONTEXT_DEBUG_REGISTERS    (CONTEXT_i386 | 0x10)
+#define CONTEXT_EXTENDED_REGISTERS (CONTEXT_i386 | 0x20)
+#define CONTEXT_FULL               (CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS)
+
+#define MAXIMUM_SUPPORTED_EXTENSION  512
 
 #endif /* !__USE_W32API */
 
@@ -315,6 +318,8 @@ typedef struct _CONTEXT_X86
   DWORD   EFlags;
   DWORD   Esp;
   DWORD   SegSs;
+
+  BYTE    ExtendedRegisters[MAXIMUM_SUPPORTED_EXTENSION];
 } CONTEXT_X86, *PCONTEXT_X86, *LPCONTEXT_X86;
 
 typedef struct _CONTEXT_PPC