diff --git a/sdk/xtdk/xtcommon.h b/sdk/xtdk/xtcommon.h
index 3ce88fe..b25615b 100644
--- a/sdk/xtdk/xtcommon.h
+++ b/sdk/xtdk/xtcommon.h
@@ -9,6 +9,7 @@
 #ifndef __XTDK_XTCOMMON_H
 #define __XTDK_XTCOMMON_H
 
+#include "xtdefs.h"
 #include "xttypes.h"
 #include "xtstruct.h"
 
@@ -43,4 +44,11 @@ typedef struct _LIST_ENTRY64
     ULONGLONG Blink;
 } LIST_ENTRY64, *PLIST_ENTRY64;
 
+/* 128-bit 16-byte aligned XMM register */
+typedef struct ALIGN(16) _M128
+{
+    ULONGLONG Low;
+    LONGLONG High;
+} M128, *PM128;
+
 #endif /* __XTDK_XTCOMMON_H */
diff --git a/sdk/xtdk/xtstruct.h b/sdk/xtdk/xtstruct.h
index d2280f4..273baa7 100644
--- a/sdk/xtdk/xtstruct.h
+++ b/sdk/xtdk/xtstruct.h
@@ -9,6 +9,8 @@
 #ifndef __XTDK_XTSTRUCT_H
 #define __XTDK_XTSTRUCT_H
 
+#include "xtdefs.h"
+
 
 /* Structures forward references */
 typedef struct _CPPORT CPPORT, *PCPPORT;
@@ -155,6 +157,7 @@ typedef struct _LIST_ENTRY32 LIST_ENTRY32, *PLIST_ENTRY32;
 typedef struct _LIST_ENTRY64 LIST_ENTRY64, *PLIST_ENTRY64;
 typedef struct _LOADER_INFORMATION_BLOCK LOADER_INFORMATION_BLOCK, *PLOADER_INFORMATION_BLOCK;
 typedef struct _LOADER_MEMORY_MAPPING LOADER_MEMORY_MAPPING, *PLOADER_MEMORY_MAPPING;
+typedef struct ALIGN(16) _M128 M128, *PM128;
 typedef struct _PCAT_FIRMWARE_INFORMATION PCAT_FIRMWARE_INFORMATION, *PPCAT_FIRMWARE_INFORMATION;
 typedef struct _PCI_COMMON_CONFIG PCI_COMMON_CONFIG, *PPCI_COMMON_CONFIG;
 typedef struct _PCI_COMMON_HEADER PCI_COMMON_HEADER, *PPCI_COMMON_HEADER;