diff --git a/sdk/xtdk/amd64/rtltypes.h b/sdk/xtdk/amd64/rtltypes.h
new file mode 100644
index 0000000..fbba3e2
--- /dev/null
+++ b/sdk/xtdk/amd64/rtltypes.h
@@ -0,0 +1,27 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            sdk/xtdk/amd64/rtltypes.h
+ * DESCRIPTION:     Runtime library structures definitions for AMD64 architecture
+ * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
+ */
+
+#ifndef __XTDK_AMD64_RTLTYPES_H
+#define __XTDK_AMD64_RTLTYPES_H
+
+#include <xtbase.h>
+#include <rtltypes.h>
+
+
+/* C/C++ specific code */
+#ifndef __XTOS_ASSEMBLER__
+
+/* Header for a sequenced single linked list structure definition */
+typedef struct _SINGLE_LIST_HEADER
+{
+    ULONGLONG Alignment;
+    ULONGLONG Region;
+} SINGLE_LIST_HEADER, *PSINGLE_LIST_HEADER;
+
+#endif /* __XTOS_ASSEMBLER__ */
+#endif /* __XTDK_AMD64_RTLTYPES_H */
diff --git a/sdk/xtdk/amd64/xtstruct.h b/sdk/xtdk/amd64/xtstruct.h
index 41975a1..105eeb9 100644
--- a/sdk/xtdk/amd64/xtstruct.h
+++ b/sdk/xtdk/amd64/xtstruct.h
@@ -72,6 +72,7 @@ typedef struct _MMPTE_SOFTWARE MMPTE_SOFTWARE, *PMMPTE_SOFTWARE;
 typedef struct _MMPTE_SUBSECTION MMPTE_SUBSECTION, *PMMPTE_SUBSECTION;
 typedef struct _MMPTE_TRANSITION MMPTE_TRANSITION, *PMMPTE_TRANSITION;
 typedef struct _POOL_DESCRIPTOR POOL_DESCRIPTOR, *PPOOL_DESCRIPTOR;
+typedef struct _SINGLE_LIST_HEADER SINGLE_LIST_HEADER, *PSINGLE_LIST_HEADER;
 typedef struct _THREAD_ENVIRONMENT_BLOCK THREAD_ENVIRONMENT_BLOCK, *PTHREAD_ENVIRONMENT_BLOCK;
 typedef struct _TIMER_CAPABILITIES TIMER_CAPABILITIES, *PTIMER_CAPABILITIES;
 
diff --git a/sdk/xtdk/i686/rtltypes.h b/sdk/xtdk/i686/rtltypes.h
new file mode 100644
index 0000000..ed7a93a
--- /dev/null
+++ b/sdk/xtdk/i686/rtltypes.h
@@ -0,0 +1,32 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            sdk/xtdk/amd64/rtltypes.h
+ * DESCRIPTION:     Runtime library structures definitions for i686 architecture
+ * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
+ */
+
+#ifndef __XTDK_I686_RTLTYPES_H
+#define __XTDK_I686_RTLTYPES_H
+
+#include <xtbase.h>
+#include <rtltypes.h>
+
+
+/* C/C++ specific code */
+#ifndef __XTOS_ASSEMBLER__
+
+/* Header for a sequenced single linked list union definition */
+typedef union _SINGLE_LIST_HEADER
+{
+    ULONGLONG Alignment;
+    struct
+    {
+        SINGLE_LIST_ENTRY Next;
+        USHORT Depth;
+        USHORT Sequence;
+    };
+} SINGLE_LIST_HEADER, *PSINGLE_LIST_HEADER;
+
+#endif /* __XTOS_ASSEMBLER__ */
+#endif /* __XTDK_I686_RTLTYPES_H */
diff --git a/sdk/xtdk/i686/xtstruct.h b/sdk/xtdk/i686/xtstruct.h
index eb12ff2..8fdadb8 100644
--- a/sdk/xtdk/i686/xtstruct.h
+++ b/sdk/xtdk/i686/xtstruct.h
@@ -100,6 +100,7 @@ typedef union _PIC_I8259_ICW1 PIC_I8259_ICW1, *PPIC_I8259_ICW1;
 typedef union _PIC_I8259_ICW2 PIC_I8259_ICW2, *PPIC_I8259_ICW2;
 typedef union _PIC_I8259_ICW3 PIC_I8259_ICW3, *PPIC_I8259_ICW3;
 typedef union _PIC_I8259_ICW4 PIC_I8259_ICW4, *PPIC_I8259_ICW4;
+typedef union _SINGLE_LIST_HEADER SINGLE_LIST_HEADER, *PSINGLE_LIST_HEADER;
 
 #endif /* __XTOS_ASSEMBLER__ */
 #endif /* __XTDK_I686_XTSTRUCT_H */
diff --git a/sdk/xtdk/ketypes.h b/sdk/xtdk/ketypes.h
index 4171f9c..3e5cdaf 100644
--- a/sdk/xtdk/ketypes.h
+++ b/sdk/xtdk/ketypes.h
@@ -13,8 +13,8 @@
 #include <xtstruct.h>
 #include <xttarget.h>
 #include <xttypes.h>
-#include <rtltypes.h>
 #include ARCH_HEADER(xtstruct.h)
+#include ARCH_HEADER(rtltypes.h)
 
 
 /* Exception types and handling mechanisms */
diff --git a/sdk/xtdk/rtltypes.h b/sdk/xtdk/rtltypes.h
index 5e955d8..b0aa9d8 100644
--- a/sdk/xtdk/rtltypes.h
+++ b/sdk/xtdk/rtltypes.h
@@ -185,18 +185,6 @@ typedef struct _SINGLE_LIST_ENTRY
     PSINGLE_LIST_ENTRY Next;
 } SINGLE_LIST_ENTRY, *PSINGLE_LIST_ENTRY;
 
-/* Header for a sequenced single linked list union definition */
-typedef union _SINGLE_LIST_HEADER
-{
-    ULONGLONG Alignment;
-    struct
-    {
-        SINGLE_LIST_ENTRY Next;
-        USHORT Depth;
-        USHORT Sequence;
-    };
-} SINGLE_LIST_HEADER, *PSINGLE_LIST_HEADER;
-
 /* Runtime time fields structure definition */
 typedef struct _TIME_FIELDS
 {
diff --git a/sdk/xtdk/xtkmapi.h b/sdk/xtdk/xtkmapi.h
index 0d82e1c..142a21a 100644
--- a/sdk/xtdk/xtkmapi.h
+++ b/sdk/xtdk/xtkmapi.h
@@ -44,6 +44,7 @@
 #include ARCH_HEADER(hltypes.h)
 #include ARCH_HEADER(ketypes.h)
 #include ARCH_HEADER(mmtypes.h)
+#include ARCH_HEADER(rtltypes.h)
 
 /* XT routines */
 #include <exfuncs.h>
diff --git a/sdk/xtdk/xtstruct.h b/sdk/xtdk/xtstruct.h
index 351d8c7..4e21fd8 100644
--- a/sdk/xtdk/xtstruct.h
+++ b/sdk/xtdk/xtstruct.h
@@ -386,7 +386,6 @@ typedef union _EFI_IP_ADDRESS EFI_IP_ADDRESS, *PEFI_IP_ADDRESS;
 typedef union _EFI_PXE_BASE_CODE_PACKET EFI_PXE_BASE_CODE_PACKET, *PEFI_PXE_BASE_CODE_PACKET;
 typedef union _EX_RUNDOWN_REFERENCE EX_RUNDOWN_REFERENCE, *PEX_RUNDOWN_REFERENCE;
 typedef union _LARGE_INTEGER LARGE_INTEGER, *PLARGE_INTEGER;
-typedef union _SINGLE_LIST_HEADER SINGLE_LIST_HEADER, *PSINGLE_LIST_HEADER;
 typedef union _ULARGE_INTEGER ULARGE_INTEGER, *PULARGE_INTEGER;
 
 #endif /* __XTOS_ASSEMBLER__ */