diff --git a/xtoskrnl/hl/x86/pic.c b/xtoskrnl/hl/x86/pic.c
index 45352f5..4123d7d 100644
--- a/xtoskrnl/hl/x86/pic.c
+++ b/xtoskrnl/hl/x86/pic.c
@@ -35,7 +35,7 @@ HlClearApicErrors(VOID)
  * @since XT 1.0
  */
 XTFASTCALL
-ULONG
+ULONGLONG
 HlReadApicRegister(IN APIC_REGISTER Register)
 {
     if(HlpApicMode == APIC_MODE_X2APIC)
@@ -81,7 +81,7 @@ HlSendEoi(VOID)
 XTFASTCALL
 VOID
 HlWriteApicRegister(IN APIC_REGISTER Register,
-                    IN ULONG Value)
+                    IN ULONGLONG Value)
 {
     if(HlpApicMode == APIC_MODE_X2APIC)
     {
diff --git a/xtoskrnl/includes/amd64/hli.h b/xtoskrnl/includes/amd64/hli.h
index 7eaf716..6c61d5b 100644
--- a/xtoskrnl/includes/amd64/hli.h
+++ b/xtoskrnl/includes/amd64/hli.h
@@ -18,7 +18,7 @@ VOID
 HlClearApicErrors(VOID);
 
 XTFASTCALL
-ULONG
+ULONGLONG
 HlReadApicRegister(IN APIC_REGISTER Register);
 
 XTAPI
@@ -28,7 +28,7 @@ HlSendEoi(VOID);
 XTFASTCALL
 VOID
 HlWriteApicRegister(IN APIC_REGISTER Register,
-                    IN ULONG Value);
+                    IN ULONGLONG Value);
 
 XTAPI
 BOOLEAN
diff --git a/xtoskrnl/includes/i686/hli.h b/xtoskrnl/includes/i686/hli.h
index f6460e4..5b8024f 100644
--- a/xtoskrnl/includes/i686/hli.h
+++ b/xtoskrnl/includes/i686/hli.h
@@ -18,7 +18,7 @@ VOID
 HlClearApicErrors(VOID);
 
 XTFASTCALL
-ULONG
+ULONGLONG
 HlReadApicRegister(IN APIC_REGISTER Register);
 
 XTAPI
@@ -28,7 +28,7 @@ HlSendEoi(VOID);
 XTFASTCALL
 VOID
 HlWriteApicRegister(IN APIC_REGISTER Register,
-                    IN ULONG Value);
+                    IN ULONGLONG Value);
 
 XTAPI
 BOOLEAN