diff --git a/xtoskrnl/includes/rtl/endian.hh b/xtoskrnl/includes/rtl/endian.hh
index 94adaa3..d8afcd7 100644
--- a/xtoskrnl/includes/rtl/endian.hh
+++ b/xtoskrnl/includes/rtl/endian.hh
@@ -18,9 +18,9 @@ namespace RTL
     class Endianness
     {
         public:
-            STATIC XTAPI USHORT SwapByte16(IN USHORT Source);
-            STATIC XTAPI ULONG SwapByte32(IN ULONG Source);
-            STATIC XTAPI ULONGLONG SwapByte64(IN ULONGLONG Source);
+            STATIC XTFASTCALL USHORT SwapByte16(IN USHORT Source);
+            STATIC XTFASTCALL ULONG SwapByte32(IN ULONG Source);
+            STATIC XTFASTCALL ULONGLONG SwapByte64(IN ULONGLONG Source);
     };
 }
 
diff --git a/xtoskrnl/rtl/math.cc b/xtoskrnl/rtl/math.cc
index 78e2eaa..5b2258d 100644
--- a/xtoskrnl/rtl/math.cc
+++ b/xtoskrnl/rtl/math.cc
@@ -610,7 +610,7 @@ RTL::Math::GetBaseExponent(IN DOUBLE Value,
  *
  * @since XT 1.0
  */
-XTCDECL
+XTAPI
 BOOLEAN
 RTL::Math::InfiniteDouble(IN DOUBLE Value)
 {
@@ -669,7 +669,7 @@ RTL::Math::MultiplyLargeInteger(IN LARGE_INTEGER Multiplicand,
  *
  * @since XT 1.0
  */
-XTCDECL
+XTAPI
 BOOLEAN
 RTL::Math::NanDouble(IN DOUBLE Value)
 {