diff --git a/include/polarssl/sha512.h b/include/polarssl/sha512.h
index 90b5e3e54..1f0c6546e 100644
--- a/include/polarssl/sha512.h
+++ b/include/polarssl/sha512.h
@@ -33,11 +33,9 @@
 #include <stddef.h>
 
 #if defined(_MSC_VER) || defined(__WATCOMC__)
-  #define UL64(x) x##ui64
   typedef unsigned __int64 uint64_t;
 #else
   #include <inttypes.h>
-  #define UL64(x) x##ULL
 #endif
 
 #define POLARSSL_ERR_SHA512_FILE_IO_ERROR              -0x007A  /**< Read/write error in file. */
diff --git a/library/sha512.c b/library/sha512.c
index 5decc8fac..2c22259cf 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -35,6 +35,12 @@
 
 #include "polarssl/sha512.h"
 
+#if defined(_MSC_VER) || defined(__WATCOMC__)
+  #define UL64(x) x##ui64
+#else
+  #define UL64(x) x##ULL
+#endif
+
 #include <string.h>
 
 #if defined(POLARSSL_FS_IO)