diff --git a/config.h b/config.h
index a0b98e69..1089c11c 100644
--- a/config.h
+++ b/config.h
@@ -182,7 +182,7 @@ NAMESPACE_END
 #endif
 
 // CodeWarrior defines _MSC_VER
-#if !defined(CRYPTOPP_DISABLE_X86ASM) && (defined(_MSC_VER) && !defined(__MWERKS__) && defined(_M_IX86)) || (defined(__GNUC__) && defined(__i386__))
+#if !defined(CRYPTOPP_DISABLE_X86ASM) && ((defined(_MSC_VER) && !defined(__MWERKS__) && defined(_M_IX86)) || (defined(__GNUC__) && defined(__i386__)))
 #define CRYPTOPP_X86ASM_AVAILABLE
 #endif