diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index c4be197..989cfe0 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -3581,16 +3581,7 @@
     diff |= peer_pms[1] ^ ver[1];
 
     /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
-    /* MSVC has a warning about unary minus on unsigned, but this is
-     * well-defined and precisely what we want to do here */
-#if defined(_MSC_VER)
-#pragma warning( push )
-#pragma warning( disable : 4146 )
-#endif
-    mask = - ( ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 ) );
-#if defined(_MSC_VER)
-#pragma warning( pop )
-#endif
+    mask = mbedtls_cf_uint_mask( diff );
 
     /*
      * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding