: "r"(a), "r"(b)); \
ret; })
# endif /* compiler */
-# elif defined(__x86_64) && defined(SIXTY_FOUR_BIT_LONG)
+# elif (defined(__x86_64) || defined(__x86_64__)) && \
+ (defined(SIXTY_FOUR_BIT_LONG) || defined(SIXTY_FOUR_BIT))
# if defined(__GNUC__)
# define BN_UMULT_HIGH(a,b) ({ \
register BN_ULONG ret,discard; \