+# if __GNUC__>=4 && __GNUC_MINOR__>=4 /* "h" constraint is no more since 4.4 */
+# define BN_UMULT_HIGH(a,b) (((__uint128_t)(a)*(b))>>64)
+# define BN_UMULT_LOHI(low,high,a,b) ({ \
+ __uint128_t ret=(__uint128_t)(a)*(b); \
+ (high)=ret>>64; (low)=ret; })
+# else
+# define BN_UMULT_HIGH(a,b) ({ \