+# 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; \
+ asm ("mulq %3" \
+ : "=a"(discard),"=d"(ret) \
+ : "a"(a), "g"(b) \
+ : "cc"); \
+ ret; })
+# define BN_UMULT_LOHI(low,high,a,b) \
+ asm ("mulq %3" \
+ : "=a"(low),"=d"(high) \
+ : "a"(a),"g"(b) \
+ : "cc");
+# endif
+# elif (defined(_M_AMD64) || defined(_M_X64)) && defined(SIXTY_FOUR_BIT)
+# if defined(_MSC_VER) && _MSC_VER>=1400
+ unsigned __int64 __umulh (unsigned __int64 a,unsigned __int64 b);
+ unsigned __int64 _umul128 (unsigned __int64 a,unsigned __int64 b,
+ unsigned __int64 *h);
+# pragma intrinsic(__umulh,_umul128)
+# define BN_UMULT_HIGH(a,b) __umulh((a),(b))
+# define BN_UMULT_LOHI(low,high,a,b) ((low)=_umul128((a),(b),&(high)))
+# endif