md5_round4
md5_round4(&A, B, C, D, X0, 0xf4292244L, 6);
md5_round4(&D, A, B, C, X7, 0x432aff97L, 10);
md5_round4(&C, D, A, B, X14, 0xab9423a7L, 15);
md5_round4(&B, C, D, A, X5, 0xfc93a039L, 21);
md5_round4(&A, B, C, D, X12, 0x655b59c3L, 6);
md5_round4(&D, A, B, C, X3, 0x8f0ccc92L, 10);
md5_round4(&C, D, A, B, X10, 0xffeff47dL, 15);
md5_round4(&B, C, D, A, X1, 0x85845dd1L, 21);
md5_round4(&A, B, C, D, X8, 0x6fa87e4fL, 6);
md5_round4(&D, A, B, C, X15, 0xfe2ce6e0L, 10);
md5_round4(&C, D, A, B, X6, 0xa3014314L, 15);
md5_round4(&B, C, D, A, X13, 0x4e0811a1L, 21);
md5_round4(&A, B, C, D, X4, 0xf7537e82L, 6);
md5_round4(&D, A, B, C, X11, 0xbd3af235L, 10);
md5_round4(&C, D, A, B, X2, 0x2ad7d2bbL, 15);
md5_round4(&B, C, D, A, X9, 0xeb86d391L, 21);