MD5_SHIFT_14
FF(b, c, d, a, x_3, MD5_SHIFT_14, MD5_CONST_o(3)); /* 4 */
FF(b, c, d, a, x_7, MD5_SHIFT_14, MD5_CONST_o(7)); /* 8 */
FF(b, c, d, a, x_11, MD5_SHIFT_14, MD5_CONST_o(11)); /* 12 */
FF(b, c, d, a, x_15, MD5_SHIFT_14, MD5_CONST_o(15)); /* 16 */