The 74AUP2G157 is a single 2-input multiplexer which select data from two data inputs (I0 and I1) under control of a common data select input (S). The state of the common data select input determines the particular register from which the data comes. The output (Y,Y) presents the selected data in the true (non-inverted) and complement form. The enable input (E) is active LOW. WhenEis HIGH, the output Y is forced LOW and the outputYis forced HIGH regardless of all other input conditions.