2-to-1 Multiplexer

The entity mux2_1 has two data inputs (i_d0, i_d1) of type std_logic, a selector (i_sel) of type std_logic and one output (o_q) of type std_logic.

When i_sel is '0', output o_q takes the value of i_d0. When i_sel is '1', the output takes the value of i_d1.