$1($a$).[10$ points$]$

Write a behavioral Verilog module for a $2-$input, $4-$bit multiplexer with the function table shown below.

Name the data input and output vectors D$0,$ D$1,$ and Y$,$ and index them from $1$ to $4.$

Inputs Outputs

EN$\_$L S $1$Y $2$Y $3$Y $4$Y

$1$ x $0000$

$001$D$02$D$03$D$04$D$0$

$011$D$12$D$13$D$14$D$1$

$1($b$).[10$ points$]$

Write the Verilog test bench that tests for correct functioning of the module in the question $(1)$a$.$ For

each value of the function inputs, it should check the output is correct for all combinations of data$-$input

values and display an informative error message if it is incorrect. Insert one or more errors into to the

module for question $1($a$)$ and verify that your error messages are working