Multiplexer

Multiplexer (MUX)

A multiplexer (MUX) selects one of several input signals and routes it to the output, based on select lines.

A 4-to-1 MUX has:

• 4 data inputs: D0, D1, D2, D3
• 2 select lines: S1, S0
• 1 output Y

The select lines form a 2-bit binary address: S1 is the MSB, S0 is the LSB. Together they select which input to pass through.

Multiplexers are used everywhere: bus arbitration, data routing, function generators, and implementing any Boolean function using a single MUX.

Your Task

Implement mux4to1(d0, d1, d2, d3, s1, s0) that returns the selected input based on the select lines.