
Create a 1-bit wide, 256-to-1 multiplexer. The 256 inputs are all packed
into a single 256-bit input vector. sel=0 should select in[0], sel=1
selects bits in[1], sel=2 selects bits in[2], etc.

module TopModule (
  input [255:0] in,
  input [7:0] sel,
  output  out
);

