
This combinational circuit is supposed to recognize 8-bit keyboard
scancodes for keys 0 through 9. It should indicate whether one of the 10
cases were recognized (valid), and if so, which key was detected. If the
8-bit input is 8'h45, 8'h16, 8'h1e, 8'h26, 8'h25, 8'h2e, 8'h36, 8'h3d,
8'h3e, or 8'h46, the 4-bit output will be set to 0, 1, 2, 3, 4, 5, 6, 7,
8, or 9 respectively, the 1-bit valid would be set to 1. If the input
does not match any of the cases, both output signals would be set to 0.

module TopModule (
  input [7:0] code,
  output reg [3:0] out,
  output reg valid
);

