type t = {
  cla : int;
  ins : int;
  p1 : int;
  p2 : int;
}

let parse command = {
  cla = Bytes.get command 0 |> Char.code;
  ins = Bytes.get command 1 |> Char.code;
  p1 = Bytes.get command 2 |> Char.code;
  p2 = Bytes.get command 3 |> Char.code;
}