
Parity checking is often used as a simple method of detecting errors when
transmitting data through an imperfect channel. Create a circuit that
will compute a parity bit for a 8-bit byte (which will add a 9th bit to
the byte). We will use "even" parity, where the parity bit is just the
XOR of all 8 data bits.

module TopModule (
  input [7:0] in,
  output parity
);

