Driver starting.
    a=00000000,    b=FFFFFFFF,  cin=0
  sum=FFFFFFFF, cout=0,   s2=FFFFFFFF,  co2=0, cntr=0000,  at=38 ns

    a=10000111,    b=FFFFFFFF,  cin=1
  sum=10000111, cout=1,   s2=10000111,  co2=1, cntr=0001,  at=78 ns

    a=20000222,    b=FFFFFFFF,  cin=0
  sum=20000221, cout=1,   s2=20000221,  co2=1, cntr=0010,  at=118 ns

    a=30000333,    b=FFFFFFFF,  cin=1
  sum=30000333, cout=1,   s2=30000333,  co2=1, cntr=0011,  at=158 ns