This information is part of the Modelica Standard Library maintained by the Modelica Association.

It is an adding circuit for binary numbers with input carry bit, which consists of two HalfAdders.

a.y, b.y and c.y are the inputs of the FullAdder.
cout = Or1.y and h.s are the outputs of the FullAdder.

t is the pick-up instant of the next bit(s) in the simulation.

a.y      b.y     c.y      cout       h.s        t

1        0        0        0          1        1
0        1        0        0          1        2
0        0        1        0          1        3
1        1        0        1          0        4
0        1        1        1          0        5
1        0        1        1          0        6
1        1        1        1          1        7
0        0        0        0          0        8

The simulation stop time should be 10 seconds.