Alternate Carry Process
Carry: PROCESS( A, B, Cin)
IF ( A = ‘1’ AND B = ‘1’ ) THEN
ELSIF ( A = ‘1’ AND Cin = ‘1’ ) THEN
ELSIF ( B = ‘1’ AND Cin = ‘1’ ) THEN
Notes:
Alternatively, the Carry output could have been described using programming language constructs instead of the logic equations shown previously. Here, a set of nested if-then-else statements is used to implement the table lookup method. A case statement could also be used.