---------------------------------------------------------------------- -- node Adder ---------------------------------------------------------------------- node Adder (A,B,Cin : bool) returns (S,Cout : bool); let S = A xor B xor Cin; Cout = (A and B) or (B and Cin) or (A and Cin); tel ---------------------------------------------------------------------- -- node FourbitAdder -- multiple instances of the same node -- local variables -- tuple returns ---------------------------------------------------------------------- node FourbitAdder (A3,A2,A1,A0,B3,B2,B1,B0,Cin:bool) returns (Cout,S3,S2,S1,S0:bool); var C2,C1,C0:bool; let (S0,C0) = Adder(A0,B0,Cin); (S1,C1) = Adder(A1,B1,C0); (S2,C2) = Adder(A2,B2,C1); (S3,Cout) = Adder(A3,B3,C2); tel