code CrLf=9, IntOut=11;

func Not(A);
int A;
return not A;

func And(A, B);
int A, B;
return A and B;

func Or(A, B);
int A, B;
return A or B;

func Xor(A, B);
int A, B;
return Or(And(A, Not(B)), And(Not(A), B));

proc HalfAdd(A, B, S, C);
int A, B, S, C;
[S(0):= Xor(A, B);
 C(0):= And(A, B);
];

proc FullAdd(A, B, Ci, S, Co);
int A, B, Ci, S, Co;            \(Ci and Co are reversed from drawing)
int S0, S1, C0, C1;
[HalfAdd(Ci, A, @S0, @C0);
 HalfAdd(S0, B, @S1, @C1);
 S(0):= S1;
 Co(0):= Or(C0, C1);
];

proc Add4Bits(A0, A1, A2, A3, B0, B1, B2, B3, S0, S1, S2, S3, Co);
int A0, A1, A2, A3, B0, B1, B2, B3, S0, S1, S2, S3, Co;
int Co0, Co1, Co2;
[FullAdd(A0, B0, 0,   S0, @Co0);
 FullAdd(A1, B1, Co0, S1, @Co1);
 FullAdd(A2, B2, Co1, S2, @Co2);
 FullAdd(A3, B3, Co2, S3, Co);
];

proc BinOut(D, A0, A1, A2, A3, C);
int D, A0, A1, A2, A3, C;
[IntOut(D, C&1);
IntOut(D, A3&1);
IntOut(D, A2&1);
IntOut(D, A1&1);
IntOut(D, A0&1);
];

int S0, S1, S2, S3, C;
[Add4Bits(1, 0, 0, 0, 0, 0, 1, 0, @S0, @S1, @S2, @S3, @C);  \0001 + 0100 = 00101
 BinOut(0, S0, S1, S2, S3, C);  CrLf(0);
 Add4Bits(1, 0, 1, 0, 0, 1, 1, 1, @S0, @S1, @S2, @S3, @C);  \0101 + 1110 = 10011
 BinOut(0, S0, S1, S2, S3, C);  CrLf(0);
 Add4Bits(1, 1, 1, 1, 1, 1, 1, 1, @S0, @S1, @S2, @S3, @C);  \1111 + 1111 = 11110
 BinOut(0, S0, S1, S2, S3, C);  CrLf(0);
]