% Logik og sprog, Modul 2, datalogi RUC      Henning Christiansen
%
% 
% Logiske kredse implementeret i Prolog;
% kapitel 5 i "Sprog og abstrakte maskiner"
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% (c) 2000, Henning Christiansen



% not
not(0, 1).
not(1, 0).

% AND
and(0, 0, 0).
and(0, 1, 0).
and(1, 0, 0).
and(1, 1, 1).

% XOR
xor(0, 0, 0).
xor(0, 1, 1).
xor(1, 0, 1).
xor(1, 1, 0).

% OR
or(0, 0, 0).
or(0, 1, 1).
or(1, 0, 1).
or(1, 1, 1).

halfadder(A, B, Carry, Sum):-
        and(A, B, Carry),
        xor(A, B, Sum).

fulladder(A, B, Carryin,
                 Sum, Carryout):-
        xor(A, B, X),
        and(A, B, Y),
        and(X, Carryin, Z),
        xor(Carryin, X, Sum),
        or(Y, Z, Carryout).

nand1(0, 0, 1).
nand1(0, 1, 1).
nand1(1, 0, 1).
nand1(1, 1, 0).

nand2(A, B, X):-
        and(A, B, M),
        not(M, X).
	
aand1(A, B, C, X):-
        and(A, B, M),
        and(M, C, X).

aand2(A, B, C, X):-
        and(M, C, X),
        and(A, B, M).