Prolog Extra Credit Homework
Basic Boolean Operators in Prolog
or(0,0,0).
or(0,1,1).
or(1,0,1).
or(1,1,1).
and(0,0,0)
and(0,1,0).
and(1,0,0).
and(1,1,1).
not(0,1).
not(1,0).
xor(0,0,0).
xor(0,1,1).
xor(1,0,1).
xor(1,1,0).
Half-adder:
halfadder(A,B,Carry,Sum):xor(A,B,Sum),and(A,B,Carry).
looks a lot like?
xor()
and()
Full-adder:
or-gate
Exercise: Write the prolog
rule for a full adder.
fulladder(A,B,CarryIn,Sum,CarryOut):halfadder(A,B,S,C1),
halfadder(S,CarryIn,Sum,C2),
or(C1,C2,CarryOut).
Programming Problem 1:

Write a prolog program that will combine one half-adder and
three full-adders to perform 4-bit arithmetic.
add4bits([A3,A2,A1,A0],[B3,B2,B1,B0],[Sum3,Sum2,Sum1,Sum0],CarryOut):-
these are lists
Programming Problem 2:
A 4-input multiplexer accepts
4 input bits and outputs
exactly one of them.
The bit to be outputted
depends on the values of the
control lines - C0 and C1.
For example, if C0 = 0 and
C1 = 1 then Output = D2.
4-bit Multiplexer Logic:
or-gate
and-gate
complementor
multiplex4bits([D3,D2,D1,D0],[C1,C0],Output):- ...