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:

looks a lot like?

xor() and()

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

Full-adder:

or-gate

Exercise: Write the prologrule 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 accepts4 input bits and outputsexactly one of them.

The bit to be outputteddepends 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:

and-gate

or-gate

complementor

multiplex4bits([D3,D2,D1,D0],[C1,C0],Output):- ...