-- Sumador: se utiliza el componente fa (full-adder)

- Declaración de la entidad
Entity sumador is
port (

A, B: in bit_vector(3 downto 0);
Cin: in bit;
S: out bit_vector(3 downto 0);
Cout: out bit);

end sumador ;

-- Definición de la arquitectura
Architecture struct of sumador is

component fa

port (

a, b, c_i:in bit;
s, c_o: out bit);

end component;

signal c0, c1, c2: bit;

begin

u1: fa port map (A(0), B(0), Cin, S(0), c0);
u2: fa port map (A(1), B(1), c0, S(1), c1);
u3: fa port map (A(2), B(2), c1, S(2), c2);
u4: fa port map (A(3), B(3), c2, S(3), Cout);

end struct;