library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;

entity adders_4 is
    port(A,B : in std_logic_vector(7 downto 0);
         CI : in std_logic;
         SUM : out std_logic_vector(7 downto 0);
         CO : out std_logic);
end adders_4;

architecture archi of adders_4 is
    signal tmp: std_logic_vector(8 downto 0);
begin

    tmp <= conv_std_logic_vector((conv_integer(A) + conv_integer(B) + conv_integer(CI)),9);
    SUM <= tmp(7 downto 0);
    CO <= tmp(8);

end archi;