entity alu is
port(
CLK : in STD_LOGIC;
A : in STD_LOGIC_VECTOR(3 downto 0);
B : in STD_LOGIC_VECTOR(3 downto 0);
C : out STD_LOGIC_VECTOR(3 downto 0));
end alu;
architecture behavioral of alu is
-- dummy signal
signal C_INT : STD_LOGIC_VECTOR(3 downto 0);
begin
C <= C_INT;
process begin
if rising_edge(CLK) then
C_INT <= A and B and C_INT;
end if;
end process;
end behavioral;