----------------------------- info header [part 1 of the VHDL file] -- Author -- Date -- Project name -- Module name -- -- Detailed module description -- -- -- -- -- -- -- -- Revision: -- A - initial design -- B - -- ----------------------------- -- define libraries to be used [part 2 of the VHDL file] library ieee; --always use this library use ieee.std_logic_1164.all; --always use this library use ieee.numeric_std.all; --use this library if arithmetic required --Entity declaration [part 3 of the VHDL file]. entity alu is generic ( data_width : integer := 32 ); port ( clk : in std_logic; A : in std_Logic_vector(data_width - 1 downto 0); B : in std_logic_vector(data_width - 1 downto 0); op : in std_logic_vector(3 downto 0); R : out std_logic_vector(data_width - 1 downto 0); flag : out std_logic ); end alu; --define inside of the module architecture behavioral of alu is --define inside use signals and components [part 4 of the VHDL file] begin --define the operation of the module! [part 5 of the VHDL file] flag <= '0'; --optional end behavioral;