MAC za FIR filtar, Direktna forma parametrizovano

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use ieee.std_logic_unsigned.all;
use IEEE.NUMERIC_STD.ALL;

entity mac is
    generic (input_data_width : natural :=12);
    Port ( clk_i : in STD_LOGIC;
           ce_i : in STD_LOGIC;
           u_i : in STD_LOGIC_VECTOR (input_data_width-1 downto 0);
           b_i : in STD_LOGIC_VECTOR (input_data_width-1 downto 0);
           u_o : out STD_LOGIC_VECTOR (input_data_width-1 downto 0);
           mac_i : in STD_LOGIC_VECTOR (2*input_data_width-1 downto 0);
           mac_o : out STD_LOGIC_VECTOR (2*input_data_width-1 downto 0));
end mac;

architecture Behavioral of mac is
    signal reg_s : STD_LOGIC_VECTOR (input_data_width-1 downto 0):=(others=>'0');
begin
    process(clk_i)
    begin
        if (clk_i'event and clk_i = '1')then
            if (ce_i = '1') then
                reg_s <= u_i;
            end if;
        end if;
    end process;
    mac_o <= std_logic_vector(signed(mac_i) + (signed(u_i) * signed(b_i)));
    u_o <= reg_s;
end Behavioral;