Beh decoder 2 to 4 for struct 3 to 8

--18.01.2019 Igor Kojic

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity dec2to4 is
  Port (
    y: in std_logic_vector(1 downto 0);
    x: out std_logic_vector(3 downto 0);
    ei: in std_logic
  );
end dec2to4;

architecture Behavioral of dec2to4 is

begin
decoder: process (y,ei) is
    begin
    if(ei = '1')then
        if (y(1) = '0' and y(0) = '0') then
            x(0) <= '1';
        else
            x(0) <= '0';
        end if;
        if (y(1) = '0' and y(0) = '1') then
            x(1) <= '1';
        else
            x(1) <= '0';
        end if;
        if (y(1) = '1' and y(0) = '0') then
            x(2) <= '1';
        else
            x(2) <= '0';
        end if;
        if (y(1) = '1' and y(0) = '1') then
            x(3) <= '1';
        else
            x(3) <= '0';
        end if;
    else
        x<= "0000";
    end if;
end process;
end Behavioral;