74x138 Behavioral model using if – else statement

74x138     Behavioral model using if – else statement

library IEEE;

use IEEE.std_logic_1164.all;

entity dec74x138 is

port ( G1, G2A_L, G2B_L : in  STD_LOGIC;

                    A, B, C : in   STD_LOGIC;

                    Y0_L, Y1_L, Y2_L, Y3_L, Y4_L, Y5_L, Y6_L, Y7_L:  out  STD_LOGIC);

end dec74x138;

architecture arch6 of dec74x138 is

begin

     process (G1, G2A_L, G2B_L, A, B, C)

     begin     

Y0_L <=  ‘1’; Y1_L <= ‘1’; Y2_L <= ‘1’; Y3_L <=  ‘1’;

Y4_L <=  ‘1’; Y5_L <= ‘1’; Y6_L <= ‘1’; Y7_L <=  ‘1’;

if G1 & G2A_l & G2B_L = “100” then

  if A & B & C = “000” then          Y0_L <= ‘0’;

     elsif A & B & C = “001” then    Y1_L <= ‘0’;

     elsif A & B & C = “010” then    Y2_L <= ‘0’;

     elsif G_L & A & B = “011” then    Y3_L <= ‘0’;

     elsif G_L & A & B = “100” then    Y4_L <= ‘0’;

     elsif G_L & A & B = “101” then    Y5_L <= ‘0’;

     elsif G_L & A & B = “110” then    Y6_L <= ‘0’;

     elsif G_L & A & B = “111” then    Y7_L <= ‘0’;

  end if;

end if;

     end process;

end arch6;