74x139 Using when – else statement in data flow model

74x139     Using when – else statement in data flow model

library IEEE;

use IEEE.std_logic_1164.all;

entity dec74x139 is

port (     G_L: in STD_LOGIC;

                                A, B: in STD_LOGIC;

                                Y0_L, Y1_L, Y2_L, Y3_L: out STD_LOGIC);

end dec74x139;

architecture arch2 of dec74x139 is

begin

                Y0_L <= ‘0’ when G_L & A & B = “000” else

                                ‘1’;

                Y1_L <= ‘0’ when G_L & A & B = “001” else

                                ‘1’;

                Y2_L <= ‘0’ when G_L & A & B = “010” else

                                ‘1’;

                Y3_L <= ‘0’ when G_L & A & B = “011” else

                                ‘1’;

end arch2;