mux4.vhd

在quartus开发环境下

library ieee;
use ieee.std_logic_1164.all;
entity mux4 is
port(d0,d1,d2,d3:in std_logic;
     g:in std_logic;
     a:in std_logic_vector(1 downto 0);
     y:out std_logic);
end;
architecture one of mux4 is
begin
process(a,g,d0,d1,d2,d3) 
begin
	if g='0' then y<='0';
	else
	case a is
		when "00"=>y<=d0;
		when "01"=>y<=d1;
		when "10"=>y<=d2;
		when "11"=>y<=d3;
	    when others=>y<='0';
	end case;
	end if;
end process;
end;