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--******************************************************************************
--*                                                                            *
--*                              4 x 4 selector                                *
--*                                                     Device : XC9536-PC44   *
--*                                                     Author : Seiichi Inoue *
--******************************************************************************

library ieee;                                    -- Defines std_logic types
use ieee.std_logic_1164.all;

entity Selector1 is
  port ( A, B, C, D : in std_logic_vector(3 downto 0); -- Defines ports
         Q : out std_logic_vector(3 downto 0);
         SEL : in std_logic_vector(1 downto 0));      
end;

architecture Selector1_arch of Selector1 is
begin
  process( SEL ) begin
    if SEL = "00" then
      Q <= A;                                    -- SEL=00  A -> OUT
    elsif SEL = "01" then
      Q <= B;                                    -- SEL=01  B -> OUT
    elsif SEL = "10" then
      Q <= C;                                    -- SEL=10  C -> OUT
    else
      Q <= D;                                    -- SEL=11  D -> OUT
    end if;
  end process;
end Selector1_arch;

--******************************************************************************
--*                           end of 4 x 4 selector                            *
--******************************************************************************