Subversion Repositories mips_fault_tolerant

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-- Company: 

-- Engineer: 

-- 

-- Create Date:    19:46:29 06/24/2012 

-- Design Name: 

-- Module Name:    NPC_mux - Behavioral 

-- Project Name: 

-- Target Devices: 

-- Tool versions: 

-- Description: 

--

-- Dependencies: 

--

-- Revision: 

-- Revision 0.01 - File Created

-- Additional Comments: 

--

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library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

-- Uncomment the following library declaration if using

-- arithmetic functions with Signed or Unsigned values

--use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if instantiating

-- any Xilinx primitives in this code.

--library UNISIM;

--use UNISIM.VComponents.all;

entity NPC_mux is

port (

      clk   : in std_logic;

                Zero_in,EqNq : in std_logic;

                From_N: in std_logic_vector(31 downto 0);

                From_A: in std_logic_vector(31 downto 0);

                From_M: in std_logic_vector(31 downto 0);

                PCSource: in std_logic_vector(1 downto 0);

                NPC_out: out std_logic_vector(31 downto 0)

                );

end NPC_mux;

architecture Behavioral of NPC_mux is

begin

      process(clk,PCSource,From_N,From_A,From_M,Zero_in)

                begin

                if (FALLING_EDGE(clk))then

           case PCSource is

                    when "00" => NPC_out <= From_N;

                    when "01" =>

                             case EqNq is

                                  when '0' =>

                                  if Zero_in = '1' then

                                  NPC_out <= From_M;

                                  else

                                  NPC_out <= From_N;

                                  end if;

                                  when '1' =>

                                  if Zero_in = '0' then

                                  NPC_out <= From_M;

                                  else

                                  NPC_out <= From_N;

                                  end if;

                                  when others => NPC_out <= (others => '0');

                                  end case;

                         when "10" => NPC_out <= From_A;

                         when others => NPC_out <= (others => '0');

                end case;

      end if;

      end process;

end Behavioral;