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--   File Name    : mux2to1.vbe                               --

--   Description  : The 32-bit 2-to-1 mux                     --

--   Purpose      : To be used by ASIMUT and SCMAP            --

--   Date         : Aug 30, 2001                              --

--   Version      : 1.1                                       --

--   Author       : Martadinata A.                            --

--   Address      : VLSI RG, Dept. of Electrical Engineering  --

--                  ITB, Bandung, Indonesia                   --

--   E-mail       : marta@vlsi.itb.ac.id                      --

entity mux2to1 is

port(

  y             : in       bit_vector(63 downto 0);

  sel           : in       bit;

  clk           : in       bit;

  rst           : in       bit;

  cp            : out      bit_vector(31 downto 0);

  vdd           : in       bit;

  vss           : in       bit

  );

end mux2to1;

architecture vbe of mux2to1 is

signal reg   : reg_vector(31 downto 0) register;

signal cpp   : bit_vector(31 downto 0);

begin

  assert ((vdd and not (vss)) = '1')

    report "power supply is missing on mux2to1"

    severity warning;

  with sel select

     cpp <= y(63 downto 32) when '0',

            y(31 downto 0) when '1';

  REG1 : BLOCK ((clk = '1') and not clk'STABLE)

     BEGIN

     reg <= GUARDED X"1111_1111" when(rst='1') else not cpp;

  END BLOCK REG1;

  cp <= not reg;

end;