--  Copyright (C) 2004-2005 Digish Pandya <digish.pandya@gmail.com>--  This program is free software; you can redistribute it and/or modify--  it under the terms of the GNU General Public License as published by--  the Free Software Foundation; either version 2 of the License, or--  (at your option) any later version.----  This program is distributed in the hope that it will be useful,--  but WITHOUT ANY WARRANTY; without even the implied warranty of--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the--  GNU General Public License for more details.----  You should have received a copy of the GNU General Public License--  along with this program; if not, write to the Free Software--  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.-- producing delay of 20 unitlibrary IEEE;use IEEE.STD_LOGIC_1164.ALL;use IEEE.STD_LOGIC_ARITH.ALL;use IEEE.STD_LOGIC_UNSIGNED.ALL;entity shift_20d is    Port ( xin : in std_logic_vector(7 downto 0);           xout : out std_logic_vector(7 downto 0);           clock : in std_logic);end shift_20d;architecture Behavioral of shift_20d issignal shift_reg: std_logic_vector (159 downto 0);--signal shift_reg: std_logic_vector (119 downto 0);begin   shift:   process(clock)   begin	if(clock'event and clock = '1') then	   			shift_reg <= xin & shift_reg(159 downto 8);	end if;  end process;	  xout <= shift_reg(7 downto 0);end Behavioral;