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------------------------------------------------------------------------------
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-- This file is a part of the LPP VHDL IP LIBRARY
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-- Copyright (C) 2009 - 2010, Laboratory of Plasmas Physic - CNRS
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--
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-- This program is free software; you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation; either version 3 of the License, or
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-- (at your option) any later version.
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--
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program; if not, write to the Free Software
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-- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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-------------------------------------------------------------------------------
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library IEEE;
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use IEEE.numeric_std.all;
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use IEEE.std_logic_1164.all;
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library lpp;
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use lpp.general_purpose.all;
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entity RShifter is
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generic(
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Input_SZ : integer := 16;
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shift_SZ : integer := 4
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);
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port(
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clk : in std_logic;
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reset : in std_logic;
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shift : in std_logic;
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OP : in std_logic_vector(Input_SZ-1 downto 0);
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cnt : in std_logic_vector(shift_SZ-1 downto 0);
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RES : out std_logic_vector(Input_SZ-1 downto 0)
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);
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end entity;
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architecture ar_RShifter of RShifter is
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signal REG : std_logic_vector(Input_SZ-1 downto 0);
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signal RESSHIFT: std_logic_vector(Input_SZ-1 downto 0);
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begin
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RES <= REG;
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RESSHIFT <= std_logic_vector(SHIFT_RIGHT(signed(OP),to_integer(unsigned(cnt))));
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process(clk,reset)
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begin
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if reset = '0' then
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REG <= (others => '0');
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elsif clk'event and clk ='1' then
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if shift = '1' then
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REG <= RESSHIFT;
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end if;
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end if;
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end process;
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end ar_RShifter;
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