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[/] [xmatchpro/] [trunk/] [xmw4-comdec/] [src/] [shift_literal.vhd] - Rev 8
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--This library is free software; you can redistribute it and/or --modify it under the terms of the GNU Lesser General Public --License as published by the Free Software Foundation; either --version 2.1 of the License, or (at your option) any later version. --This library 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 --Lesser General Public License for more details. --You should have received a copy of the GNU Lesser General Public --License along with this library; if not, write to the Free Software --Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA -- e_mail : j.l.nunez-yanez@byacom.co.uk ------------------------------------ -- ENTITY = SHIFT_LITERAL -- -- version = 2.0 -- -- last update = 04/08/99 -- -- author = Jose Nunez -- ------------------------------------ -- FUNCTION -- barrel shifter to remove the match location and match type -- codes from the decoded data, leaving just literal characters. -- PIN LIST -- DIN_LIT = input data -- CM_LENGTH = length of the match location and match type codes -- DOUT_LIT = output shifted data library ieee,dzx; use ieee.std_logic_1164.all; use dzx.attributes.all; entity SHIFT_LITERAL is port ( DIN_LIT : in bit_vector(34 downto 0) ; CM_LENGTH : in bit_vector(3 downto 0) ; -- DECOMP : in bit ; DOUT_LIT : out bit_vector(31 downto 0) ); end SHIFT_LITERAL; architecture BARREL of SHIFT_LITERAL is begin BSHIFT : process(DIN_LIT , CM_LENGTH ) begin -- if (DECOMP = '0') then case CM_LENGTH is when "0000" => DOUT_LIT <= DIN_LIT(34 downto 3); when "0001" => DOUT_LIT <= DIN_LIT(33 downto 2); when "0010" => DOUT_LIT <= DIN_LIT(32 downto 1); when "0011" => DOUT_LIT <= DIN_LIT(31 downto 0); when "0100" => DOUT_LIT <= DIN_LIT(30 downto 0) & '0'; when "0101" => DOUT_LIT <= DIN_LIT(29 downto 0) & "00"; when "0110" => DOUT_LIT <= DIN_LIT(28 downto 0) & "000"; when "0111" => DOUT_LIT <= DIN_LIT(27 downto 0) & "0000"; when "1000" => DOUT_LIT <= DIN_LIT(26 downto 0) & "00000"; when "1001" => DOUT_LIT <= DIN_LIT(25 downto 0) & "000000"; when "1010" => DOUT_LIT <= DIN_LIT(24 downto 0) & "0000000"; when "1011" => DOUT_LIT <= DIN_LIT(23 downto 0) & "00000000"; when "1100" => DOUT_LIT <= DIN_LIT(22 downto 0) & "000000000"; when "1101" => DOUT_LIT <= DIN_LIT(21 downto 0) & "0000000000"; when others => DOUT_LIT <= x"00000000"; end case; -- else -- DOUT_LIT <= x"00000000"; -- end if; end process BSHIFT; end BARREL; -- end of architecture