Subversion Repositories xmatchpro

--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       = MT_CODER    --

--  version      = 1.0         --

--  last update  = 16/06/98    --

--  author       = Jose Nunez  --

---------------------------------

-- FUNCTION

-- match type coder. Converts incoming match type to a Huffman code word

-- and associated length.

-- PIN LIST

-- MATCH_TYPE = input match type bus

-- CODE       = output Huffman code (left aligned)

-- LENGTH     = length (number of valid bits) in the output code

library ieee,dzx;

use ieee.std_logic_1164.all;

entity MT_CODER is

port

(

    MATCH_TYPE : in bit_vector(3 downto 0);

        CODE : out bit_vector(5 downto 0);

        LENGTH : out bit_vector(2 downto 0)

);

end MT_CODER;

architecture HUFFMAN of MT_CODER is

begin

MATCH : process(MATCH_TYPE)

begin

case MATCH_TYPE is

    when "0000" => CODE <= "100000"; LENGTH <= "001";

    when "0001" => CODE <= "010000"; LENGTH <= "011";

    when "0010" => CODE <= "001111"; LENGTH <= "110";

    when "0011" => CODE <= "001000"; LENGTH <= "100";

    when "0100" => CODE <= "001110"; LENGTH <= "110";

    when "1000" => CODE <= "000000"; LENGTH <= "011";

    when "1001" => CODE <= "001101"; LENGTH <= "110";

    when "1100" => CODE <= "001100"; LENGTH <= "110";

    when others => CODE <= "000000"; LENGTH <= "000";

end case;

end process MATCH;

end HUFFMAN; -- end of architecture