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       = DECODE_MISS    --

--  version      = 1.0            --

--  last update  = 25/06/01       --

--  author       = Jose Nunez     --

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

-- FUNCTION

-- decodes the input (Huffman) miss type code to give a mask,

-- miss length and miss+literal character length

-- PIN LIST

-- CODE         = input miss type code (Huffman)

-- M_LIT_LENGTH = length of miss type code and any required literal characters

-- SELECT_MOVE  = select a move vector

-- MASK         = decoded mask

library ieee,dzx;

use ieee.std_logic_1164.all;

entity DECODE_MISS is

port

(

        CODE : in bit_vector(3 downto 0);

        M_LIT_LENGTH : out bit_vector(5 downto 0);

        SELECT_MOVE : out bit_vector(2 downto 0);

        MASK : out bit_vector(4 downto 0)

);

end DECODE_MISS;

architecture HUFFMAN of DECODE_MISS is

begin

TREE_DEC : process(CODE)

begin

case CODE is

    when "1000" | "1001" | "1010" |"1011" | "1100"  | "1101"  | "1110" | "1111"

                                => MASK <= "10000";

                M_LIT_LENGTH <= "000010";

                        SELECT_MOVE <= "000";

    when "0100" | "0101"| "0110" | "0111"

                        =>  MASK <= "11111";

                    M_LIT_LENGTH <= "100011";

                        SELECT_MOVE <= "001";

    when "0010" | "0011"

                =>  MASK <= "11000";

                    M_LIT_LENGTH <= "001100";

                        SELECT_MOVE <= "010";

    when "0001"

                                =>  MASK <= "11100";

                    M_LIT_LENGTH <= "010101";

                        SELECT_MOVE <= "011";

    when "0000"

                =>  MASK <= "11110";

                    M_LIT_LENGTH <= "011101";

                        SELECT_MOVE <= "100";

    when others

                =>  MASK <= "00000";

                    M_LIT_LENGTH <= "000000";

                        SELECT_MOVE <= "101";

end case;

end process TREE_DEC;

end HUFFMAN; -- end of architecture