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_MT      --

--  version      = 1.0            --

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

--  author       = Jose Nunez     --

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

-- FUNCTION

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

-- match length and match+literal character length

-- PIN LIST

-- CODE         = input match type code (Huffman)

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

-- M_TYPE       = decoded match type

library ieee,dzx;

use ieee.std_logic_1164.all;

entity DECODE_MT is

port

(

        CODE : in bit_vector(5 downto 0);

        M_LIT_LENGTH : out bit_vector(4 downto 0);

        SELECT_MOVE : out bit_vector(2 downto 0);

        RL_DETECTED : out bit;

        M_TYPE : out bit_vector(3 downto 0)

);

end DECODE_MT;

architecture HUFFMAN of DECODE_MT is

begin

TREE_DEC : process(CODE)

begin

case CODE is

    when "100000" | "100010" | "100100" |"100110" | "101000"  | "101010"  | "101100" | "101110" |

                "110000" | "110010" | "110100" |"110110" | "111000"  | "111010"  | "111100" | "111110" |

                "100001" | "100011" | "100101" |"100111" | "101001"  | "101011"  | "101101" | "101111" |

                "110001" | "110011" | "110101" |"110111" | "111001"  | "111011"  | "111101" | "111111"

                =>  M_TYPE <= "0000";

                    M_LIT_LENGTH <= "00010";

                                SELECT_MOVE <= "001";

                                RL_DETECTED <= '0';

    when "000000" | "000001"| "000010" | "000011" | "000100" | "000101" | "000110" | "000111"

                        =>  M_TYPE <= "1000";

                    M_LIT_LENGTH <= "01100";

                        SELECT_MOVE <= "010";

                        RL_DETECTED <= '0';

    when "010000" | "010001"| "010010" | "010011" | "010100" | "010101" | "010110" | "010111"

                =>  M_TYPE <= "0001";

                    M_LIT_LENGTH <= "01100";

                        SELECT_MOVE <= "010";

                        RL_DETECTED <= '0';

    when "011000" | "011001"| "011010" | "011011" | "011100" | "011101" | "011110" | "011111"

                                =>  M_TYPE <= "0000";

                    M_LIT_LENGTH <= "00100";

                        SELECT_MOVE <= "111";

                        RL_DETECTED <= '1';

    when "001000" |"001001" | "001010" | "001011"

                =>  M_TYPE <= "0011";

                    M_LIT_LENGTH <= "10101";

                        SELECT_MOVE <= "011";

                        RL_DETECTED <= '0';

    when "001111"

                =>  M_TYPE <= "0010";

                    M_LIT_LENGTH <= "01111";

                        SELECT_MOVE <= "100";

                        RL_DETECTED <= '0';

    when "001110"

                =>  M_TYPE <= "0100";

                    M_LIT_LENGTH <= "01111";

                        SELECT_MOVE <= "100";

                        RL_DETECTED <= '0';

    when "001101"

                =>  M_TYPE <= "1001";

                    M_LIT_LENGTH <= "10111";

                        SELECT_MOVE <= "101";

                        RL_DETECTED <= '0';

    when "001100"

                =>  M_TYPE <= "1100";

                    M_LIT_LENGTH <= "10111";

                        SELECT_MOVE <= "101";

                        RL_DETECTED <= '0';

    when others

                =>  M_TYPE <= "1111";

                    M_LIT_LENGTH <= "00000";

                        SELECT_MOVE <= "000";

                        RL_DETECTED <= '0';

end case;

end process TREE_DEC;

end HUFFMAN; -- end of architecture