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       = FULL_MATCH_D            --

--  version      = 1.0                     --

--  last update  = 3/06/01                 --

--  author       = Jose Nunez              --

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

-- FUNCTION

-- the full match detection unit detects a full match with the same length for movement generation

-- PIN LIST

-- PRIORITY_6 : 4 bytes match

-- PRIORITY_5 : 3 bytes match

-- PRIORITY_2 : 2 bytes match

-- SAME_LENGTH_2 : detect the same length of 2 search and present

-- SAME_LENGTH_3 : detect the same length of 3 search and present

-- SAME_LENGTH_4 : detect the same length of 4 search and present

-- FULL_MATCH_VECTOR : output with only one bit set to 1 for full match with same length

library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

library dzx;

use dzx.bit_utils.all;

entity FULL_MATCH_D is

port (

                  NFL_M_ONE : in bit_vector(7 downto 0); --control how many locations are active

                  MOVE_ENABLE : in bit;

       PRIORITY_6: in bit_vector(15 downto 0);

                  PRIORITY_5: in bit_vector(15 downto 0);

                  PRIORITY_2: in bit_vector(15 downto 0);

                  SAME_LENGTH_2: in bit_vector(15 downto 0);

                  SAME_LENGTH_3: in bit_vector(15 downto 0);

                  SAME_LENGTH_4: in bit_vector(15 downto 0);

                  CLK : in bit;

                  CLEAR : in bit;

                  RESET : in bit;

                  FULL_MATCH : out bit;

                  FULL_MATCH_AT_ZERO : out bit;

                  SAME_POSITION : out bit;

                  FULL_MATCH_VECTOR : out bit_vector(15 downto 0)

          );

end FULL_MATCH_D;

architecture STRUCTURAL of FULL_MATCH_D is

signal FULL_MATCH_VECTOR_aux : bit_vector(15 downto 0);

signal FULL_MATCH_VECTOR_old : bit_vector(15 downto 0);

signal NOR_ARRAY :  bit_vector(15 downto 0);

begin

FULL_MATCH_VECTOR_aux <= (SAME_LENGTH_4 and PRIORITY_6) or (SAME_LENGTH_3 and PRIORITY_5) or (SAME_LENGTH_2 and PRIORITY_2);

FULL_MATCH <= or_bits(FULL_MATCH_VECTOR_aux);

FULL_MATCH_AT_ZERO <= FULL_MATCH_VECTOR_aux(15) and FULL_MATCH_VECTOR_old(15);

FULL_MATCH_VECTOR <= FULL_MATCH_VECTOR_aux;

-- we need to store the old full match vector to know if a new full match is detected in the same position

LOCATE_SAME_POSITION : process(CLK, CLEAR)

begin

if (CLEAR = '0') then

        FULL_MATCH_VECTOR_old <= x"0000";

elsif (CLK'event and CLK = '1') then

        if(RESET = '0') then

                FULL_MATCH_VECTOR_old <= x"0000";

        elsif ( MOVE_ENABLE = '0') then

                FULL_MATCH_VECTOR_old <= FULL_MATCH_VECTOR_aux;

  else

                FULL_MATCH_VECTOR_old <= FULL_MATCH_VECTOR_old;

        end if;

end if;

end process;

VERIFY_SAME_POSITION : process(FULL_MATCH_VECTOR_old,FULL_MATCH_VECTOR_aux,NFL_M_ONE)

variable NFL_INT : integer range 0 to 15;

begin

NFL_INT := to_integer(unsigned(to_stdlogicvector(NFL_M_ONE)));

for i in 15 downto 0 loop -- 16 location dictionary

  if i >= (15-NFL_INT) then

                NOR_ARRAY(i) <= FULL_MATCH_VECTOR_old(i) xor FULL_MATCH_VECTOR_aux(i);

        else

                NOR_ARRAY(i) <= '0';

        end if;

end loop;

end process;

SAME_POSITION <= nor_bits(NOR_ARRAY);

--SAME_POSITION <= nor_bits(FULL_MATCH_VECTOR_old xor FULL_MATCH_VECTOR_aux);

end STRUCTURAL;