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       = MAX_PBC_LENGTH          --

--  version      = 1.0                     --

--  last update  = 20/07/01                 --

--  author       = Jose Nunez              --

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

-- FUNCTION

-- produces two possible start for the match type code depending on the PBC code

--  PIN LIST

--  NFL_MINUS_ONE = next free location minus one

--  CODE = all the bits that can contain match location plus match type code

--  POS_MT_K_1 = match type when using k-1 bits

--  POS_MT_K = match type when using k bits

library ieee,dzx;

use ieee.std_logic_1164.all;

use dzx.bit_arith.all;

entity LENGTH_SELECTION_2 is

port (MATCH_LOC_K : in bit_vector(3 downto 0);

          MATCH_LOC_K_1 : in bit_vector(3 downto 0);

          SUB : in bit_vector(4 downto 0);

          MAX_MATCH_LENGTH : in bit_vector(2 downto 0);

          MATCH_LENGTH : out bit_vector(2 downto 0);

          SEL_MATCH_LOC : out bit_vector(3 downto 0);

          K_BITS: out bit

         );

end LENGTH_SELECTION_2;

architecture STRUCTURAL of LENGTH_SELECTION_2 is

begin

SEL : process(SUB, MATCH_LOC_K, MATCH_LOC_K_1, MAX_MATCH_LENGTH)

variable MATCH_LOC_TEMP : bit_vector(4 downto 0);

begin

        MATCH_LOC_TEMP := '0' & MATCH_LOC_K - SUB;

        if ( '0' & MATCH_LOC_K_1 < SUB) then

                K_BITS <= '0';

                MATCH_LENGTH <= MAX_MATCH_LENGTH - "001";

                SEL_MATCH_LOC <= MATCH_LOC_K_1;

        else

                K_BITS <= '1';

                MATCH_LENGTH <= MAX_MATCH_LENGTH;

                SEL_MATCH_LOC <= MATCH_LOC_TEMP(3 downto 0);

        end if;

end process SEL;

end STRUCTURAL;