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       = ENCODE16_4 --

--  version      = 2.0         --

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

--  author       = Jose Nunez  --

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

-- FUNCTION

-- 16 to 4 encoder to convert active low 16 bit maatch bus input

-- to a 4 bit wide binary code.

--  PIN LIST

--  MATCH_LOC_IN  = 16 bit match location input bus (active low)

--  MATCH_LOC_OUT = 4 bit binary output match location bus

--  MISS          = active low signal to indicate that a miss has occurred

library ieee,dzx;

use ieee.std_logic_1164.all;

entity ENCODE16_4 is

port

(

        MATCH_LOC_IN : in bit_vector(15 downto 0);

        MATCH_LOC_OUT : out bit_vector(3 downto 0)

);

end ENCODE16_4;

architecture ENC2 of ENCODE16_4 is

begin

ENCODER : process (MATCH_LOC_IN)

begin

case MATCH_LOC_IN is

    when  x"FFFE" => MATCH_LOC_OUT <= "0000";

    when  x"FFFD" => MATCH_LOC_OUT <= "0001";

    when  x"FFFB" => MATCH_LOC_OUT <= "0010";

    when  x"FFF7" => MATCH_LOC_OUT <= "0011";

    when  x"FFEF" => MATCH_LOC_OUT <= "0100";

    when  x"FFDF" => MATCH_LOC_OUT <= "0101";

    when  x"FFBF" => MATCH_LOC_OUT <= "0110";

    when  x"FF7F" => MATCH_LOC_OUT <= "0111";

    when  x"FEFF" => MATCH_LOC_OUT <= "1000";

    when  x"FDFF" => MATCH_LOC_OUT <= "1001";

    when  x"FBFF" => MATCH_LOC_OUT <= "1010";

    when  x"F7FF" => MATCH_LOC_OUT <= "1011";

    when  x"EFFF" => MATCH_LOC_OUT <= "1100";

    when  x"DFFF" => MATCH_LOC_OUT <= "1101";

    when  x"BFFF" => MATCH_LOC_OUT <= "1110";

    when  x"7FFF" => MATCH_LOC_OUT <= "1111";

    when  x"FFFF" => MATCH_LOC_OUT <= "1111";

    when others => MATCH_LOC_OUT <= "1111";

    -- when others => null;

end case;

end process ENCODER;

end ENC2; -- end of architecture