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       = OB_ASSEM    --

--  version      = 1.0         --

--  last update  = 19/05/98    --

--  author       = Jose Nunez  --

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

-- FUNCTION

-- Assembles output tuples according to the 4 bit MATCH_TYPE

-- If bit N of MATCH_TYPE is LOW then byte A of CAM_DATA is

-- valid and should be output to byte A of DOUT, otherwise

-- byte A of LITERAL_DATA should be output to DOUT.

-- This is effectively 4 X (8 X 2-to-1 MUX).

-- PIN LIST

-- CAM_DATA     =  32 bit data from the CAM array

-- LITERAL_DATA =  32 bits of literal data

-- MATCH_TYPE   =  4 bit bus to indicate which BYTES of

--                  CAM_DATA are valid

-- DOUT         =  output of 32 bits of valid data

library ieee,dzx;

use ieee.std_logic_1164.all;

use dzx.attributes.all;

entity OB_ASSEM is

port

(

      RAM_DATA : in std_logic_vector(31 downto 0) ;

          RAM_MASK : in std_logic_vector(3 downto 0);

      LITERAL_DATA : in bit_vector(31 downto 0);

          LITERAL_MASK : in bit_vector(4 downto 0);

      MATCH_TYPE : in bit_vector(3 downto 0) ;

          MOUT : out bit_vector(3 downto 0);

      DOUT : out bit_vector(31 downto 0)

);

end OB_ASSEM;

architecture ASSEMBLE of OB_ASSEM is

signal CAM_DATA : bit_vector(31 downto 0);

signal MISS_DATA : bit_vector(31 downto 0);

begin

CAM_DATA <= To_bitvector(RAM_DATA);

MISS_ASSEMBLE : process(LITERAL_MASK, LITERAL_DATA)

begin

case LITERAL_MASK is

 when "10000" => MISS_DATA <= x"20000000";

 when "11000" => MISS_DATA <= LITERAL_DATA(31 downto 24) & x"200000";

 when "11100" => MISS_DATA <= LITERAL_DATA(31 downto 24) & LITERAL_DATA(23 downto 16) & x"2000";

 when "11110" => MISS_DATA <= LITERAL_DATA(31 downto 24) & LITERAL_DATA(23 downto 16) & LITERAL_DATA(15 downto 8) & x"20";

 when "11111" => MISS_DATA <= LITERAL_DATA(31 downto 24) & LITERAL_DATA(23 downto 16) & LITERAL_DATA(15 downto 8) & LITERAL_DATA(7 downto 0);

 when others => MISS_DATA <= x"00000000";

end case;

end process MISS_ASSEMBLE;

DECIDE : process (CAM_DATA , RAM_MASK, LITERAL_DATA , MATCH_TYPE, MISS_DATA, LITERAL_MASK)

begin

case MATCH_TYPE is

        when "0000" =>  DOUT(31 downto 24) <= CAM_DATA(31 downto 24);

                        DOUT(23 downto 16) <= CAM_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= CAM_DATA(15 downto 8);

                        DOUT(7 downto 0)   <= CAM_DATA(7 downto 0);

                        MOUT <= To_bitvector(RAM_MASK);

        when "0001" =>  DOUT(31 downto 24) <= CAM_DATA(31 downto 24);

                        DOUT(23 downto 16) <= CAM_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= CAM_DATA(15 downto 8);

                        DOUT(7 downto 0)   <= LITERAL_DATA(31 downto 24);

                        MOUT <= "1111";

        when "0010" =>  DOUT(31 downto 24) <= CAM_DATA(31 downto 24);

                        DOUT(23 downto 16) <= CAM_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= LITERAL_DATA(31 downto 24);

                        DOUT(7 downto 0)   <= CAM_DATA(7 downto 0);

                        MOUT <= "1111";

        when "0011" =>  DOUT(31 downto 24) <= CAM_DATA(31 downto 24);

                        DOUT(23 downto 16) <= CAM_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= LITERAL_DATA(31 downto 24);

                        DOUT(7 downto 0)   <= LITERAL_DATA(23 downto 16);

                        MOUT <= "1111";

        when "0100" =>  DOUT(31 downto 24) <= CAM_DATA(31 downto 24);

                        DOUT(23 downto 16) <= LITERAL_DATA(31 downto 24);

                        DOUT(15 downto 8)  <= CAM_DATA(15 downto 8);

                        DOUT(7 downto 0)   <= CAM_DATA(7 downto 0);

                        MOUT <= "1111";

        when "0110" =>  DOUT(31 downto 24) <= CAM_DATA(31 downto 24);

                        DOUT(23 downto 16) <= LITERAL_DATA(31 downto 24);

                        DOUT(15 downto 8)  <= LITERAL_DATA(23 downto 16);

                        DOUT(7 downto 0)   <= CAM_DATA(7 downto 0);

                        MOUT <= "1111";

        when "1000" =>  DOUT(31 downto 24) <= LITERAL_DATA(31 downto 24);

                        DOUT(23 downto 16) <= CAM_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= CAM_DATA(15 downto 8);

                        DOUT(7 downto 0)   <= CAM_DATA(7 downto 0);

                        MOUT <= "1111";

        when "1001" =>  DOUT(31 downto 24) <= LITERAL_DATA(31 downto 24);

                        DOUT(23 downto 16) <= CAM_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= CAM_DATA(15 downto 8);

                        DOUT(7 downto 0)   <= LITERAL_DATA(23 downto 16);

                        MOUT <= "1111";

        when "1100" =>  DOUT(31 downto 24) <= LITERAL_DATA(31 downto 24);

                        DOUT(23 downto 16) <= LITERAL_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= CAM_DATA(15 downto 8);

                        DOUT(7 downto 0)   <= CAM_DATA(7 downto 0);

                        MOUT <= "1111";

        when "1111" =>  DOUT(31 downto 24) <= MISS_DATA(31 downto 24);

                        DOUT(23 downto 16) <= MISS_DATA(23 downto 16);

                        DOUT(15 downto 8)  <= MISS_DATA(15 downto 8);

                        DOUT(7 downto 0)   <= MISS_DATA(7 downto 0);

                MOUT <= LITERAL_MASK(4 downto 1);

        when others => DOUT(31 downto 24) <= "00000000";

                        DOUT(23 downto 16) <= "00000000";

                        DOUT(15 downto 8)  <= "00000000";

                        DOUT(7 downto 0)   <= "00000000";

                MOUT <= "0000";

end case;

end process DECIDE;

end ASSEMBLE;