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       = ASSEMBLER     --

--  version      = 2.0           --

--  last update  = 6/06/01       --

--  author       = Jose Nunez    --

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

-- FUNCTION

-- assembler for the uncompressed data.

-- PIN LIST

-- DATA_IN      = uncompressed data from the engine

-- MASK                 = 4 bit indicating which bytes are valid

-- WRITE_OLD    = write operation done shift out used data

-- DATA_OLD             = 56 bits of old data

-- LENGTH_OLD   = length of old data

-- WRITE_NEW    = write data to buffer

-- DATA_NEW     = 56 bits of new data

-- LENGTH_NEW   = length of new data

library ieee,dzx;

use ieee.std_logic_1164.all;

use dzx.bit_arith.all;

use dzx.bit_utils.all;

use dzx.attributes.all;

entity ASSEMBLER is

port

(

        ENABLE : in bit;

    DATA_IN : in bit_vector(31 downto 0);

        MASK_IN : in bit_vector(3 downto 0);

        DATA_OLD : in bit_vector(55 downto 0);

        LENGTH_OLD : in bit_vector(2 downto 0); --only 7 bytes

        DATA_NEW : out bit_vector(55 downto 0);

        LENGTH_NEW : out bit_vector(2 downto 0);

        WRITE : out bit

);

end ASSEMBLER;

architecture ASSEMBLE2 of ASSEMBLER is

begin

CALCULATE_LENGTH : process(ENABLE, MASK_IN, LENGTH_OLD)

variable TEMP_LENGTH : bit_vector(2 downto 0);

begin

TEMP_LENGTH := LENGTH_OLD;

if(TEMP_LENGTH(2) = '1') then

         TEMP_LENGTH(2) := '0';

end if;

if (ENABLE = '0') then

        case MASK_IN is

        when "1000" =>

                TEMP_LENGTH := TEMP_LENGTH + "001";

        when "1100" =>

                TEMP_LENGTH := TEMP_LENGTH + "010";

        when "1110" =>

                TEMP_LENGTH := TEMP_LENGTH + "011";

        when "1111" =>

                TEMP_LENGTH := TEMP_LENGTH + "100";

        when others =>

                TEMP_LENGTH := TEMP_LENGTH;

        end case;

else

        TEMP_LENGTH := TEMP_LENGTH;

end if;

WRITE <= TEMP_LENGTH(2);

LENGTH_NEW <= TEMP_LENGTH;

end process CALCULATE_LENGTH;

CONCATENATE_DATA : process(DATA_OLD, DATA_IN, LENGTH_OLD)

begin

        case LENGTH_OLD is

        when "000" => DATA_NEW <= DATA_IN & x"000000";

        when "001" => DATA_NEW <= DATA_OLD(55 downto 48) & DATA_IN & x"0000";

        when "010" => DATA_NEW <= DATA_OLD(55 downto 40) & DATA_IN & x"00";

        when "011" => DATA_NEW <= DATA_OLD(55 downto 32) & DATA_IN;

        when "100" => DATA_NEW <= DATA_IN & x"000000";

        when "101" => DATA_NEW <= DATA_OLD(23 downto 16) & DATA_IN & x"0000";

        when "110" => DATA_NEW <= DATA_OLD(23 downto 8) & DATA_IN & x"00";

        when "111" => DATA_NEW <= DATA_OLD(23 downto 0) & DATA_IN;

        end case;

end process CONCATENATE_DATA;

end ASSEMBLE2; -- end of architecture