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       = PARSER_CONCATENATOR     --
--  version      = 1.0                     --
--  last update  = 30/05/00                --
--  author       = Jose Nunez              --
---------------------------------------------
 
 
-- FUNCTION
-- The parser concatenator adds more data when required
 
--  PIN LIST
 
--  DATA_IN_BUFFER  = 32 bits of data comming from the buffer
--  DATA_OLD = old data
--  LENGTH_OLD = old length
--  DATA_NEW = new data negerated
--  LENGTH_OUT = new length generated 
 
library ieee;
use ieee.std_logic_1164.all;
 
entity PARSER_CONCATENATOR is
port
	(
	DATA_IN_BUFFER : in bit_vector(31 downto 0);
	ENABLE: in bit;
	READ : in bit;
	DATA_OLD : in bit_vector(55 downto 0);
	LENGTH_OLD : in bit_vector(2 downto 0);
	DATA_NEW : out bit_vector(55 downto 0);
	LENGTH_NEW : out bit_vector(2 downto 0)
	);
end PARSER_CONCATENATOR;
 
architecture STRUCTURAL of PARSER_CONCATENATOR is
 
begin
 
LENGTH_CALC : process(LENGTH_OLD,ENABLE, READ)
 
begin
 
if (ENABLE = '1' and READ = '1') then
   case LENGTH_OLD is
	   	when "011" => LENGTH_NEW <= "111";
		when "010" => LENGTH_NEW <= "110";
   	    when "001" => LENGTH_NEW <= "101";
		when "000" => LENGTH_NEW <= "100";
		when others => LENGTH_NEW <= LENGTH_OLD;
   end case;
else
	LENGTH_NEW <= LENGTH_OLD;
end if;
 
end process LENGTH_CALC;
 
 
CODE_CALC : process(LENGTH_OLD , DATA_IN_BUFFER , DATA_OLD)
 
begin
 
case LENGTH_OLD is
    when "000" => DATA_NEW(55 downto 0)  <= DATA_IN_BUFFER & "000000000000000000000000";
    when "001" => DATA_NEW(55 downto 0)  <= DATA_OLD(55 downto 48) & DATA_IN_BUFFER &  "0000000000000000";
    when "010" => DATA_NEW(55 downto 0)  <= DATA_OLD(55 downto 40) & DATA_IN_BUFFER & "00000000";
    when "011" => DATA_NEW(55 downto 0)  <= DATA_OLD(55 downto 32) & DATA_IN_BUFFER;
    when others   => DATA_NEW(55 downto 0) <= DATA_OLD(55 downto 0);
end case;
 
end process CODE_CALC;
 
end STRUCTURAL;