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