--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 = FULL_MATCH_D --
-- version = 1.0 --
-- last update = 3/06/01 --
-- author = Jose Nunez --
---------------------------------------------
-- FUNCTION
-- the full match detection unit detects a full match with the same length for movement generation
-- PIN LIST
-- PRIORITY_6 : 4 bytes match
-- PRIORITY_5 : 3 bytes match
-- PRIORITY_2 : 2 bytes match
-- SAME_LENGTH_2 : detect the same length of 2 search and present
-- SAME_LENGTH_3 : detect the same length of 3 search and present
-- SAME_LENGTH_4 : detect the same length of 4 search and present
-- FULL_MATCH_VECTOR : output with only one bit set to 1 for full match with same length
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library dzx;
use dzx.bit_utils.all;
entity FULL_MATCH_D is
port (
NFL_M_ONE : in bit_vector(7 downto 0); --control how many locations are active
MOVE_ENABLE : in bit;
PRIORITY_6: in bit_vector(15 downto 0);
PRIORITY_5: in bit_vector(15 downto 0);
PRIORITY_2: in bit_vector(15 downto 0);
SAME_LENGTH_2: in bit_vector(15 downto 0);
SAME_LENGTH_3: in bit_vector(15 downto 0);
SAME_LENGTH_4: in bit_vector(15 downto 0);
CLK : in bit;
CLEAR : in bit;
RESET : in bit;
FULL_MATCH : out bit;
FULL_MATCH_AT_ZERO : out bit;
SAME_POSITION : out bit;
FULL_MATCH_VECTOR : out bit_vector(15 downto 0)
);
end FULL_MATCH_D;
architecture STRUCTURAL of FULL_MATCH_D is
signal FULL_MATCH_VECTOR_aux : bit_vector(15 downto 0);
signal FULL_MATCH_VECTOR_old : bit_vector(15 downto 0);
signal NOR_ARRAY : bit_vector(15 downto 0);
begin
FULL_MATCH_VECTOR_aux <= (SAME_LENGTH_4 and PRIORITY_6) or (SAME_LENGTH_3 and PRIORITY_5) or (SAME_LENGTH_2 and PRIORITY_2);
FULL_MATCH <= or_bits(FULL_MATCH_VECTOR_aux);
FULL_MATCH_AT_ZERO <= FULL_MATCH_VECTOR_aux(15) and FULL_MATCH_VECTOR_old(15);
FULL_MATCH_VECTOR <= FULL_MATCH_VECTOR_aux;
-- we need to store the old full match vector to know if a new full match is detected in the same position
LOCATE_SAME_POSITION : process(CLK, CLEAR)
begin
if (CLEAR = '0') then
FULL_MATCH_VECTOR_old <= x"0000";
elsif (CLK'event and CLK = '1') then
if(RESET = '0') then
FULL_MATCH_VECTOR_old <= x"0000";
elsif ( MOVE_ENABLE = '0') then
FULL_MATCH_VECTOR_old <= FULL_MATCH_VECTOR_aux;
else
FULL_MATCH_VECTOR_old <= FULL_MATCH_VECTOR_old;
end if;
end if;
end process;
VERIFY_SAME_POSITION : process(FULL_MATCH_VECTOR_old,FULL_MATCH_VECTOR_aux,NFL_M_ONE)
variable NFL_INT : integer range 0 to 15;
begin
NFL_INT := to_integer(unsigned(to_stdlogicvector(NFL_M_ONE)));
for i in 15 downto 0 loop -- 16 location dictionary
if i >= (15-NFL_INT) then
NOR_ARRAY(i) <= FULL_MATCH_VECTOR_old(i) xor FULL_MATCH_VECTOR_aux(i);
else
NOR_ARRAY(i) <= '0';
end if;
end loop;
end process;
SAME_POSITION <= nor_bits(NOR_ARRAY);
--SAME_POSITION <= nor_bits(FULL_MATCH_VECTOR_old xor FULL_MATCH_VECTOR_aux);
end STRUCTURAL;
