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--This library is free software; you can redistribute it and/or
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--modify it under the terms of the GNU Lesser General Public
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--License as published by the Free Software Foundation; either
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--version 2.1 of the License, or (at your option) any later version.
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--This library is distributed in the hope that it will be useful,
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--but WITHOUT ANY WARRANTY; without even the implied warranty of
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--MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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--Lesser General Public License for more details.
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--You should have received a copy of the GNU Lesser General Public
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--License along with this library; if not, write to the Free Software
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--Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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-- e_mail : j.l.nunez-yanez@byacom.co.uk
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---------------------------------------------
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-- ENTITY = FULL_MATCH_D --
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-- version = 1.0 --
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-- last update = 3/06/01 --
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-- author = Jose Nunez --
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---------------------------------------------
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-- FUNCTION
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-- the full match detection unit detects a full match with the same length for movement generation
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-- PIN LIST
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-- PRIORITY_6 : 4 bytes match
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-- PRIORITY_5 : 3 bytes match
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-- PRIORITY_2 : 2 bytes match
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-- SAME_LENGTH_2 : detect the same length of 2 search and present
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-- SAME_LENGTH_3 : detect the same length of 3 search and present
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-- SAME_LENGTH_4 : detect the same length of 4 search and present
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-- FULL_MATCH_VECTOR : output with only one bit set to 1 for full match with same length
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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library dzx;
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use dzx.bit_utils.all;
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entity FULL_MATCH_D is
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port (
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NFL_M_ONE : in bit_vector(7 downto 0); --control how many locations are active
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MOVE_ENABLE : in bit;
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PRIORITY_6: in bit_vector(15 downto 0);
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PRIORITY_5: in bit_vector(15 downto 0);
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PRIORITY_2: in bit_vector(15 downto 0);
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SAME_LENGTH_2: in bit_vector(15 downto 0);
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SAME_LENGTH_3: in bit_vector(15 downto 0);
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SAME_LENGTH_4: in bit_vector(15 downto 0);
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CLK : in bit;
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CLEAR : in bit;
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RESET : in bit;
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FULL_MATCH : out bit;
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FULL_MATCH_AT_ZERO : out bit;
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SAME_POSITION : out bit;
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FULL_MATCH_VECTOR : out bit_vector(15 downto 0)
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);
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end FULL_MATCH_D;
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architecture STRUCTURAL of FULL_MATCH_D is
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signal FULL_MATCH_VECTOR_aux : bit_vector(15 downto 0);
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signal FULL_MATCH_VECTOR_old : bit_vector(15 downto 0);
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signal NOR_ARRAY : bit_vector(15 downto 0);
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signal FULL_MATCH_aux : bit;
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begin
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FULL_MATCH_VECTOR_aux <= (SAME_LENGTH_4 and PRIORITY_6) or (SAME_LENGTH_3 and PRIORITY_5) or (SAME_LENGTH_2 and PRIORITY_2);
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FULL_MATCH_aux <= or_bits(FULL_MATCH_VECTOR_aux);
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FULL_MATCH <= FULL_MATCH_aux;
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FULL_MATCH_AT_ZERO <= FULL_MATCH_VECTOR_aux(15) and FULL_MATCH_VECTOR_old(15);
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FULL_MATCH_VECTOR <= FULL_MATCH_VECTOR_aux;
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-- we need to store the old full match vector to know if a new full match is detected in the same position
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LOCATE_SAME_POSITION : process(CLK, CLEAR)
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begin
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if (CLEAR = '0') then
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FULL_MATCH_VECTOR_old <= x"0000";
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elsif (CLK'event and CLK = '1') then
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if(RESET = '0') then
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FULL_MATCH_VECTOR_old <= x"0000";
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elsif ( MOVE_ENABLE = '0') then
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FULL_MATCH_VECTOR_old <= FULL_MATCH_VECTOR_aux;
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else
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FULL_MATCH_VECTOR_old <= FULL_MATCH_VECTOR_old;
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end if;
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end if;
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end process;
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VERIFY_SAME_POSITION : process(FULL_MATCH_VECTOR_old,FULL_MATCH_VECTOR_aux,NFL_M_ONE)
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variable NFL_INT : integer range 0 to 15;
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begin
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NFL_INT := to_integer(unsigned(to_stdlogicvector(NFL_M_ONE)));
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for i in 15 downto 0 loop -- 16 location dictionary
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if i >= (15-NFL_INT) then
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NOR_ARRAY(i) <= FULL_MATCH_VECTOR_old(i) xor FULL_MATCH_VECTOR_aux(i);
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else
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NOR_ARRAY(i) <= '0';
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end if;
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end loop;
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end process;
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SAME_POSITION <= nor_bits(NOR_ARRAY) when FULL_MATCH_aux = '1' else '0';
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--SAME_POSITION <= nor_bits(FULL_MATCH_VECTOR_old xor FULL_MATCH_VECTOR_aux);
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end STRUCTURAL;
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