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gajos |
-----------------------------------------------------------------------
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---- ----
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---- Present - a lightweight block cipher project ----
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---- ----
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---- This file is part of the Present - a lightweight block ----
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---- cipher project ----
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---- http://www.http://opencores.org/project,present ----
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---- ----
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---- Description: ----
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---- State machine for Present decoder. It controls entire ----
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---- environment for decoding. We can feature 2 'steady states' ----
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---- and 2 'running states'. For more informations see below ----
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---- To Do: ----
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---- ----
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---- Author(s): ----
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---- - Krzysztof Gajewski, gajos@opencores.org ----
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---- k.gajewski@gmail.com ----
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---- ----
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-----------------------------------------------------------------------
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---- ----
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---- Copyright (C) 2013 Authors and OPENCORES.ORG ----
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---- ----
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---- This source file may be used and distributed without ----
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---- restriction provided that this copyright statement is not ----
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---- removed from the file and that any derivative work contains ----
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---- the original copyright notice and the associated disclaimer. ----
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---- ----
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---- This source file is free software; you can redistribute it ----
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---- and-or modify it under the terms of the GNU Lesser General ----
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---- Public License as published by the Free Software Foundation; ----
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---- either version 2.1 of the License, or (at your option) any ----
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---- later version. ----
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---- ----
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---- This source is distributed in the hope that it will be ----
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---- useful, but WITHOUT ANY WARRANTY; without even the implied ----
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---- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ----
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---- PURPOSE. See the GNU Lesser General Public License for more ----
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---- details. ----
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---- ----
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---- You should have received a copy of the GNU Lesser General ----
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---- Public License along with this source; if not, download it ----
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---- from http://www.opencores.org/lgpl.shtml ----
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---- ----
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-----------------------------------------------------------------------
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gajos |
library IEEE;
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use IEEE.STD_LOGIC_1164.ALL;
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use work.kody.ALL;
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-- Uncomment the following library declaration if using
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-- arithmetic functions with Signed or Unsigned values
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--use IEEE.NUMERIC_STD.ALL;
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-- Uncomment the following library declaration if instantiating
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-- any Xilinx primitives in this code.
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--library UNISIM;
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--use UNISIM.VComponents.all;
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entity FullDecoderSM is
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port(
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key_gen_start : out std_logic;
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key_gen_ready : in std_logic;
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decode_start : out std_logic;
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decode_ready : in std_logic;
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full_decoder_start :in std_logic;
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full_decoder_ready : out std_logic;
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clk, reset :in std_logic
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);
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end FullDecoderSM;
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architecture Behavioral of FullDecoderSM is
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signal state : decode_states;
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signal next_state : decode_states;
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begin
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states : process(state, full_decoder_start, key_gen_ready, decode_ready)
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begin
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case state is
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gajos |
---- It is No operation - waiting for proper data in the input ----
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gajos |
when NOP =>
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key_gen_start <= '0';
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decode_start <= '0';
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full_decoder_ready <= '0';
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if (full_decoder_start = '1') then
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next_state <= KG_START;
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else
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next_state <= NOP;
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end if;
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gajos |
---- It is running key generator for decoding
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gajos |
when KG_START =>
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key_gen_start <= '1';
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decode_start <= '0';
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full_decoder_ready <= '0';
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if (key_gen_ready = '1') then
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next_state <= DEC_START;
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else
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next_state <= KG_START;
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end if;
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---- enerated key for decoding is ready. Now we are decoding ----
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when DEC_START =>
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key_gen_start <= '1';
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decode_start <= '1';
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full_decoder_ready <= '0';
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if (decode_ready = '1') then
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next_state <= DEC_READY;
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else
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next_state <= DEC_START;
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end if;
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gajos |
---- Decoding was ended. Waiting for user retrieving data ----
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---- and give information about new operation ----
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gajos |
when DEC_READY =>
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key_gen_start <= '1';
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decode_start <= '1';
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full_decoder_ready <= '1';
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if (full_decoder_start = '1') then
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next_state <= DEC_READY;
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else
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next_state <= NOP;
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end if;
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end case;
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end process states;
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SM : process (clk, reset)
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begin
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if (reset = '1') then
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state <= NOP;
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elsif (clk'Event and clk = '1') then
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state <= next_state;
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end if;
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end process SM;
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end Behavioral;
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