Subversion Repositories avs_aes

------------------------------------------------------------------------------

-- This file is part of the project      avs_aes

-- see: http://opencores.org/project,avs_aes

--

-- description: 

-- Sbox implements a lookup ROM for nonlinear substitution of a Bytearray.

-- This is only the entity for either arch1 (which is pure VHDL) or M4K which

-- is an Altera M4K-Blockram implementation.

--

-------------------------------------------------------------------------------!

--

-- Author(s):

--         Thomas Ruschival -- ruschi@opencores.org (www.ruschival.de)

--

--------------------------------------------------------------------------------

-- Copyright (c) 2009, Authors and opencores.org

-- All rights reserved.

--

-- Redistribution and use in source and binary forms, with or without modification,

-- are permitted provided that the following conditions are met:

--        * Redistributions of source code must retain the above copyright notice,

--        this list of conditions and the following disclaimer.

--        * Redistributions in binary form must reproduce the above copyright notice,

--        this list of conditions and the following disclaimer in the documentation

--        and/or other materials provided with the distribution.

--        * Neither the name of the organization nor the names of its contributors

--        may be used to endorse or promote products derived from this software without

--        specific prior written permission.

-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

-- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,

-- OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

-- THE POSSIBILITY OF SUCH DAMAGE

-------------------------------------------------------------------------------

-- version management:

-- $Author::                                         $

-- $Date::                                           $

-- $Revision::                                       $

-------------------------------------------------------------------------------

library ieee;

use ieee.std_logic_1164.all;

-------------------------------------------------------------------------------

-- The interface is 2x8Bit because Altera megafunction is supposed to be at max

-- 8Bit dual port ROM (and I relied on a altera quartus generated component

-- before) see architecture m4k

-------------------------------------------------------------------------------

entity sbox is

        generic (

                INVERSE : BOOLEAN := false              -- is this the inverse or the forward

                                                                                -- lookup table.

                                                                                -- TRUE -> inverse sbox

                                                                                -- FALSE -> forward sbox

                );

        port(

                clk               : in  STD_LOGIC;              -- system clock

                address_a : in  STD_LOGIC_VECTOR (7 downto 0);   -- 1st byte

                address_b : in  STD_LOGIC_VECTOR (7 downto 0);   -- 2nd byte

                q_a               : out STD_LOGIC_VECTOR (7 downto 0);   -- substituted 1st byte

                q_b               : out STD_LOGIC_VECTOR (7 downto 0)    -- substituted 2nd byte

                );

end sbox;