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[/] [apbtoaes128/] [trunk/] [rtl/] [sBox_8.v] - Blame information for rev 17

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//////////////////////////////////////////////////////////////////
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////
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////
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////    AES CORE BLOCK
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////
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////
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////
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//// This file is part of the APB to I2C project
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////
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//// http://www.opencores.org/cores/apbi2c/
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////
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////
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////
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//// Description
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////
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//// Implementation of APB IP core according to
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////
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//// aes128_spec IP core specification document.
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////
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////
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////
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//// To Do: Things are right here but always all block can suffer changes
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////
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////
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////
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////
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////
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//// Author(s): - Felipe Fernandes Da Costa, fefe2560@gmail.com
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////              Julio Cesar 
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////
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///////////////////////////////////////////////////////////////// 
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////
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////
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//// Copyright (C) 2009 Authors and OPENCORES.ORG
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////
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////
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////
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//// This source file may be used and distributed without
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////
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//// restriction provided that this copyright statement is not
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////
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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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////
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//// This source file is free software; you can redistribute it
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////
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//// and/or modify it under the terms of the GNU Lesser General
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////
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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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////
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//// later version.
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////
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////
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////
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//// This source is distributed in the hope that it will be
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////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied
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////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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////
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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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////
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////
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//// You should have received a copy of the GNU Lesser General
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////
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//// Public License along with this source; if not, download it
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////
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//// from http://www.opencores.org/lgpl.shtml
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////
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////
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///////////////////////////////////////////////////////////////////
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//Reference: A Very Compact Rijndael S-box, D. Canright
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module sBox_8
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(
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  //OUTPUTS
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  output [7:0] sbox_out_enc, // Direct SBOX
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        output [7:0] sbox_out_dec, // Inverse SBOX
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  //INPUTS
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  input  [7:0] sbox_in,
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        input enc_dec,
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        input clk
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);
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//`include "include/sbox_functions.vf"
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// Functions used by SBOX Logic
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// For more detail, see "A Very Compact Rijndael  S-Box" by D. Canright
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localparam ENC = 1;
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localparam DEC = 0;
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function [1:0] gf_sq_2;
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        input [1:0] in;
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        begin
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        gf_sq_2 = {in[0], in[1]};
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        end
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endfunction
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function [1:0] gf_sclw_2;
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        input [1:0] in;
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        begin
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        gf_sclw_2 = {^in, in[1]};
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  end
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endfunction
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function [1:0] gf_sclw2_2;
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        input [1:0] in;
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        begin
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        gf_sclw2_2 = {in[0], ^in};
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  end
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endfunction
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function [1:0] gf_muls_2;
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        input [1:0] in1, in2;
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  input in3, in4;
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        begin
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        gf_muls_2 = ( ~(in1 & in2) ) ^ ( {2{~(in3 & in4)}} );
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  end
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endfunction
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function [1:0] gf_muls_scl_2;
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  input [1:0] in1, in2;
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  input in3, in4;
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        reg [1:0] nand_in1_in2;
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  reg nand_in3_in4;
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        begin
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        nand_in1_in2 = ~(in1 & in2);
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        nand_in3_in4 = ~(in3 & in4);
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        gf_muls_scl_2 = {nand_in3_in4 ^ nand_in1_in2[0], ^nand_in1_in2};
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  end
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endfunction
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function [3:0] gf_inv_4;
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  input [3:0] in;
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        reg [1:0] in_hg;
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        reg [1:0] in_lw;
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        reg [1:0] out_gf_mul_2;
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        reg [1:0] out_gf_mul_3;
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        reg [1:0] out_gf_sq2_3;
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        reg [1:0] in_sq2_3;
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        reg xor_in_hg, xor_in_lw;
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        begin
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                in_hg = in[3:2];
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                in_lw = in[1:0];
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                xor_in_hg = ^in_hg;
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                xor_in_lw = ^in_lw;
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                in_sq2_3 = {~(in_hg[1] | in_lw[1]) ^ (~(xor_in_hg & xor_in_lw)), ~(xor_in_hg | xor_in_lw) ^ (~(in_hg[0] & in_lw[0]))};
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153
        out_gf_sq2_3 = gf_sq_2(in_sq2_3);
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                out_gf_mul_2 = gf_muls_2(out_gf_sq2_3, in_lw, ^out_gf_sq2_3, xor_in_lw);
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                out_gf_mul_3 = gf_muls_2(out_gf_sq2_3, in_hg, ^out_gf_sq2_3, xor_in_hg);
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157
                gf_inv_4 = {out_gf_mul_2, out_gf_mul_3};
158
 end
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endfunction
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function [3:0] gf_sq_scl_4;
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  input [3:0] in;
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        reg [1:0] in_hg;
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        reg [1:0] in_lw;
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        reg [1:0] out_gf_sq2_1;
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        reg [1:0] out_gf_sq2_2;
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        reg [1:0] out_gf_sclw2_1;
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        begin
170
                in_hg = in[3:2];
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                in_lw = in[1:0];
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173
                out_gf_sq2_1 = gf_sq_2(in_hg ^ in_lw );
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                out_gf_sq2_2 = gf_sq_2(in_lw);
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                out_gf_sclw2_1 = gf_sclw_2(out_gf_sq2_2);
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177
                gf_sq_scl_4 = {out_gf_sq2_1, out_gf_sclw2_1};
178
        end
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endfunction
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182
function [3:0] gf_muls_4;
183
  input [3:0] in1;
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  input [3:0] in2;
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        reg [1:0] in1_hg;
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        reg [1:0] in1_lw;
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        reg [1:0] in2_hg;
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        reg [1:0] in2_lw;
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        reg [1:0] xor_in1_hl;
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        reg [1:0] xor_in2_hl;
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        reg [1:0] out_gf_mul_1;
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        reg [1:0] out_gf_mul_2;
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        reg [1:0] out_gf_mul_scl_1;
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        begin
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                in1_hg = in1[3:2];
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                in1_lw = in1[1:0];
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                in2_hg = in2[3:2];
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                in2_lw = in2[1:0];
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                xor_in1_hl = in1_hg ^ in1_lw;
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                xor_in2_hl = in2_hg ^ in2_lw;
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                out_gf_mul_1 = gf_muls_2(in1_hg, in2_hg, in1[3] ^ in1[2], in2[3] ^ in2[2]);
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                out_gf_mul_2 = gf_muls_2(in1_lw, in2_lw, in1[1] ^ in1[0], in2[1] ^ in2[0]);
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                out_gf_mul_scl_1 = gf_muls_scl_2(xor_in1_hl, xor_in2_hl, ^xor_in1_hl, ^xor_in2_hl);
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        gf_muls_4 = {out_gf_mul_1 ^ out_gf_mul_scl_1,  out_gf_mul_2 ^ out_gf_mul_scl_1};
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        end
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endfunction
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function [3:0] gf_inv_8_stage1;
211
  input [7:0] in;
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        reg [3:0] in_hg;
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        reg [3:0] in_lw;
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        reg [3:0] out_gf_mul4_2;
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        reg [3:0] out_gf_mul4_3;
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        reg [3:0] out_gf_inv4_2;
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        reg c1, c2, c3;
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        begin
219
                in_hg = in[7:4];
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                in_lw = in[3:0];
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                c1 = ~((in_hg[3] ^ in_hg[2]) & (in_lw[3] ^ in_lw[2]));
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                c2 = ~((in_hg[2] ^ in_hg[0]) & (in_lw[2] ^ in_lw[0]));
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                c3 = ~((^in_hg) & (^in_lw));
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                gf_inv_8_stage1 =
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                                 {(~((in_hg[2] ^ in_hg[0]) | (in_lw[2] ^ in_lw[0])) ^ (~(in_hg[3] & in_lw[3]))) ^ c1 ^ c3,
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          (~((in_hg[3] ^ in_hg[1]) | (in_lw[3] ^ in_lw[1])) ^ (~(in_hg[2] & in_lw[2]))) ^ c1 ^ c2,
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          (~((in_hg[1] ^ in_hg[0]) | (in_lw[1] ^ in_lw[0])) ^ (~(in_hg[1] & in_lw[1]))) ^ c2 ^ c3,
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          ((~(in_hg[0] | in_lw[0])) ^ (~((in_hg[1] ^ in_hg[0]) & (in_lw[1] ^ in_lw[0])))) ^ (~((in_hg[3] ^ in_hg[1]) & (in_lw[3] ^ in_lw[1]))) ^ c2};
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        end
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endfunction
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function [7:0] gf_inv_8_stage2;
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  input [7:0] in;
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        input [3:0] c;
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        reg [3:0] in_hg;
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        reg [3:0] in_lw;
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        reg [3:0] out_gf_mul4_2;
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        reg [3:0] out_gf_mul4_3;
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        reg [3:0] out_gf_inv4_2;
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        reg c1, c2, c3;
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        begin
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                in_hg = in[7:4];
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                in_lw = in[3:0];
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                out_gf_inv4_2 = gf_inv_4(c);
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                out_gf_mul4_2 = gf_muls_4(out_gf_inv4_2, in_lw);
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                out_gf_mul4_3 = gf_muls_4(out_gf_inv4_2, in_hg);
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                gf_inv_8_stage2 = {out_gf_mul4_2, out_gf_mul4_3};
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        end
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endfunction
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function [15:0] isomorphism;
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  input [7:0] in;
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  reg r1, r2, r3, r4, r5, r6, r7, r8, r9;
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  reg [7:0] enc, dec;
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  begin
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    r1 = in[7]  ^ in[5];
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    r2 = in[7] ~^ in[4];
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    r3 = in[6]  ^ in[0];
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    r4 = in[5] ~^ r3;
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    r5 = in[4]  ^ r4;
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    r6 = in[3]  ^ in[0];
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    r7 = in[2]  ^ r1;
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    r8 = in[1]  ^ r3;
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    r9 = in[3]  ^ r8;
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    enc = {r7 ~^ r8, r5, in[1] ^ r4, r1 ~^ r3, in[1] ^ r2 ^ r6, ~in[0], r4, in[2] ~^ r9};
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    dec = {r2, in[4] ^ r8, in[6] ^ in[4], r9, in[6] ~^ r2, r7, in[4] ^ r6, in[1] ^ r5};
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    isomorphism = {enc, dec};
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  end
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endfunction
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function [7:0] isomorphism_inv;
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  input [7:0] in;
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        input op_type;
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  reg r1, r2, r3, r4, r5, r6, r7, r8, r9, r10;
281
  begin
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    r1  = in[7]  ^ in[3];
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    r2  = in[6]  ^ in[4];
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    r3  = in[6]  ^ in[0];
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    r4  = in[5] ~^ in[3];
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    r5  = in[5] ~^ r1;
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    r6  = in[5] ~^ in[1];
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    r7  = in[4] ~^ r6;
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    r8  = in[2]  ^ r4;
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    r9  = in[1]  ^ r2;
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    r10 = r3     ^ r5;
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                if(op_type == ENC)
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        isomorphism_inv = {r4, r1, r3, r5, r2 ^ r5, r3 ^ r8, r7, r9};
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                else
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        isomorphism_inv = {in[4] ~^ in[1], in[1] ^ r10, in[2] ^ r10, in[6] ~^ in[1], r8 ^ r9, in[7] ~^ r7, r6, ~in[2]};
297
 
298
  end
299
endfunction
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wire [7:0] base_new_enc, base_new_dec, base_new;
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//wire [7:0] base_enc, base_dec;
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wire [3:0] out_gf_inv8_stage1;
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wire [7:0] out_gf_inv8_1;
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//wire [7:0] out_gf_inv8_2;
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reg [3:0] out_gf_pp;
311
reg [7:0] base_new_pp;
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assign {base_new_enc, base_new_dec} = isomorphism(sbox_in);
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315
assign base_new = ~(enc_dec ? base_new_enc : base_new_dec);
316
assign out_gf_inv8_stage1 = gf_inv_8_stage1(base_new);
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318
always @(posedge clk)
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        begin
320
                out_gf_pp <= out_gf_inv8_stage1;
321
                base_new_pp <= base_new;
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        end
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324
assign out_gf_inv8_1 = gf_inv_8_stage2(base_new_pp, out_gf_pp);
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326
assign sbox_out_enc = ~isomorphism_inv(out_gf_inv8_1, ENC);
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assign sbox_out_dec = ~isomorphism_inv(out_gf_inv8_1, DEC);
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endmodule

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