Subversion Repositories apbtoaes128

//////////////////////////////////////////////////////////////////

////

////

////    AES CORE BLOCK

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////

////

//// This file is part of the APB to I2C project

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//// http://www.opencores.org/cores/apbi2c/

////

////

////

//// Description

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//// Implementation of APB IP core according to

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//// aes128_spec IP core specification document.

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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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//// Author(s): - Felipe Fernandes Da Costa, fefe2560@gmail.com

////              Julio Cesar 

////

///////////////////////////////////////////////////////////////// 

////

////

//// Copyright (C) 2009 Authors and OPENCORES.ORG

////

////

////

//// This source file may be used and distributed without

////

//// restriction provided that this copyright statement is not

////

//// removed from the file and that any derivative work contains

//// the original copyright notice and the associated disclaimer.

////

////

//// This source file 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 source 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 source; if not, download it

////

//// from http://www.opencores.org/lgpl.shtml

////

////

///////////////////////////////////////////////////////////////////

module shift_rows

(

        //OUTPUTS

        output [127 : 0] data_out_enc,  // Result after Shift Rows operation - enc

        output [127 : 0] data_out_dec,  // Result after Shift Rows operation - dec

        //INPUTS

        input  [127 : 0] data_in        // Input Bus

);

localparam integer BUS_WIDTH = 128;  // Bus Width

localparam integer ST_WORD   =   8;  // Data Size of word in State MAtrix

localparam integer ST_LINE   =   4;  // Number of Lines of State Matrix

localparam integer ST_COL    =   4;  // Number of Columns of State Matrix

wire [ST_WORD - 1 : 0] state[0 : ST_LINE - 1][0 : ST_COL - 1];

wire [ST_WORD - 1 : 0] state_sft_l[0 : ST_LINE - 1][0 : ST_COL - 1];

wire [ST_WORD - 1 : 0] state_sft_r[0 : ST_LINE - 1][0 : ST_COL - 1];

//=====================================================================================

// State Matrix generation

//=====================================================================================

generate

        genvar l,c;

        for(l = 0; l < ST_LINE; l = l + 1)

                for(c = 0; c < ST_COL; c = c + 1)

                        assign state[l][c] = data_in[ST_WORD*((ST_COL - c)*ST_LINE - l) - 1 : ST_WORD*((ST_COL - c)*ST_LINE - l - 1)];

endgenerate

//=====================================================================================

// Shift Row operation

//=====================================================================================

generate

        genvar l1,c1;

        for(l1 = 0; l1 < ST_LINE; l1 = l1 + 1)

                for(c1 = 0; c1 < ST_COL; c1 = c1 + 1)

                        begin

                                assign state_sft_l[l1][c1] = state[l1][(c1 + l1)%ST_COL];

                                assign state_sft_r[l1][c1] = state[l1][(c1 + (ST_COL - l1))%ST_COL];

                        end

endgenerate

//=====================================================================================

// State Matrix to Bus Output Transformation

//=====================================================================================

generate

        genvar l2,c2;

        for(l2 = 0; l2 < ST_LINE; l2 = l2 + 1)

                for(c2 = 0; c2 < ST_COL; c2 = c2 + 1)

                        begin

                                assign data_out_enc[ST_WORD*((ST_COL - c2)*ST_LINE - l2) - 1 : ST_WORD*((ST_COL - c2)*ST_LINE - l2 - 1)] = state_sft_l[l2][c2];

                                assign data_out_dec[ST_WORD*((ST_COL - c2)*ST_LINE - l2) - 1 : ST_WORD*((ST_COL - c2)*ST_LINE - l2 - 1)] = state_sft_r[l2][c2];

                        end

endgenerate

endmodule