Subversion Repositories apbtoaes128

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

////

////

////    AES CORE BLOCK

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////

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//// This file is part of the APB to AES128 project

////

//// http://www.opencores.org/cores/apbtoaes128/

////

////

////

//// 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 data_swap

#(

        parameter WIDTH = 32

)(

        //OUTPUTS

        output [WIDTH - 1:0] data_swap,

        //INPUTS

        input  [WIDTH - 1:0] data_in,

        input  [ 1:0] swap_type

);

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

// Swap Types

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

localparam NO_SWAP        = 2'b00;

localparam HALF_WORD_SWAP = 2'b01;

localparam BYTE_SWAP      = 2'b10;

localparam BIT_SWAP       = 2'b11;

localparam TYPES = 4;

wire [WIDTH - 1 : 0] words[0 : TYPES - 1];

generate

        genvar i, j;

        for(i = 0; i < TYPES; i = i + 1)

                for(j = 0; j < WIDTH; j = j + 1)

                        begin

                                if(i != 3)

                                        assign words[i][j] = data_in[(WIDTH - (WIDTH/2**i)) - 2*(WIDTH/2**i)*(j/(WIDTH/2**i)) + j];

                                else

                                        assign words[i][j] = data_in[WIDTH - 1 - j];

                        end

endgenerate

assign data_swap = words[swap_type];

endmodule