Subversion Repositories reedsolomon

//----------------------------------------------------------------------//

// The MIT License

//

// Copyright (c) 2010 Abhinav Agarwal, Alfred Man Cheuk Ng

// Contact: abhiag@gmail.com

//

// Permission is hereby granted, free of charge, to any person

// obtaining a copy of this software and associated documentation

// files (the "Software"), to deal in the Software without

// restriction, including without limitation the rights to use,

// copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the

// Software is furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be

// included in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

// OTHER DEALINGS IN THE SOFTWARE.

//----------------------------------------------------------------------//

import GFArith::*;

import GFTypes::*;

import Vector::*;

import GetPut::*;

import FIFO::*;

// ---------------------------------------------------------

// Reed-Solomon error corrector interface

// ---------------------------------------------------------

interface IErrorCorrector;

   method Action              r_in (Byte datum);

   method Action              e_in (Byte datum);

   method Action              k_in (Byte k_new);

   method Action              no_error_flag_in (Bool no_error);

   method ActionValue#(Byte)  d_out ();

endinterface

// ---------------------------------------------------------

// Reed-Solomon error corrector module

// ---------------------------------------------------------

(* synthesize *)

module mkErrorCorrector (IErrorCorrector);

   FIFO#(Byte)      r              <- mkSizedFIFO(2);

   FIFO#(Byte)      e              <- mkSizedFIFO(2);

   FIFO#(Byte)      d              <- mkSizedFIFO(2);

   FIFO#(Byte)      k              <- mkSizedFIFO(1);

   FIFO#(Bool)      no_error_flag  <- mkSizedFIFO(1);

   Reg#(Byte)       e_cnt          <- mkReg(0);

   Reg#(Byte)       block_number   <- mkReg(0);

   rule d_no_error (e_cnt < k.first() && no_error_flag.first());

      $display ("  [error corrector %d] No Error processing", block_number);

      r.deq();

      d.enq(r.first());

      if (e_cnt == k.first()-1)

         begin

            block_number <= block_number + 1;

            k.deq();

            no_error_flag.deq();

            e_cnt <= 0;

         end

      else

         e_cnt <= e_cnt + 1;

   endrule

   rule d_corrected (e_cnt < k.first() && !no_error_flag.first());

      $display ("  [error corrector %d]  Correction processing", block_number);

      r.deq();

      e.deq();

      d.enq(r.first() ^ e.first());

      if (e_cnt == k.first()-1)

         begin

            block_number <= block_number + 1;

            k.deq();

            no_error_flag.deq();

            e_cnt <= 0;

         end

      else

         e_cnt <= e_cnt + 1;

   endrule

   // ------------------------------------------------

   method Action r_in (Byte datum);

      $display ("  [error corrector %d]  r_in : %d)", block_number, datum);

      r.enq(datum);

   endmethod

   // ------------------------------------------------

   method Action e_in (Byte datum);

      e.enq(datum);

      $display ("  [error corrector %d]  Valid e_in : %d)", block_number, datum);

   endmethod

   // ------------------------------------------------

   method Action k_in (Byte k_new);

      $display ("  [error corrector %d]  k_in : %d", block_number, k_new);

      k.enq(k_new);

   endmethod

   // ------------------------------------------------

   method Action no_error_flag_in (Bool no_error);

      $display ("  [error corrector %d]  no_error : %d", block_number, no_error);

      no_error_flag.enq(no_error);

   endmethod

   // ------------------------------------------------

   method ActionValue#(Byte) d_out ();

      $display ("  [error corrector %d]  d_out (%d)", block_number, d.first());

      d.deq();

      return d.first();

   endmethod

endmodule