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.

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

#include "global_rs.h"

#include "gf_arith.h"

#include "chien_search.h"

// Directive: Synthesize independently

void chien_search(  unsigned char k, unsigned char t, unsigned char lambda[tt],

                    unsigned char *err_no, unsigned char err_loc[tt], unsigned char alpha_inv[tt])

{

    unsigned char accum = 0;

    unsigned char err_cnt = 0;

    unsigned char alphainv = 1;

    unsigned char lambda_a[tt];

    unsigned char err_loc_temp[tt];

    unsigned char alpha_inv_temp[tt];

    // Directive: Unroll loop maximally

    Chien_AssignInArray: for (int i = 0; i < tt; i++)

       lambda_a[i] = lambda[i];

    for (int i = nn-1; i >= 0; i--)

    {

       // Directive: Unroll loop maximally

       Chien_Inner1: for (int j = 0; j < tt; j++)

            lambda_a[j] = gfmult_hw(lambda_a[j], alpha(j+1));

       accum = 1;

       // Directive: Unroll loop maximally   

       Chien_Inner2: for (int j = 0; j < tt; j++)

            accum = gfadd_hw(accum, lambda_a[j]);

       alphainv = gfmult_hw(alphainv, 2);

       if ((i >= 2*tt) && (i < kk+2*tt) && (accum == 0))

       {

            err_loc_temp[err_cnt] = i-2*tt;

            alpha_inv_temp[err_cnt] = alphainv;

            err_cnt++ ;

       }

    }

    // Directive: Unroll loop maximally

    Chien_AssignOutArray: for (int i = 0; i < tt; i++)

    {

       err_loc[i]   = err_loc_temp[i];

       alpha_inv[i] = alpha_inv_temp[i];

    }

    *err_no = err_cnt;

}