Subversion Repositories bluespec-reedsolomon

//----------------------------------------------------------------------//
// The MIT License 
// 
// Copyright (c) 2008 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;
}