Initial commit of OpenSPARC T2 architecture model.

[OpenSPARC-T2-SAM] / sam-t2 / sam / cpus / vonk / bl / lib / ecc / src / BL_Hsiao_256_10_Synd.h

/*
* ========== Copyright Header Begin ==========================================
* 
* OpenSPARC T2 Processor File: BL_Hsiao_256_10_Synd.h
* Copyright (c) 2006 Sun Microsystems, Inc.  All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES.
* 
* The above named program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License version 2 as published by the Free Software Foundation.
* 
* The above named program 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
* General Public License for more details.
* 
* You should have received a copy of the GNU General Public
* License along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
* 
* ========== Copyright Header End ============================================
*/
/************************************************************************
**  
**  Copyright (C) 2006, Sun Microsystems, Inc.
**
**  Sun considers its source code as an unpublished, proprietary
**  trade secret and it is available only under strict license provisions.
**  This copyright notice is placed here only to protect Sun in the event 
**  the source is deemed a published work. Disassembly, decompilation,
**  or other means of reducing the object code to human readable form
**  is prohibited by the license agreement under which this code is
**  provided to the user or company in possession of this copy.
**
*************************************************************************/
#ifndef __BL_Hsiao_256_10_Synd_h__
#define __BL_Hsiao_256_10_Synd_h__
#include "BL_Utils.h"
#include "BL_BaseSynd.h"
#include "BL_HsiaoEcc.h"

class BL_Hsiao_256_10_Synd : public BL_BaseSynd
{
 public:       

   BL_Hsiao_256_10_Synd(uint32_t syndrome) : BL_BaseSynd(syndrome)
   {
     if (syndrome > 0x3ff)
     {
       fprintf(stderr,"ERROR: Bad Syndrome: 0x%x", syndrome);
       exit(-1);             
     }
   }

   BL_Hsiao_256_10_Synd(BL_Uint256 data, BL_EccBits ecc) :
     BL_BaseSynd(BL_Hsiao_256_10_Synd::calc_check_bits(data).get() ^ ecc.get())
   {}


   ~BL_Hsiao_256_10_Synd() {}

   bool isDoubleBitError() const 
   {
     return (syndrome_ != 0) && !isSingleBitError();
   }

   bool isSingleBitError() const
   {
     if (syndrome_ == 0)
       return false;
     switch (nr_bits_set())
     {
     case 1:
     case 3:
       return true;
     case 5:
       return find_syndrome_ndx() != -1;
     default:
       return false;
     }
   }

   bool isDataBitError() const 
   {
     return (isSingleBitError() && nr_bits_set() > 1);
   }

   // This method works because the check bits are at powers of 2
   // (after substracting 0x80) so the data bits break up into
   // large ranges.
   uint32_t getDataBit() const 
   {
     if (!isDataBitError())
     {
       fprintf(stderr,"ERROR: Not data bit error!");
       exit(-1);             
     }       
       
     return find_syndrome_ndx();
   }
   
   bool isCheckBitError() const 
   {
     return (isSingleBitError() && is_power_of_two(syndrome_));
   }

   uint32_t getCheckBit() const 
   {
     if (!isCheckBitError())
     {
       fprintf(stderr,"ERROR: Not check bit error!");
       exit(-1);             
     }       
     return bit2idx(syndrome_);        
   }

   bool isMultipleBitError() const { return false; }

   static BL_EccBits calc_check_bits(BL_Uint256 data)
   {
     BL_Uint256 *patterns =
       BL_Hsiao_256_10_Synd::hsiao_256_10_patterns.patterns;
     return calc_checks(10, patterns, data);

   }

 private:

   BL_Hsiao_256_10_Synd();    

   // Number of bits set in syndrome
   // This trick works up to 12 bits
   uint_t nr_bits_set() const
   {
     return (syndrome_ * 0x1001001001001ULL & 0x84210842108421ULL) % 0x1f;
   }

   int find_syndrome_ndx() const
   {
     switch (nr_bits_set())
     {
     case 3:
       for (uint_t ndx = 0; ndx < 120; ++ndx)
         if (syndrome_ == hsiao_256_10_patterns.get(ndx).get())
           return ndx;
       assert(0);
       break;
     case 5:
       for (uint_t ndx = 120; ndx < 256; ++ndx)
         if (syndrome_ == hsiao_256_10_patterns.get(ndx).get())
           return ndx;
     default:
       break;
     }
     return -1;                // -1 is didn't find it
   }

  class Patterns
   {
     public:
       BL_Uint256         patterns[10];

       Patterns();

       ~Patterns() {}

       BL_EccBits get(uint_t ndx) const { return syndromes[ndx]; }

     private:

       static uint64_t calc_pattern(uint_t syndrome_ndx, uint_t pattern_ndx);

       static BL_EccBits syndromes[256];
   };

   static Patterns     hsiao_256_10_patterns;

};

#endif