Initial commit of OpenSPARC T2 architecture model.

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

/*
* ========== Copyright Header Begin ==========================================
* 
* OpenSPARC T2 Processor File: BL_BaseEcc.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 **  Sun considers its source code as an unpublished, proprietary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_BaseEcc_h__
#define __BL_BaseEcc_h__
#include <assert.h>
#include "BL_BitUtility.h"

class BL_EccBits
{
  public:

    BL_EccBits() : check_bits(0), is_valid(0) {}

    BL_EccBits(unsigned short _check_bits) : check_bits(_check_bits), is_valid(true) {}

    virtual ~BL_EccBits() {}

    unsigned short get() const
    {
      assert(is_valid); return check_bits;
    }

    BL_EccBits& set(unsigned short _check_bits)
    {
      is_valid = true; check_bits = _check_bits;
      return *this;
    }

    bool valid() const { return is_valid; }

    BL_EccBits& valid(bool v) { is_valid = v; return *this; }

  private:
    unsigned short        is_valid:1;
    unsigned short        check_bits:15;
};

// This method calculates the ecc check bits for a given data item and 
// requires three parameters
// The first parameter specifies the number of ECC check bits
// The second parameter provide the masks that are required to identify 
// which data bits are associated with a given check bit
// Masks are provided with the "most significant check bits first"
// The third parameter is the data 
template <typename DataType>
BL_EccBits calc_checks(unsigned n_patterns,
                              DataType *patterns, DataType data)
{
  unsigned i;
  unsigned parity;
  unsigned checks = 0;

  // for each check bit
  for (i = 0; i < n_patterns; i++) 
  {
    // Calculate check bit value
    parity = BL_BitUtility::calc_parity( data & *patterns++ );  
    // Accumulate check bits
    checks <<= 1;                                
    checks |= parity;
  }
  //return checks;
  return BL_EccBits(checks);
}    

#endif