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**  Sun considers its source code as an unpublished, proprietary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