gem5/src/mem/ruby/system/PerfectCacheMemory.hh

/*
 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * PerfectCacheMemory.hh
 *
 * Description:
 *
 * $Id$
 *
 */

#ifndef PERFECTCACHEMEMORY_H
#define PERFECTCACHEMEMORY_H

#include "mem/ruby/common/Global.hh"
#include "mem/gems_common/Map.hh"
#include "mem/protocol/AccessPermission.hh"
#include "mem/ruby/common/Address.hh"

template<class ENTRY>
class PerfectCacheLineState {
public:
  PerfectCacheLineState() { m_permission = AccessPermission_NUM; }
  AccessPermission m_permission;
  ENTRY m_entry;
};

template<class ENTRY>
extern inline
ostream& operator<<(ostream& out, const PerfectCacheLineState<ENTRY>& obj)
{
  return out;
}

template<class ENTRY>
class PerfectCacheMemory {
public:

  // Constructors
  PerfectCacheMemory();

  // Destructor
  //~PerfectCacheMemory();

  // Public Methods

  static void printConfig(ostream& out);

  // perform a cache access and see if we hit or not.  Return true on
  // a hit.
  bool tryCacheAccess(const CacheMsg& msg, bool& block_stc, ENTRY*& entry);

  // tests to see if an address is present in the cache
  bool isTagPresent(const Address& address) const;

  // Returns true if there is:
  //   a) a tag match on this address or there is
  //   b) an Invalid line in the same cache "way"
  bool cacheAvail(const Address& address) const;

  // find an Invalid entry and sets the tag appropriate for the address
  void allocate(const Address& address);

  void deallocate(const Address& address);

  // Returns with the physical address of the conflicting cache line
  Address cacheProbe(const Address& newAddress) const;

  // looks an address up in the cache
  ENTRY& lookup(const Address& address);
  const ENTRY& lookup(const Address& address) const;

  // Get/Set permission of cache block
  AccessPermission getPermission(const Address& address) const;
  void changePermission(const Address& address, AccessPermission new_perm);

  // Print cache contents
  void print(ostream& out) const;
private:
  // Private Methods

  // Private copy constructor and assignment operator
  PerfectCacheMemory(const PerfectCacheMemory& obj);
  PerfectCacheMemory& operator=(const PerfectCacheMemory& obj);

  // Data Members (m_prefix)
  Map<Address, PerfectCacheLineState<ENTRY> > m_map;
};

// Output operator declaration
//ostream& operator<<(ostream& out, const PerfectCacheMemory<ENTRY>& obj);

// ******************* Definitions *******************

// Output operator definition
template<class ENTRY>
extern inline
ostream& operator<<(ostream& out, const PerfectCacheMemory<ENTRY>& obj)
{
  obj.print(out);
  out << flush;
  return out;
}


// ****************************************************************

template<class ENTRY>
extern inline
PerfectCacheMemory<ENTRY>::PerfectCacheMemory()
{
}

// STATIC METHODS

template<class ENTRY>
extern inline
void PerfectCacheMemory<ENTRY>::printConfig(ostream& out)
{
}

// PUBLIC METHODS

template<class ENTRY>
extern inline
bool PerfectCacheMemory<ENTRY>::tryCacheAccess(const CacheMsg& msg, bool& block_stc, ENTRY*& entry)
{
  ERROR_MSG("not implemented");
}

// tests to see if an address is present in the cache
template<class ENTRY>
extern inline
bool PerfectCacheMemory<ENTRY>::isTagPresent(const Address& address) const
{
  return m_map.exist(line_address(address));
}

template<class ENTRY>
extern inline
bool PerfectCacheMemory<ENTRY>::cacheAvail(const Address& address) const
{
  return true;
}

// find an Invalid or already allocated entry and sets the tag
// appropriate for the address
template<class ENTRY>
extern inline
void PerfectCacheMemory<ENTRY>::allocate(const Address& address)
{
  PerfectCacheLineState<ENTRY> line_state;
  line_state.m_permission = AccessPermission_Busy;
  line_state.m_entry = ENTRY();
  m_map.add(line_address(address), line_state);
}

// deallocate entry
template<class ENTRY>
extern inline
void PerfectCacheMemory<ENTRY>::deallocate(const Address& address)
{
  m_map.erase(line_address(address));
}

// Returns with the physical address of the conflicting cache line
template<class ENTRY>
extern inline
Address PerfectCacheMemory<ENTRY>::cacheProbe(const Address& newAddress) const
{
  ERROR_MSG("cacheProbe called in perfect cache");
}

// looks an address up in the cache
template<class ENTRY>
extern inline
ENTRY& PerfectCacheMemory<ENTRY>::lookup(const Address& address)
{
  return m_map.lookup(line_address(address)).m_entry;
}

// looks an address up in the cache
template<class ENTRY>
extern inline
const ENTRY& PerfectCacheMemory<ENTRY>::lookup(const Address& address) const
{
  return m_map.lookup(line_address(address)).m_entry;
}

template<class ENTRY>
extern inline
AccessPermission PerfectCacheMemory<ENTRY>::getPermission(const Address& address) const
{
  return m_map.lookup(line_address(address)).m_permission;
}

template<class ENTRY>
extern inline
void PerfectCacheMemory<ENTRY>::changePermission(const Address& address, AccessPermission new_perm)
{
  Address line_address = address;
  line_address.makeLineAddress();
  PerfectCacheLineState<ENTRY>& line_state = m_map.lookup(line_address);
  AccessPermission old_perm = line_state.m_permission;
  line_state.m_permission = new_perm;
}

template<class ENTRY>
extern inline
void PerfectCacheMemory<ENTRY>::print(ostream& out) const
{
}

#endif //PERFECTCACHEMEMORY_H