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/*
* Copyright (c) 2013 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2009 The Regents of The University of Michigan
* 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.
*
* Authors: Lisa Hsu
*/
/**
* @file
* Declaration of an associative set
*/
#ifndef __MEM_CACHE_TAGS_CACHESET_HH__
#define __MEM_CACHE_TAGS_CACHESET_HH__
#include <cassert>
#include <vector>
#include "base/types.hh"
/**
* An associative set of cache blocks.
*/
template <class Blktype>
class CacheSet
{
public:
/** The associativity of this set. */
int assoc;
/** Cache blocks in this set, maintained in LRU order 0 = MRU. */
std::vector<Blktype*> blks;
/**
* Find a block matching the tag in this set.
* @param way_id The id of the way that matches the tag.
* @param tag The Tag to find.
* @param is_secure True if the target memory space is secure.
* @return Pointer to the block if found. Set way_id to assoc if none found
*/
Blktype* findBlk(Addr tag, bool is_secure, int& way_id) const ;
Blktype* findBlk(Addr tag, bool is_secure) const ;
/**
* Move the given block to the head of the list.
* @param blk The block to move.
*/
void moveToHead(Blktype *blk);
/**
* Move the given block to the tail of the list.
* @param blk The block to move
*/
void moveToTail(Blktype *blk);
};
template <class Blktype>
Blktype*
CacheSet<Blktype>::findBlk(Addr tag, bool is_secure, int& way_id) const
{
/**
* Way_id returns the id of the way that matches the block
* If no block is found way_id is set to assoc.
*/
way_id = assoc;
for (int i = 0; i < assoc; ++i) {
if (blks[i]->tag == tag && blks[i]->isValid() &&
blks[i]->isSecure() == is_secure) {
way_id = i;
return blks[i];
}
}
return nullptr;
}
template <class Blktype>
Blktype*
CacheSet<Blktype>::findBlk(Addr tag, bool is_secure) const
{
int ignored_way_id;
return findBlk(tag, is_secure, ignored_way_id);
}
template <class Blktype>
void
CacheSet<Blktype>::moveToHead(Blktype *blk)
{
// nothing to do if blk is already head
if (blks[0] == blk)
return;
// write 'next' block into blks[i], moving up from MRU toward LRU
// until we overwrite the block we moved to head.
// start by setting up to write 'blk' into blks[0]
int i = 0;
Blktype *next = blk;
do {
assert(i < assoc);
std::swap(blks[i], next);
++i;
} while (next != blk);
}
template <class Blktype>
void
CacheSet<Blktype>::moveToTail(Blktype *blk)
{
// nothing to do if blk is already tail
if (blks[assoc - 1] == blk)
return;
// write 'next' block into blks[i], moving from LRU to MRU
// until we overwrite the block we moved to tail.
// start by setting up to write 'blk' into tail
int i = assoc - 1;
Blktype *next = blk;
do {
assert(i >= 0);
std::swap(blks[i], next);
--i;
} while (next != blk);
}
#endif
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