| /* |
| * Copyright (c) 2003-2005 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: Erik Hallnor |
| */ |
| |
| /** |
| * @file |
| * Declaration of a LRU tag store. |
| */ |
| |
| #ifndef __MEM_CACHE_TAGS_LRU_HH__ |
| #define __MEM_CACHE_TAGS_LRU_HH__ |
| |
| #include <cassert> |
| #include <cstring> |
| #include <list> |
| |
| #include "mem/cache/blk.hh" |
| #include "mem/cache/tags/base.hh" |
| #include "mem/packet.hh" |
| |
| class BaseCache; |
| |
| /** |
| * LRU cache block. |
| */ |
| class LRUBlk : public CacheBlk { |
| public: |
| /** Has this block been touched? Used to aid calculation of warmup time. */ |
| bool isTouched; |
| }; |
| |
| /** |
| * An associative set of cache blocks. |
| */ |
| class CacheSet |
| { |
| public: |
| /** The associativity of this set. */ |
| int assoc; |
| |
| /** Cache blocks in this set, maintained in LRU order 0 = MRU. */ |
| LRUBlk **blks; |
| |
| /** |
| * Find a block matching the tag in this set. |
| * @param asid The address space ID. |
| * @param tag The Tag to find. |
| * @return Pointer to the block if found. |
| */ |
| LRUBlk* findBlk(Addr tag) const; |
| |
| /** |
| * Move the given block to the head of the list. |
| * @param blk The block to move. |
| */ |
| void moveToHead(LRUBlk *blk); |
| }; |
| |
| /** |
| * A LRU cache tag store. |
| */ |
| class LRU : public BaseTags |
| { |
| public: |
| /** Typedef the block type used in this tag store. */ |
| typedef LRUBlk BlkType; |
| /** Typedef for a list of pointers to the local block class. */ |
| typedef std::list<LRUBlk*> BlkList; |
| |
| protected: |
| /** The number of sets in the cache. */ |
| const unsigned numSets; |
| /** The number of bytes in a block. */ |
| const unsigned blkSize; |
| /** The associativity of the cache. */ |
| const unsigned assoc; |
| /** The hit latency. */ |
| const unsigned hitLatency; |
| |
| /** The cache sets. */ |
| CacheSet *sets; |
| |
| /** The cache blocks. */ |
| LRUBlk *blks; |
| /** The data blocks, 1 per cache block. */ |
| uint8_t *dataBlks; |
| |
| /** The amount to shift the address to get the set. */ |
| int setShift; |
| /** The amount to shift the address to get the tag. */ |
| int tagShift; |
| /** Mask out all bits that aren't part of the set index. */ |
| unsigned setMask; |
| /** Mask out all bits that aren't part of the block offset. */ |
| unsigned blkMask; |
| |
| public: |
| /** |
| * Construct and initialize this tag store. |
| * @param _numSets The number of sets in the cache. |
| * @param _blkSize The number of bytes in a block. |
| * @param _assoc The associativity of the cache. |
| * @param _hit_latency The latency in cycles for a hit. |
| */ |
| LRU(unsigned _numSets, unsigned _blkSize, unsigned _assoc, |
| unsigned _hit_latency); |
| |
| /** |
| * Destructor |
| */ |
| virtual ~LRU(); |
| |
| /** |
| * Return the block size. |
| * @return the block size. |
| */ |
| unsigned |
| getBlockSize() const |
| { |
| return blkSize; |
| } |
| |
| /** |
| * Return the subblock size. In the case of LRU it is always the block |
| * size. |
| * @return The block size. |
| */ |
| unsigned |
| getSubBlockSize() const |
| { |
| return blkSize; |
| } |
| |
| /** |
| * Invalidate the given block. |
| * @param blk The block to invalidate. |
| */ |
| void invalidateBlk(BlkType *blk); |
| |
| /** |
| * Access block and update replacement data. May not succeed, in which case |
| * NULL pointer is returned. This has all the implications of a cache |
| * access and should only be used as such. Returns the access latency as a side effect. |
| * @param addr The address to find. |
| * @param asid The address space ID. |
| * @param lat The access latency. |
| * @return Pointer to the cache block if found. |
| */ |
| LRUBlk* accessBlock(Addr addr, int &lat); |
| |
| /** |
| * Finds the given address in the cache, do not update replacement data. |
| * i.e. This is a no-side-effect find of a block. |
| * @param addr The address to find. |
| * @param asid The address space ID. |
| * @return Pointer to the cache block if found. |
| */ |
| LRUBlk* findBlock(Addr addr) const; |
| |
| /** |
| * Find a block to evict for the address provided. |
| * @param addr The addr to a find a replacement candidate for. |
| * @param writebacks List for any writebacks to be performed. |
| * @return The candidate block. |
| */ |
| LRUBlk* findVictim(Addr addr, PacketList &writebacks); |
| |
| /** |
| * Insert the new block into the cache. For LRU this means inserting into |
| * the MRU position of the set. |
| * @param addr The address to update. |
| * @param blk The block to update. |
| */ |
| void insertBlock(Addr addr, BlkType *blk); |
| |
| /** |
| * Generate the tag from the given address. |
| * @param addr The address to get the tag from. |
| * @return The tag of the address. |
| */ |
| Addr extractTag(Addr addr) const |
| { |
| return (addr >> tagShift); |
| } |
| |
| /** |
| * Calculate the set index from the address. |
| * @param addr The address to get the set from. |
| * @return The set index of the address. |
| */ |
| int extractSet(Addr addr) const |
| { |
| return ((addr >> setShift) & setMask); |
| } |
| |
| /** |
| * Get the block offset from an address. |
| * @param addr The address to get the offset of. |
| * @return The block offset. |
| */ |
| int extractBlkOffset(Addr addr) const |
| { |
| return (addr & blkMask); |
| } |
| |
| /** |
| * Align an address to the block size. |
| * @param addr the address to align. |
| * @return The block address. |
| */ |
| Addr blkAlign(Addr addr) const |
| { |
| return (addr & ~(Addr)blkMask); |
| } |
| |
| /** |
| * Regenerate the block address from the tag. |
| * @param tag The tag of the block. |
| * @param set The set of the block. |
| * @return The block address. |
| */ |
| Addr regenerateBlkAddr(Addr tag, unsigned set) const |
| { |
| return ((tag << tagShift) | ((Addr)set << setShift)); |
| } |
| |
| /** |
| * Return the hit latency. |
| * @return the hit latency. |
| */ |
| int getHitLatency() const |
| { |
| return hitLatency; |
| } |
| |
| /** |
| * Called at end of simulation to complete average block reference stats. |
| */ |
| virtual void cleanupRefs(); |
| }; |
| |
| #endif // __MEM_CACHE_TAGS_LRU_HH__ |