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Diffstat (limited to 'src/mem/cache/tags/lru.hh')
-rw-r--r-- | src/mem/cache/tags/lru.hh | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/src/mem/cache/tags/lru.hh b/src/mem/cache/tags/lru.hh new file mode 100644 index 000000000..437244660 --- /dev/null +++ b/src/mem/cache/tags/lru.hh @@ -0,0 +1,327 @@ +/* + * 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 __LRU_HH__ +#define __LRU_HH__ + +#include <list> + +#include "mem/cache/cache_blk.hh" // base class +#include "mem/packet.hh" // for inlined functions +#include <assert.h> +#include "mem/cache/tags/base_tags.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(int asid, 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 int numSets; + /** The number of bytes in a block. */ + const int blkSize; + /** The associativity of the cache. */ + const int assoc; + /** The hit latency. */ + const int 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(int _numSets, int _blkSize, int _assoc, int _hit_latency); + + /** + * Destructor + */ + virtual ~LRU(); + + /** + * Return the block size. + * @return the block size. + */ + int getBlockSize() + { + return blkSize; + } + + /** + * Return the subblock size. In the case of LRU it is always the block + * size. + * @return The block size. + */ + int getSubBlockSize() + { + return blkSize; + } + + /** + * Search for the address in the cache. + * @param asid The address space ID. + * @param addr The address to find. + * @return True if the address is in the cache. + */ + bool probe(int asid, Addr addr) const; + + /** + * Invalidate the block containing the given address. + * @param asid The address space ID. + * @param addr The address to invalidate. + */ + void invalidateBlk(int asid, Addr addr); + + /** + * Finds the given address in the cache and update replacement data. + * Returns the access latency as a side effect. + * @param req The request whose block to find. + * @param lat The access latency. + * @return Pointer to the cache block if found. + */ + LRUBlk* findBlock(Packet * &pkt, int &lat); + + /** + * Finds the given address in the cache and update replacement data. + * 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* findBlock(Addr addr, int asid, int &lat); + + /** + * Finds the given address in the cache, do not update replacement data. + * @param addr The address to find. + * @param asid The address space ID. + * @return Pointer to the cache block if found. + */ + LRUBlk* findBlock(Addr addr, int asid) const; + + /** + * Find a replacement block for the address provided. + * @param req The request to a find a replacement candidate for. + * @param writebacks List for any writebacks to be performed. + * @param compress_blocks List of blocks to compress, for adaptive comp. + * @return The block to place the replacement in. + */ + LRUBlk* findReplacement(Packet * &pkt, PacketList &writebacks, + BlkList &compress_blocks); + + /** + * 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); + } + + /** + * Generate the tag from the given address. + * @param addr The address to get the tag from. + * @param blk Ignored. + * @return The tag of the address. + */ + Addr extractTag(Addr addr, LRUBlk *blk) 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; + } + + /** + * Read the data out of the internal storage of the given cache block. + * @param blk The cache block to read. + * @param data The buffer to read the data into. + * @return The cache block's data. + */ + void readData(LRUBlk *blk, uint8_t *data) + { + memcpy(data, blk->data, blk->size); + } + + /** + * Write data into the internal storage of the given cache block. Since in + * LRU does not store data differently this just needs to update the size. + * @param blk The cache block to write. + * @param data The data to write. + * @param size The number of bytes to write. + * @param writebacks A list for any writebacks to be performed. May be + * needed when writing to a compressed block. + */ + void writeData(LRUBlk *blk, uint8_t *data, int size, + PacketList & writebacks) + { + assert(size <= blkSize); + blk->size = size; + } + + /** + * Perform a block aligned copy from the source address to the destination. + * @param source The block-aligned source address. + * @param dest The block-aligned destination address. + * @param asid The address space DI. + * @param writebacks List for any generated writeback requests. + */ + void doCopy(Addr source, Addr dest, int asid, PacketList &writebacks); + + /** + * No impl. + */ + void fixCopy(Packet * &pkt, PacketList &writebacks) + { + } + + /** + * Called at end of simulation to complete average block reference stats. + */ + virtual void cleanupRefs(); +}; + +#endif |