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Diffstat (limited to 'src/mem/cache/cache_blk.hh')
| -rw-r--r-- | src/mem/cache/cache_blk.hh | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/src/mem/cache/cache_blk.hh b/src/mem/cache/cache_blk.hh new file mode 100644 index 000000000..cf1bd20e2 --- /dev/null +++ b/src/mem/cache/cache_blk.hh @@ -0,0 +1,203 @@ +/* + * 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 + * Definitions of a simple cache block class. + */ + +#ifndef __CACHE_BLK_HH__ +#define __CACHE_BLK_HH__ + +#include "sim/root.hh" // for Tick +#include "arch/isa_traits.hh" // for Addr +#include "cpu/exec_context.hh" + +/** + * Cache block status bit assignments + */ +enum CacheBlkStatusBits { + /** valid, readable */ + BlkValid = 0x01, + /** write permission */ + BlkWritable = 0x02, + /** dirty (modified) */ + BlkDirty = 0x04, + /** compressed */ + BlkCompressed = 0x08, + /** block was referenced */ + BlkReferenced = 0x10, + /** block was a hardware prefetch yet unaccessed*/ + BlkHWPrefetched = 0x20 +}; + +/** + * A Basic Cache block. + * Contains the tag, status, and a pointer to data. + */ +class CacheBlk +{ + public: + /** The address space ID of this block. */ + int asid; + /** Data block tag value. */ + Addr tag; + /** + * Contains a copy of the data in this block for easy access. This is used + * for efficient execution when the data could be actually stored in + * another format (COW, compressed, sub-blocked, etc). In all cases the + * data stored here should be kept consistant with the actual data + * referenced by this block. + */ + uint8_t *data; + /** the number of bytes stored in this block. */ + int size; + + /** block state: OR of CacheBlkStatusBit */ + typedef unsigned State; + + /** The current status of this block. @sa CacheBlockStatusBits */ + State status; + + /** Which curTick will this block be accessable */ + Tick whenReady; + + /** Save the exec context so that writebacks can use them. */ + ExecContext *xc; + + /** + * The set this block belongs to. + * @todo Move this into subclasses when we fix CacheTags to use them. + */ + int set; + + /** Number of references to this block since it was brought in. */ + int refCount; + + CacheBlk() + : asid(-1), tag(0), data(0) ,size(0), status(0), whenReady(0), xc(0), + set(-1), refCount(0) + {} + + /** + * Copy the state of the given block into this one. + * @param rhs The block to copy. + * @return a const reference to this block. + */ + const CacheBlk& operator=(const CacheBlk& rhs) + { + asid = rhs.asid; + tag = rhs.tag; + data = rhs.data; + size = rhs.size; + status = rhs.status; + whenReady = rhs.whenReady; + xc = rhs.xc; + set = rhs.set; + refCount = rhs.refCount; + return *this; + } + + /** + * Checks the write permissions of this block. + * @return True if the block is writable. + */ + bool isWritable() const + { + const int needed_bits = BlkWritable | BlkValid; + return (status & needed_bits) == needed_bits; + } + + /** + * Checks that a block is valid (readable). + * @return True if the block is valid. + */ + bool isValid() const + { + return (status & BlkValid) != 0; + } + + /** + * Check to see if a block has been written. + * @return True if the block is dirty. + */ + bool isModified() const + { + return (status & BlkDirty) != 0; + } + + /** + * Check to see if this block contains compressed data. + * @return True iF the block's data is compressed. + */ + bool isCompressed() const + { + return (status & BlkCompressed) != 0; + } + + /** + * Check if this block has been referenced. + * @return True if the block has been referenced. + */ + bool isReferenced() const + { + return (status & BlkReferenced) != 0; + } + + /** + * Check if this block was the result of a hardware prefetch, yet to + * be touched. + * @return True if the block was a hardware prefetch, unaccesed. + */ + bool isPrefetch() const + { + return (status & BlkHWPrefetched) != 0; + } + + +}; + +/** + * Output a CacheBlk to the given ostream. + * @param out The stream for the output. + * @param blk The cache block to print. + * + * @return The output stream. + */ +inline std::ostream & +operator<<(std::ostream &out, const CacheBlk &blk) +{ + out << std::hex << std::endl; + out << " Tag: " << blk.tag << std::endl; + out << " Status: " << blk.status << std::endl; + + return(out << std::dec); +} + +#endif //__CACHE_BLK_HH__ |