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/*
* Copyright (c) 2019-2020 Inria
* 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.
*/
/** @file
* Implementation of a perfect compressor, which compresses data to its
* maximum allowed compression ratio.
*/
#include "mem/cache/compressors/perfect.hh"
#include <algorithm>
#include "debug/CacheComp.hh"
#include "params/PerfectCompressor.hh"
namespace Compressor {
Perfect::Perfect(const Params &p)
: Base(p), compressedSize(8 * blkSize / p.max_compression_ratio)
{
}
std::unique_ptr<Base::CompressionData>
Perfect::compress(const std::vector<Chunk>& chunks,
Cycles& comp_lat, Cycles& decomp_lat)
{
// Compress every word sequentially
std::unique_ptr<Base::CompressionData> comp_data(new CompData(chunks));
// Set relevant metadata
comp_data->setSizeBits(compressedSize);
// Set latencies based on the degree of parallelization, and any extra
// latencies due to shifting or packaging
comp_lat = Cycles((chunks.size() / compChunksPerCycle) + compExtraLatency);
decomp_lat = Cycles((chunks.size() / decompChunksPerCycle) +
decompExtraLatency);
return comp_data;
}
void
Perfect::decompress(const CompressionData* comp_data,
uint64_t* data)
{
// Decompress every entry sequentially
fromChunks(static_cast<const CompData*>(comp_data)->chunks, data);
}
} // namespace Compressor