| /* |
| * Copyright (c) 2019 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. |
| * |
| * Authors: Daniel Carvalho |
| */ |
| |
| /** @file |
| * Implementation of the FPC-D cache compressor. |
| */ |
| |
| #include "mem/cache/compressors/fpcd.hh" |
| |
| #include "mem/cache/compressors/dictionary_compressor_impl.hh" |
| #include "params/FPCD.hh" |
| |
| FPCD::FPCD(const Params *p) |
| : DictionaryCompressor<uint32_t>(p) |
| { |
| } |
| |
| void |
| FPCD::addToDictionary(DictionaryEntry data) |
| { |
| // The dictionary behaves as a table with FIFO as replacement policy |
| if (numEntries == 2) { |
| dictionary[penultimateIndex] = dictionary[previousIndex]; |
| dictionary[previousIndex] = data; |
| } else { |
| dictionary[numEntries++] = data; |
| } |
| } |
| |
| std::unique_ptr<BaseCacheCompressor::CompressionData> |
| FPCD::compress(const uint64_t* data, Cycles& comp_lat, Cycles& decomp_lat) |
| { |
| std::unique_ptr<BaseCacheCompressor::CompressionData> comp_data = |
| DictionaryCompressor<uint32_t>::compress(data); |
| |
| // Set compression latency (Accounts for zero checks, ones check, match |
| // previous check, match penultimate check, repeated values check, pattern |
| // selection, shifting, at a rate of 16B per cycle) |
| comp_lat = Cycles(blkSize/2); |
| |
| // Set decompression latency. The original claim of 2 cycles is likely |
| // too unrealistic |
| decomp_lat = Cycles(4); |
| |
| // Return compressed line |
| return comp_data; |
| } |
| |
| FPCD* |
| FPCDParams::create() |
| { |
| return new FPCD(this); |
| } |