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28 * Authors: Daniel Carvalho
32 * Implementation of the FPC-D cache compressor.
35 #include "mem/cache/compressors/fpcd.hh"
37 #include "mem/cache/compressors/dictionary_compressor_impl.hh"
38 #include "params/FPCD.hh"
40 FPCD::FPCD(const Params
*p
)
41 : DictionaryCompressor
<uint32_t>(p
)
46 FPCD::addToDictionary(DictionaryEntry data
)
48 // The dictionary behaves as a table with FIFO as replacement policy
49 if (numEntries
== 2) {
50 dictionary
[penultimateIndex
] = dictionary
[previousIndex
];
51 dictionary
[previousIndex
] = data
;
53 dictionary
[numEntries
++] = data
;
57 std::unique_ptr
<BaseCacheCompressor::CompressionData
>
58 FPCD::compress(const uint64_t* data
, Cycles
& comp_lat
, Cycles
& decomp_lat
)
60 std::unique_ptr
<BaseCacheCompressor::CompressionData
> comp_data
=
61 DictionaryCompressor
<uint32_t>::compress(data
);
63 // Set compression latency (Accounts for zero checks, ones check, match
64 // previous check, match penultimate check, repeated values check, pattern
65 // selection, shifting, at a rate of 16B per cycle)
66 comp_lat
= Cycles(blkSize
/2);
68 // Set decompression latency. The original claim of 2 cycles is likely
70 decomp_lat
= Cycles(4);
72 // Return compressed line
79 return new FPCD(this);