diff options
Diffstat (limited to 'src/mem')
| -rw-r--r-- | src/mem/cache/compressors/cpack.hh | 66 | ||||
| -rw-r--r-- | src/mem/cache/compressors/dictionary_compressor.hh | 66 |
2 files changed, 69 insertions, 63 deletions
diff --git a/src/mem/cache/compressors/cpack.hh b/src/mem/cache/compressors/cpack.hh index 3ecab5028..7b10ac3e7 100644 --- a/src/mem/cache/compressors/cpack.hh +++ b/src/mem/cache/compressors/cpack.hh @@ -154,55 +154,21 @@ class CPack::PatternXXXX : public UncompressedPattern } }; -class CPack::PatternMMMM : public DictionaryCompressor::Pattern +class CPack::PatternMMMM : public MaskedPattern<0xFFFFFFFF> { public: PatternMMMM(const DictionaryEntry bytes, const int match_location) - : Pattern(MMMM, 0x2, 6, 0, match_location, true) {} - - static bool isPattern(const DictionaryEntry& bytes, - const DictionaryEntry& dict_bytes, - const int match_location) - { - return (bytes == dict_bytes) && (match_location >= 0); - } - - DictionaryEntry - decompress(const DictionaryEntry dict_bytes) const override + : MaskedPattern<0xFFFFFFFF>(MMMM, 0x2, 6, match_location, bytes, true) { - return dict_bytes; } }; -class CPack::PatternMMXX : public DictionaryCompressor::Pattern +class CPack::PatternMMXX : public MaskedPattern<0xFFFF0000> { - private: - /** - * A copy of the unmatched bytes. - */ - const uint8_t byte0; - const uint8_t byte1; - public: PatternMMXX(const DictionaryEntry bytes, const int match_location) - : Pattern(MMXX, 0xC, 8, 2, match_location, true), - byte0(bytes[0]), byte1(bytes[1]) {} - - static bool isPattern(const DictionaryEntry& bytes, - const DictionaryEntry& dict_bytes, - const int match_location) - { - // Notice we don't compare bytes[0], as otherwise we'd be unnecessarily - // discarding MMXM. If that pattern is added this should be modified - return (bytes[3] == dict_bytes[3]) && (bytes[2] == dict_bytes[2]) && - (bytes[1] != dict_bytes[1]) && (match_location >= 0); - - } - - DictionaryEntry - decompress(const DictionaryEntry dict_bytes) const override + : MaskedPattern<0xFFFF0000>(MMXX, 0xC, 8, match_location, bytes, true) { - return {byte0, byte1, dict_bytes[2], dict_bytes[3]}; } }; @@ -233,32 +199,12 @@ class CPack::PatternZZZX : public DictionaryCompressor::Pattern } }; -class CPack::PatternMMMX : public DictionaryCompressor::Pattern +class CPack::PatternMMMX : public MaskedPattern<0xFFFFFF00> { - private: - /** - * A copy of the unmatched byte. - */ - const uint8_t byte; - public: PatternMMMX(const DictionaryEntry bytes, const int match_location) - : Pattern(MMMX, 0xE, 8, 1, match_location, true), - byte(bytes[0]) {} - - static bool isPattern(const DictionaryEntry& bytes, - const DictionaryEntry& dict_bytes, - const int match_location) - { - return (bytes[3] == dict_bytes[3]) && (bytes[2] == dict_bytes[2]) && - (bytes[1] == dict_bytes[1]) && (bytes[0] != dict_bytes[0]) && - (match_location >= 0); - } - - DictionaryEntry - decompress(const DictionaryEntry dict_bytes) const override + : MaskedPattern<0xFFFFFF00>(MMMX, 0xE, 8, match_location, bytes, true) { - return {byte, dict_bytes[1], dict_bytes[2], dict_bytes[3]}; } }; diff --git a/src/mem/cache/compressors/dictionary_compressor.hh b/src/mem/cache/compressors/dictionary_compressor.hh index 9e0e4df80..3c828f040 100644 --- a/src/mem/cache/compressors/dictionary_compressor.hh +++ b/src/mem/cache/compressors/dictionary_compressor.hh @@ -111,6 +111,9 @@ template <class T> class DictionaryCompressor : public BaseDictionaryCompressor { protected: + /** Convenience typedef for a dictionary entry. */ + typedef std::array<uint8_t, sizeof(T)> DictionaryEntry; + /** * Compression data for the dictionary compressor. It consists of a vector * of patterns. @@ -120,9 +123,8 @@ class DictionaryCompressor : public BaseDictionaryCompressor // Forward declaration of a pattern class Pattern; class UncompressedPattern; - - /** Convenience typedef for a dictionary entry. */ - typedef std::array<uint8_t, sizeof(T)> DictionaryEntry; + template <T mask> + class MaskedPattern; /** * Create a factory to determine if input matches a pattern. The if else @@ -420,4 +422,62 @@ class DictionaryCompressor<T>::UncompressedPattern } }; +/** + * A pattern that compares masked values against dictionary entries. If + * the masked dictionary entry matches perfectly the masked value to be + * compressed, there is a pattern match. + * + * For example, if the mask is 0xFF00 (that is, this pattern matches the MSB), + * the value (V) 0xFF20 is being compressed, and the dictionary contains + * the value (D) 0xFF03, this is a match (V & mask == 0xFF00 == D & mask), + * and 0x0020 is added to the list of unmatched bits. + * + * @tparam mask A mask containing the bits that must match. + */ +template <class T> +template <T mask> +class DictionaryCompressor<T>::MaskedPattern + : public DictionaryCompressor<T>::Pattern +{ + private: + static_assert(mask != 0, "The pattern's value mask must not be zero. Use " + "the uncompressed pattern instead."); + + /** A copy of the bits that do not belong to the mask. */ + const T bits; + + public: + MaskedPattern(const int number, + const uint64_t code, + const uint64_t metadata_length, + const int match_location, + const DictionaryEntry bytes, + const bool allocate = true) + : DictionaryCompressor<T>::Pattern(number, code, metadata_length, + popCount(~mask) / 8, match_location, allocate), + bits(DictionaryCompressor<T>::fromDictionaryEntry(bytes) & ~mask) + { + } + + static bool + isPattern(const DictionaryEntry& bytes, const DictionaryEntry& dict_bytes, + const int match_location) + { + const T masked_bytes = + DictionaryCompressor<T>::fromDictionaryEntry(bytes) & mask; + const T masked_dict_bytes = + DictionaryCompressor<T>::fromDictionaryEntry(dict_bytes) & mask; + return (match_location >= 0) && (masked_bytes == masked_dict_bytes); + } + + DictionaryEntry + decompress(const DictionaryEntry dict_bytes) const override + { + const T masked_dict_bytes = + DictionaryCompressor<T>::fromDictionaryEntry(dict_bytes) & mask; + return DictionaryCompressor<T>::toDictionaryEntry( + bits | masked_dict_bytes); + } +}; + #endif //__MEM_CACHE_COMPRESSORS_DICTIONARY_COMPRESSOR_HH__ |