diff options
| -rw-r--r-- | src/mem/cache/compressors/cpack.hh | 40 | ||||
| -rw-r--r-- | src/mem/cache/compressors/dictionary_compressor.hh | 58 |
2 files changed, 64 insertions, 34 deletions
diff --git a/src/mem/cache/compressors/cpack.hh b/src/mem/cache/compressors/cpack.hh index 7b10ac3e7..32178b0ba 100644 --- a/src/mem/cache/compressors/cpack.hh +++ b/src/mem/cache/compressors/cpack.hh @@ -124,24 +124,13 @@ class CPack : public DictionaryCompressor<uint32_t> ~CPack() {}; }; -class CPack::PatternZZZZ : public DictionaryCompressor::Pattern +class CPack::PatternZZZZ : public MaskedValuePattern<0, 0xFFFFFFFF> { public: PatternZZZZ(const DictionaryEntry bytes, const int match_location) - : Pattern(ZZZZ, 0x0, 2, 0, 0, false) {} - - static bool isPattern(const DictionaryEntry& bytes, - const DictionaryEntry& dict_bytes, - const int match_location) + : MaskedValuePattern<0, 0xFFFFFFFF>(ZZZZ, 0x0, 2, match_location, + bytes) { - return (bytes[3] == 0) && (bytes[2] == 0) && (bytes[1] == 0) && - (bytes[0] == 0); - } - - DictionaryEntry - decompress(const DictionaryEntry dict_bytes) const override - { - return {0, 0, 0, 0}; } }; @@ -172,30 +161,13 @@ class CPack::PatternMMXX : public MaskedPattern<0xFFFF0000> } }; -class CPack::PatternZZZX : public DictionaryCompressor::Pattern +class CPack::PatternZZZX : public MaskedValuePattern<0, 0xFFFFFF00> { - private: - /** - * A copy of the unmatched byte. - */ - const uint8_t byte; - public: PatternZZZX(const DictionaryEntry bytes, const int match_location) - : Pattern(ZZZX, 0xD, 4, 1, 0, false), byte(bytes[0]) {} - - static bool isPattern(const DictionaryEntry& bytes, - const DictionaryEntry& dict_bytes, - const int match_location) - { - return (bytes[3] == 0) && (bytes[2] == 0) && (bytes[1] == 0) && - (bytes[0] != 0); - } - - DictionaryEntry - decompress(const DictionaryEntry dict_bytes) const override + : MaskedValuePattern<0, 0xFFFFFF00>(ZZZX, 0xD, 4, match_location, + bytes) { - return {byte, 0, 0, 0}; } }; diff --git a/src/mem/cache/compressors/dictionary_compressor.hh b/src/mem/cache/compressors/dictionary_compressor.hh index 3c828f040..b519bb466 100644 --- a/src/mem/cache/compressors/dictionary_compressor.hh +++ b/src/mem/cache/compressors/dictionary_compressor.hh @@ -125,6 +125,8 @@ class DictionaryCompressor : public BaseDictionaryCompressor class UncompressedPattern; template <T mask> class MaskedPattern; + template <T value, T mask> + class MaskedValuePattern; /** * Create a factory to determine if input matches a pattern. The if else @@ -480,4 +482,60 @@ class DictionaryCompressor<T>::MaskedPattern } }; +/** + * A pattern that compares masked values to a masked portion of a fixed value. + * If all the masked bits match the provided non-dictionary value, there is a + * pattern match. + * + * For example, assume the mask is 0xFF00 (that is, this pattern matches the + * MSB), and we are searching for data containing only ones (i.e., the fixed + * value is 0xFFFF). + * If the value (V) 0xFF20 is being compressed, this is a match (V & mask == + * 0xFF00 == 0xFFFF & mask), and 0x20 is added to the list of unmatched bits. + * If the value (V2) 0x0120 is being compressed, this is not a match + * ((V2 & mask == 0x0100) != (0xFF00 == 0xFFFF & mask). + * + * @tparam value The value that is being matched against. + * @tparam mask A mask containing the bits that must match the given value. + */ +template <class T> +template <T value, T mask> +class DictionaryCompressor<T>::MaskedValuePattern + : public MaskedPattern<mask> +{ + private: + static_assert(mask != 0, "The pattern's value mask must not be zero."); + + public: + MaskedValuePattern(const int number, + const uint64_t code, + const uint64_t metadata_length, + const int match_location, + const DictionaryEntry bytes, + const bool allocate = false) + : MaskedPattern<mask>(number, code, metadata_length, match_location, + bytes, allocate) + { + } + + static bool + isPattern(const DictionaryEntry& bytes, const DictionaryEntry& dict_bytes, + const int match_location) + { + // Compare the masked fixed value to the value being checked for + // patterns. Since the dictionary is not being used the match_location + // is irrelevant. + const T masked_bytes = + DictionaryCompressor<T>::fromDictionaryEntry(bytes) & mask; + return ((value & mask) == masked_bytes); + } + + DictionaryEntry + decompress(const DictionaryEntry dict_bytes) const override + { + return MaskedPattern<mask>::decompress( + DictionaryCompressor<T>::toDictionaryEntry(value)); + } +}; + #endif //__MEM_CACHE_COMPRESSORS_DICTIONARY_COMPRESSOR_HH__ |