A pattern that checks whether the value is an N bits sign-extended value, that is, all the MSB starting from the Nth are equal to the (N-1)th bit. More...

#include <dictionary_compressor.hh>

Inheritance diagram for gem5::compression::DictionaryCompressor< T >::SignExtendedPattern< N >:

Public Member Functions
	SignExtendedPattern (const int number, const uint64_t code, const uint64_t metadata_length, const DictionaryEntry bytes, const bool allocate=false)
DictionaryEntry	decompress (const DictionaryEntry dict_bytes) const override
	Decompress the pattern.
Public Member Functions inherited from gem5::compression::DictionaryCompressor< T >::Pattern
	Pattern (const int number, const uint64_t code, const uint64_t metadata_length, const uint64_t num_unmatched_bits, const int match_location, const bool allocate=true)
	Default constructor.
virtual	~Pattern ()=default
	Default destructor.
int	getPatternNumber () const
	Get enum number associated to this pattern.
uint8_t	getCode () const
	Get code of this pattern.
uint8_t	getMatchLocation () const
	Get the index of the dictionary match location.
virtual std::size_t	getSizeBits () const
	Get size, in bits, of the pattern (excluding prefix).
bool	shouldAllocate () const
	Determine if pattern allocates a dictionary entry.
std::string	print () const
	Extract pattern's information to a string.

Static Public Member Functions
static bool	isPattern (const DictionaryEntry &bytes, const DictionaryEntry &dict_bytes, const int match_location)

Private Attributes
const T	bits: N
	The non-extended original value.

Additional Inherited Members
Protected Attributes inherited from gem5::compression::DictionaryCompressor< T >::Pattern
const int	patternNumber
	Pattern enum number.
const uint8_t	code
	Code associated to the pattern.
const uint8_t	length
	Length, in bits, of the code and match location.
const uint8_t	numUnmatchedBits
	Number of unmatched bits.
const int	matchLocation
	Index representing the the match location.
const bool	allocate
	Wether the pattern allocates a dictionary entry or not.

Detailed Description

template<class T>
template<unsigned N>
class gem5::compression::DictionaryCompressor< T >::SignExtendedPattern< N >

A pattern that checks whether the value is an N bits sign-extended value, that is, all the MSB starting from the Nth are equal to the (N-1)th bit.

Therefore, if N = 8, and T has 16 bits, the values within the ranges [0x0000, 0x007F] and [0xFF80, 0xFFFF] would match this pattern.

Template Parameters

N	The number of bits in the non-extended original value. It must fit in a dictionary entry.

Definition at line 756 of file dictionary_compressor.hh.

Constructor & Destructor Documentation

◆ SignExtendedPattern()

template<class T>

template<unsigned N>

gem5::compression::DictionaryCompressor< T >::SignExtendedPattern< N >::SignExtendedPattern	(	const int	number,
		const uint64_t	code,
		const uint64_t	metadata_length,
		const DictionaryEntry	bytes,
		const bool	allocate = false )

inline

Definition at line 767 of file dictionary_compressor.hh.

References gem5::compression::DictionaryCompressor< T >::Pattern::allocate, bits, gem5::compression::DictionaryCompressor< T >::Pattern::code, gem5::compression::DictionaryCompressor< T >::DictionaryCompressor(), gem5::compression::DictionaryCompressor< T >::fromDictionaryEntry(), gem5::ArmISA::mask, and gem5::compression::DictionaryCompressor< T >::Pattern::Pattern().

Member Function Documentation

◆ decompress()

template<class T>

template<unsigned N>

DictionaryEntry gem5::compression::DictionaryCompressor< T >::SignExtendedPattern< N >::decompress ( const DictionaryEntry dict_bytes ) const

inlineoverridevirtual

Decompress the pattern.

Each pattern has its own way of interpreting its data.

Parameters

dict_bytes The bytes in the corresponding matching entry.

Returns: The decompressed pattern.

Implements gem5::compression::DictionaryCompressor< T >::Pattern.

Definition at line 787 of file dictionary_compressor.hh.

References bits, gem5::sext(), and gem5::compression::DictionaryCompressor< T >::toDictionaryEntry().

◆ isPattern()

template<class T>

template<unsigned N>

bool gem5::compression::DictionaryCompressor< T >::SignExtendedPattern< N >::isPattern	(	const DictionaryEntry &	bytes,
		const DictionaryEntry &	dict_bytes,
		const int	match_location )