#include <tage_sc_l.hh>

Inheritance diagram for TAGE_SC_L_TAGE:

Classes
struct	BranchInfo

Public Member Functions
virtual TAGEBase::BranchInfo *	makeBranchInfo () override

	TAGE_SC_L_TAGE (const TAGE_SC_L_TAGEParams *p)

void	calculateParameters () override
	Calculates the history lengths and some other paramters in derived classes. More...

void	buildTageTables () override
	Instantiates the TAGE table entries. More...

void	calculateIndicesAndTags (ThreadID tid, Addr branch_pc, TAGEBase::BranchInfo *bi) override
	On a prediction, calculates the TAGE indices and tags for all the different history lengths. More...

unsigned	getUseAltIdx (TAGEBase::BranchInfo *bi, Addr branch_pc) override
	Calculation of the index for useAltPredForNewlyAllocated On this base TAGE implementation it is always 0. More...

void	updateHistories (ThreadID tid, Addr branch_pc, bool taken, TAGEBase::BranchInfo *b, bool speculative, const StaticInstPtr &inst, Addr target) override
	(Speculatively) updates global histories (path and direction). More...

int	bindex (Addr pc_in) const override
	Computes the index used to access the bimodal table. More...

int	gindex (ThreadID tid, Addr pc, int bank) const override
	Computes the index used to access a partially tagged table. More...

virtual int	gindex_ext (int index, int bank) const =0

int	F (int phist, int size, int bank) const override
	Utility function to shuffle the path history depending on which tagged table we are accessing. More...

virtual uint16_t	gtag (ThreadID tid, Addr pc, int bank) const override=0
	Computes the partial tag of a tagged table. More...

void	squash (ThreadID tid, bool taken, TAGEBase::BranchInfo *bi, Addr target) override
	Restores speculatively updated path and direction histories. More...

void	updatePathAndGlobalHistory (ThreadHistory &tHist, int brtype, bool taken, Addr branch_pc, Addr target)

void	adjustAlloc (bool &alloc, bool taken, bool pred_taken) override
	Extra calculation to tell whether TAGE allocaitons may happen or not on an update For this base TAGE implementation it does nothing. More...

virtual void	handleAllocAndUReset (bool alloc, bool taken, TAGEBase::BranchInfo *bi, int nrand) override=0
	Handles Allocation and U bits reset on an update. More...

void	handleUReset () override
	Handles the U bits reset. More...

virtual void	handleTAGEUpdate (Addr branch_pc, bool taken, TAGEBase::BranchInfo *bi) override=0
	Handles the update of the TAGE entries. More...

int	calcDep (TAGEBase::BranchInfo *bi)

bool	getBimodePred (Addr branch_pc, TAGEBase::BranchInfo *tage_bi) const override
	Get a branch prediction from the bimodal predictor. More...

void	extraAltCalc (TAGEBase::BranchInfo *bi) override
	Extra steps for calculating altTaken For this base TAGE class it does nothing. More...

Public Member Functions inherited from TAGEBase
	TAGEBase (const TAGEBaseParams *p)

void	regStats () override
	Callback to set stat parameters. More...

void	init () override
	init() is called after all C++ SimObjects have been created and all ports are connected. More...

void	baseUpdate (Addr pc, bool taken, BranchInfo *bi)
	Updates the bimodal predictor. More...

void	updateGHist (uint8_t &h, bool dir, uint8_t tab, int &PT)
	(Speculatively) updates the global branch history. More...

void	update (ThreadID tid, Addr branch_pc, bool taken, BranchInfo *bi)
	Update TAGE. More...

virtual void	condBranchUpdate (ThreadID tid, Addr branch_pc, bool taken, BranchInfo *bi, int nrand, Addr corrTarget, bool pred, bool preAdjustAlloc=false)
	Update TAGE for conditional branches. More...

bool	tagePredict (ThreadID tid, Addr branch_pc, bool cond_branch, BranchInfo *bi)
	TAGE prediction called from TAGE::predict. More...

virtual void	updateStats (bool taken, BranchInfo *bi)
	Update the stats. More...

virtual void	resetUctr (uint8_t &u)
	Algorithm for resetting a single U counter. More...

virtual bool	isHighConfidence (BranchInfo *bi) const

void	btbUpdate (ThreadID tid, Addr branch_addr, BranchInfo *&bi)

unsigned	getGHR (ThreadID tid, BranchInfo *bi) const

int8_t	getCtr (int hitBank, int hitBankIndex) const

unsigned	getTageCtrBits () const

int	getPathHist (ThreadID tid) const

bool	isSpeculativeUpdateEnabled () const

size_t	getSizeInBits () const

Public Member Functions inherited from SimObject
virtual	~SimObject ()

virtual const std::string	name () const

virtual void	loadState (CheckpointIn &cp)
	loadState() is called on each SimObject when restoring from a checkpoint. More...

virtual void	initState ()
	initState() is called on each SimObject when not restoring from a checkpoint. More...

virtual void	regProbePoints ()
	Register probe points for this object. More...

virtual void	regProbeListeners ()
	Register probe listeners for this object. More...

ProbeManager *	getProbeManager ()
	Get the probe manager for this object. More...

virtual Port &	getPort (const std::string &if_name, PortID idx=InvalidPortID)
	Get a port with a given name and index. More...

virtual void	startup ()
	startup() is the final initialization call before simulation. More...

DrainState	drain () override
	Provide a default implementation of the drain interface for objects that don't need draining. More...

virtual void	memWriteback ()
	Write back dirty buffers to memory using functional writes. More...

virtual void	memInvalidate ()
	Invalidate the contents of memory buffers. More...

void	serialize (CheckpointOut &cp) const override
	Serialize an object. More...

void	unserialize (CheckpointIn &cp) override
	Unserialize an object. More...

const Params *	params () const

	SimObject (const Params *_params)

Public Member Functions inherited from EventManager
EventQueue *	eventQueue () const

void	schedule (Event &event, Tick when)

void	deschedule (Event &event)

void	reschedule (Event &event, Tick when, bool always=false)

void	schedule (Event *event, Tick when)

void	deschedule (Event *event)

void	reschedule (Event *event, Tick when, bool always=false)

void	wakeupEventQueue (Tick when=(Tick) -1)

void	setCurTick (Tick newVal)

	EventManager (EventManager &em)

	EventManager (EventManager *em)

	EventManager (EventQueue *eq)

Public Member Functions inherited from Serializable
	Serializable ()

virtual	~Serializable ()

void	serializeSection (CheckpointOut &cp, const char *name) const
	Serialize an object into a new section. More...

void	serializeSection (CheckpointOut &cp, const std::string &name) const

void	unserializeSection (CheckpointIn &cp, const char *name)
	Unserialize an a child object. More...

void	unserializeSection (CheckpointIn &cp, const std::string &name)

Public Member Functions inherited from Drainable
DrainState	drainState () const
	Return the current drain state of an object. More...

virtual void	notifyFork ()
	Notify a child process of a fork. More...

Public Member Functions inherited from Stats::Group
	Group (Group parent, const char name=nullptr)
	Construct a new statistics group. More...

virtual	~Group ()

virtual void	resetStats ()
	Callback to reset stats. More...

virtual void	preDumpStats ()
	Callback before stats are dumped. More...

void	addStat (Stats::Info *info)
	Register a stat with this group. More...

const std::map< std::string, Group * > &	getStatGroups () const
	Get all child groups associated with this object. More...

const std::vector< Info * > &	getStats () const
	Get all stats associated with this object. More...

void	addStatGroup (const char name, Group block)
	Add a stat block as a child of this block. More...

const Info *	resolveStat (std::string name) const
	Resolve a stat by its name within this group. More...

	Group ()=delete

	Group (const Group &)=delete

Group &	operator= (const Group &)=delete

Private Attributes
const unsigned	firstLongTagTable

const unsigned	longTagsSize

const unsigned	shortTagsSize

const unsigned	logTagTableSize

const unsigned	shortTagsTageFactor

const unsigned	longTagsTageFactor

const bool	truncatePathHist

Additional Inherited Members
Public Types inherited from TAGEBase
enum	{ BIMODAL_ONLY = 0, TAGE_LONGEST_MATCH, BIMODAL_ALT_MATCH, TAGE_ALT_MATCH, LAST_TAGE_PROVIDER_TYPE = TAGE_ALT_MATCH }

Public Types inherited from SimObject
typedef SimObjectParams	Params

Static Public Member Functions inherited from TAGEBase
template<typename T >
static void	ctrUpdate (T &ctr, bool taken, int nbits)
	Updates a direction counter based on the actual branch outcome. More...

static void	unsignedCtrUpdate (uint8_t &ctr, bool up, unsigned nbits)
	Updates an unsigned counter based on up/down parameter. More...

Static Public Member Functions inherited from SimObject
static void	serializeAll (CheckpointOut &cp)
	Serialize all SimObjects in the system. More...

static SimObject *	find (const char *name)
	Find the SimObject with the given name and return a pointer to it. More...

Static Public Member Functions inherited from Serializable
static const std::string &	currentSection ()
	Gets the fully-qualified name of the active section. More...

static void	serializeAll (const std::string &cpt_dir)

static void	unserializeGlobals (CheckpointIn &cp)

Protected Member Functions inherited from TAGEBase
virtual void	initFoldedHistories (ThreadHistory &history)
	Initialization of the folded histories. More...

Protected Member Functions inherited from Drainable
	Drainable ()

virtual	~Drainable ()

virtual void	drainResume ()
	Resume execution after a successful drain. More...

void	signalDrainDone () const
	Signal that an object is drained. More...

Protected Attributes inherited from TAGEBase
const unsigned	logRatioBiModalHystEntries

const unsigned	nHistoryTables

const unsigned	tagTableCounterBits

const unsigned	tagTableUBits

const unsigned	histBufferSize

const unsigned	minHist

const unsigned	maxHist

const unsigned	pathHistBits

std::vector< unsigned >	tagTableTagWidths

std::vector< int >	logTagTableSizes

std::vector< bool >	btablePrediction

std::vector< bool >	btableHysteresis

TageEntry **	gtable

std::vector< ThreadHistory >	threadHistory

int *	histLengths

int *	tableIndices

int *	tableTags

std::vector< int8_t >	useAltPredForNewlyAllocated

int64_t	tCounter

uint64_t	logUResetPeriod

const int64_t	initialTCounterValue

unsigned	numUseAltOnNa

unsigned	useAltOnNaBits

unsigned	maxNumAlloc

std::vector< bool >	noSkip

const bool	speculativeHistUpdate

const unsigned	instShiftAmt

bool	initialized

Stats::Scalar	tageLongestMatchProviderCorrect

Stats::Scalar	tageAltMatchProviderCorrect

Stats::Scalar	bimodalAltMatchProviderCorrect

Stats::Scalar	tageBimodalProviderCorrect

Stats::Scalar	tageLongestMatchProviderWrong

Stats::Scalar	tageAltMatchProviderWrong

Stats::Scalar	bimodalAltMatchProviderWrong

Stats::Scalar	tageBimodalProviderWrong

Stats::Scalar	tageAltMatchProviderWouldHaveHit

Stats::Scalar	tageLongestMatchProviderWouldHaveHit

Stats::Vector	tageLongestMatchProvider

Stats::Vector	tageAltMatchProvider

Protected Attributes inherited from SimObject
const SimObjectParams *	_params
	Cached copy of the object parameters. More...

Protected Attributes inherited from EventManager
EventQueue *	eventq
	A pointer to this object's event queue. More...

Detailed Description

Definition at line 52 of file tage_sc_l.hh.

Constructor & Destructor Documentation

◆ TAGE_SC_L_TAGE()

TAGE_SC_L_TAGE::TAGE_SC_L_TAGE ( const TAGE_SC_L_TAGEParams * p )

inline

Definition at line 79 of file tage_sc_l.hh.

References adjustAlloc(), ArmISA::b, PowerISA::bi, bindex(), buildTageTables(), calcDep(), calculateIndicesAndTags(), calculateParameters(), extraAltCalc(), F(), getBimodePred(), getUseAltIdx(), gindex(), gindex_ext(), gtag(), handleAllocAndUReset(), handleTAGEUpdate(), handleUReset(), MipsISA::index, MipsISA::pc, squash(), updateHistories(), and updatePathAndGlobalHistory().

Member Function Documentation

◆ adjustAlloc()

void TAGE_SC_L_TAGE::adjustAlloc	(	bool &	alloc,
		bool	taken,
		bool	pred_taken
	)

overridevirtual

Extra calculation to tell whether TAGE allocaitons may happen or not on an update For this base TAGE implementation it does nothing.

Reimplemented from TAGEBase.

Definition at line 296 of file tage_sc_l.cc.

References Random::random(), and random_mt.

Referenced by TAGE_SC_L_TAGE().

◆ bindex()

int TAGE_SC_L_TAGE::bindex ( Addr pc_in ) const

overridevirtual

Computes the index used to access the bimodal table.

Parameters

pc_in The unshifted branch PC.

Reimplemented from TAGEBase.

Definition at line 223 of file tage_sc_l.cc.

References BPredUnit::instShiftAmt, and ULL.

Referenced by TAGE_SC_L_TAGE().

◆ buildTageTables()

void TAGE_SC_L_TAGE::buildTageTables ( )

overridevirtual

Instantiates the TAGE table entries.

Reimplemented from TAGEBase.

Definition at line 111 of file tage_sc_l.cc.

References ArmISA::i.

Referenced by TAGE_SC_L_TAGE().

◆ calcDep()

int TAGE_SC_L_TAGE::calcDep ( TAGEBase::BranchInfo * bi )

Definition at line 305 of file tage_sc_l.cc.

References ArmISA::a, TAGEBase::BranchInfo::hitBank, Random::random(), and random_mt.

Referenced by TAGE_SC_L_TAGE().

◆ calculateIndicesAndTags()

void TAGE_SC_L_TAGE::calculateIndicesAndTags	(	ThreadID	tid,
		Addr	branch_pc,
		TAGEBase::BranchInfo *	bi
	)

overridevirtual

On a prediction, calculates the TAGE indices and tags for all the different history lengths.

Reimplemented from TAGEBase.

Definition at line 128 of file tage_sc_l.cc.

References ArmISA::i, ArmISA::t, TAGEBase::BranchInfo::tableIndices, and TAGEBase::BranchInfo::tableTags.

Referenced by TAGE_SC_L_TAGE().

◆ calculateParameters()

void TAGE_SC_L_TAGE::calculateParameters ( )

overridevirtual

Calculates the history lengths and some other paramters in derived classes.

Reimplemented from TAGEBase.

Definition at line 78 of file tage_sc_l.cc.

References ArmISA::i.

Referenced by TAGE_SC_L_TAGE().

◆ extraAltCalc()

void TAGE_SC_L_TAGE::extraAltCalc ( TAGEBase::BranchInfo * bi )

overridevirtual

Extra steps for calculating altTaken For this base TAGE class it does nothing.

Reimplemented from TAGEBase.

Definition at line 356 of file tage_sc_l.cc.

References TAGEBase::BranchInfo::altBank, TAGEBase::BranchInfo::altBankIndex, TAGE_SC_L_TAGE::BranchInfo::altConf, and PowerISA::bi.

Referenced by TAGE_SC_L_TAGE().

◆ F()

int TAGE_SC_L_TAGE::F	(	int	phist,
		int	size,
		int	bank
	)		const

overridevirtual

Utility function to shuffle the path history depending on which tagged table we are accessing.

Parameters

phist	The path history.
size	Number of path history bits to use.
bank	The partially tagged table to access.

Reimplemented from TAGEBase.

Definition at line 199 of file tage_sc_l.cc.

References ArmISA::a, ArmISA::a1, and ULL.

Referenced by TAGE_SC_L_TAGE().

◆ getBimodePred()

bool TAGE_SC_L_TAGE::getBimodePred	(	Addr	pc,
		TAGEBase::BranchInfo *	bi
	)		const

overridevirtual

Get a branch prediction from the bimodal predictor.

Parameters

pc	The unshifted branch PC.
bi	Pointer to information on the prediction.

Reimplemented from TAGEBase.

Definition at line 340 of file tage_sc_l.cc.

References TAGE_SC_L_TAGE::BranchInfo::altConf, PowerISA::bi, TAGEBase::BranchInfo::bimodalIndex, TAGEBase::getBimodePred(), TAGE_SC_L_TAGE::BranchInfo::highConf, TAGE_SC_L_TAGE::BranchInfo::lowConf, and TAGE_SC_L_TAGE::BranchInfo::medConf.

Referenced by TAGE_SC_L_TAGE().

◆ getUseAltIdx()

unsigned TAGE_SC_L_TAGE::getUseAltIdx	(	TAGEBase::BranchInfo *	bi,
		Addr	branch_pc
	)

overridevirtual

Calculation of the index for useAltPredForNewlyAllocated On this base TAGE implementation it is always 0.

Reimplemented from TAGEBase.

Definition at line 171 of file tage_sc_l.cc.

References TAGE_SC_L_TAGE::BranchInfo::altConf, PowerISA::bi, TAGEBase::BranchInfo::hitBank, and ArmISA::tbi.

Referenced by TAGE_SC_L_TAGE().

◆ gindex()

int TAGE_SC_L_TAGE::gindex	(	ThreadID	tid,
		Addr	pc,
		int	bank
	)		const

overridevirtual

Computes the index used to access a partially tagged table.

Parameters

tid	The thread ID used to select the global histories to use.
pc	The unshifted branch PC.
bank	The partially tagged table to access.

Reimplemented from TAGEBase.

Definition at line 180 of file tage_sc_l.cc.

References MipsISA::index, MipsISA::pc, and ULL.

Referenced by TAGE_SC_L_TAGE().

◆ gindex_ext()

virtual int TAGE_SC_L_TAGE::gindex_ext	(	int	index,
		int	bank
	)		const

pure virtual

Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.

Referenced by TAGE_SC_L_TAGE().

◆ gtag()

virtual uint16_t TAGE_SC_L_TAGE::gtag	(	ThreadID	tid,
		Addr	pc,
		int	bank
	)		const

overridepure virtual

Computes the partial tag of a tagged table.

Parameters

tid	the thread ID used to select the global histories to use.
pc	The unshifted branch PC.
bank	The partially tagged table to access.

Reimplemented from TAGEBase.

Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.

Referenced by TAGE_SC_L_TAGE().

◆ handleAllocAndUReset()

virtual void TAGE_SC_L_TAGE::handleAllocAndUReset	(	bool	alloc,
		bool	taken,
		TAGEBase::BranchInfo *	bi,
		int	nrand
	)

overridepure virtual

Handles Allocation and U bits reset on an update.

Reimplemented from TAGEBase.

Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.

Referenced by TAGE_SC_L_TAGE().

◆ handleTAGEUpdate()

virtual void TAGE_SC_L_TAGE::handleTAGEUpdate	(	Addr	branch_pc,
		bool	taken,
		TAGEBase::BranchInfo *	bi
	)

overridepure virtual

Handles the update of the TAGE entries.

Reimplemented from TAGEBase.

Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.

Referenced by TAGE_SC_L_TAGE().

◆ handleUReset()

void TAGE_SC_L_TAGE::handleUReset ( )

overridevirtual

Handles the U bits reset.

Reimplemented from TAGEBase.

Definition at line 316 of file tage_sc_l.cc.

References ArmISA::j, ArmISA::u, and ULL.

Referenced by TAGE_SC_L_TAGE().

◆ makeBranchInfo()

TAGEBase::BranchInfo * TAGE_SC_L_TAGE::makeBranchInfo ( )

overridevirtual

Reimplemented from TAGEBase.

Definition at line 73 of file tage_sc_l.cc.

Referenced by TAGE_SC_L_TAGE::BranchInfo::~BranchInfo().

◆ squash()

void TAGE_SC_L_TAGE::squash	(	ThreadID	tid,
		bool	taken,
		TAGEBase::BranchInfo *	bi,
		Addr	target
	)

overridevirtual

Restores speculatively updated path and direction histories.

Also recomputes compressed (folded) histories based on the correct branch outcome. This version of squash() is called once on a branch misprediction.

Parameters

tid	The Thread ID to select the histories to rollback.
taken	The correct branch outcome.
bp_history	Wrapping pointer to BranchInfo (to allow storing derived class prediction information in the base class).
target	The correct branch target

Postcondition: bp_history points to valid memory.

Reimplemented from TAGEBase.

Definition at line 289 of file tage_sc_l.cc.

References fatal.

Referenced by TAGE_SC_L_TAGE().

◆ updateHistories()

void TAGE_SC_L_TAGE::updateHistories	(	ThreadID	tid,
		Addr	branch_pc,
		bool	taken,
		TAGEBase::BranchInfo *	b,
		bool	speculative,
		const StaticInstPtr &	inst,
		Addr	target
	)

overridevirtual

(Speculatively) updates global histories (path and direction).

Also recomputes compressed (folded) histories based on the branch direction.

Parameters

tid	The thread ID to select the histories to update.
branch_pc	The unshifted branch PC.
taken	(Predicted) branch direction.
b	Wrapping pointer to BranchInfo (to allow storing derived class prediction information in the base class).

Reimplemented from TAGEBase.

Definition at line 265 of file tage_sc_l.cc.

References DPRINTF, StaticInst::isDirectCtrl(), StaticInst::isUncondCtrl(), TAGEBase::ThreadHistory::pathHist, and TAGEBase::ThreadHistory::ptGhist.

Referenced by TAGE_SC_L_TAGE().

◆ updatePathAndGlobalHistory()

void TAGE_SC_L_TAGE::updatePathAndGlobalHistory	(	ThreadHistory &	tHist,
		int	brtype,
		bool	taken,
		Addr	branch_pc,
		Addr	target
	)

Definition at line 230 of file tage_sc_l.cc.

References TAGEBase::ThreadHistory::computeIndices, TAGEBase::ThreadHistory::computeTags, TAGEBase::ThreadHistory::gHist, TAGEBase::ThreadHistory::globalHistory, ArmISA::i, BPredUnit::instShiftAmt, Serializable::path, TAGEBase::ThreadHistory::pathHist, TAGEBase::ThreadHistory::ptGhist, ArmISA::t, ULL, and TAGEBase::FoldedHistory::update().

Referenced by TAGE_SC_L_TAGE().

Member Data Documentation

◆ firstLongTagTable

const unsigned TAGE_SC_L_TAGE::firstLongTagTable

private

Definition at line 53 of file tage_sc_l.hh.

◆ logTagTableSize

const unsigned TAGE_SC_L_TAGE::logTagTableSize

private

Definition at line 57 of file tage_sc_l.hh.

◆ longTagsSize

const unsigned TAGE_SC_L_TAGE::longTagsSize

private

Definition at line 54 of file tage_sc_l.hh.

◆ longTagsTageFactor

const unsigned TAGE_SC_L_TAGE::longTagsTageFactor

private

Definition at line 60 of file tage_sc_l.hh.

◆ shortTagsSize

const unsigned TAGE_SC_L_TAGE::shortTagsSize

private

Definition at line 55 of file tage_sc_l.hh.

◆ shortTagsTageFactor

const unsigned TAGE_SC_L_TAGE::shortTagsTageFactor

private

Definition at line 59 of file tage_sc_l.hh.

◆ truncatePathHist

const bool TAGE_SC_L_TAGE::truncatePathHist

private

Definition at line 62 of file tage_sc_l.hh.

The documentation for this class was generated from the following files:

cpu/pred/tage_sc_l.hh
cpu/pred/tage_sc_l.cc

Classes

Public Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ TAGE_SC_L_TAGE()

Member Function Documentation

◆ adjustAlloc()

◆ bindex()

◆ buildTageTables()

◆ calcDep()

◆ calculateIndicesAndTags()

◆ calculateParameters()

◆ extraAltCalc()

◆ F()

◆ getBimodePred()

◆ getUseAltIdx()

◆ gindex()

◆ gindex_ext()

◆ gtag()

◆ handleAllocAndUReset()

◆ handleTAGEUpdate()

◆ handleUReset()

◆ makeBranchInfo()

◆ squash()

◆ updateHistories()

◆ updatePathAndGlobalHistory()

Member Data Documentation

◆ firstLongTagTable

◆ logTagTableSize

◆ longTagsSize

◆ longTagsTageFactor

◆ shortTagsSize

◆ shortTagsTageFactor

◆ truncatePathHist