#include <ltage.hh>

Inheritance diagram for LTAGE:

Classes
struct	LTageBranchInfo

Public Member Functions
	LTAGE (const LTAGEParams *params)

void	squash (ThreadID tid, void *bp_history) override

void	update (ThreadID tid, Addr branch_addr, bool taken, void *bp_history, bool squashed, const StaticInstPtr &inst, Addr corrTarget) override
	Updates the BP with taken/not taken information. More...

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

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

Public Member Functions inherited from TAGE
	TAGE (const TAGEParams *params)

void	uncondBranch (ThreadID tid, Addr br_pc, void *&bp_history) override

bool	lookup (ThreadID tid, Addr branch_addr, void *&bp_history) override
	Looks up a given PC in the BP to see if it is taken or not taken. More...

void	btbUpdate (ThreadID tid, Addr branch_addr, void *&bp_history) override
	If a branch is not taken, because the BTB address is invalid or missing, this function sets the appropriate counter in the global and local predictors to not taken. More...

void	update (ThreadID tid, Addr branch_addr, bool taken, void *bp_history, bool squashed, const StaticInstPtr &inst, Addr corrTarget) override
	Updates the BP with taken/not taken information. More...

Public Member Functions inherited from BPredUnit
	BPredUnit (const Params *p)

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

void	drainSanityCheck () const
	Perform sanity checks after a drain. More...

bool	predict (const StaticInstPtr &inst, const InstSeqNum &seqNum, TheISA::PCState &pc, ThreadID tid)
	Predicts whether or not the instruction is a taken branch, and the target of the branch if it is taken. More...

void	update (const InstSeqNum &done_sn, ThreadID tid)
	Tells the branch predictor to commit any updates until the given sequence number. More...

void	squash (const InstSeqNum &squashed_sn, ThreadID tid)
	Squashes all outstanding updates until a given sequence number. More...

void	squash (const InstSeqNum &squashed_sn, const TheISA::PCState &corr_target, bool actually_taken, ThreadID tid)
	Squashes all outstanding updates until a given sequence number, and corrects that sn's update with the proper address and taken/not taken. More...

bool	BTBValid (Addr instPC)
	Looks up a given PC in the BTB to see if a matching entry exists. More...

TheISA::PCState	BTBLookup (Addr instPC)
	Looks up a given PC in the BTB to get the predicted target. More...

void	BTBUpdate (Addr instPC, const TheISA::PCState &target)
	Updates the BTB with the target of a branch. More...

void	dump ()

Public Member Functions inherited from SimObject
const Params *	params () const

	SimObject (const Params *_params)

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	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...

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)
	This function is not needed by the usual gem5 event loop but may be necessary in derived EventQueues which host gem5 on other schedulers. More...

void	setCurTick (Tick newVal)

	EventManager (EventManager &em)
	Event manger manages events in the event queue. More...

	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

Protected Types
enum	{ LOOP = TAGEBase::LAST_TAGE_PROVIDER_TYPE + 1, LAST_LTAGE_PROVIDER_TYPE = LOOP }

Protected Member Functions
bool	predict (ThreadID tid, Addr branch_pc, bool cond_branch, void *&b) override
	Get a branch prediction from LTAGE. More...

Protected Member Functions inherited from BPredUnit
ProbePoints::PMUUPtr	pmuProbePoint (const char *name)
	Helper method to instantiate probe points belonging to this object. 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
LoopPredictor *	loopPredictor
	The loop predictor object. More...

Protected Attributes inherited from TAGE
TAGEBase *	tage

Protected Attributes inherited from BPredUnit
const unsigned	instShiftAmt
	Number of bits to shift instructions by for predictor addresses. More...

ProbePoints::PMUUPtr	ppBranches
	Branches seen by the branch predictor. More...

ProbePoints::PMUUPtr	ppMisses
	Miss-predicted branches. More...

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...

Additional Inherited Members
Public Types inherited from BPredUnit
typedef BranchPredictorParams	Params

Public Types inherited from SimObject
typedef SimObjectParams	Params

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)
	Serializes all the SimObjects. More...

static void	unserializeGlobals (CheckpointIn &cp)

Detailed Description

Definition at line 60 of file ltage.hh.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

protected

Enumerator
LOOP
LAST_LTAGE_PROVIDER_TYPE

Definition at line 79 of file ltage.hh.

Constructor & Destructor Documentation

◆ LTAGE()

LTAGE::LTAGE ( const LTAGEParams * params )

Definition at line 47 of file ltage.cc.

Member Function Documentation

◆ init()

void LTAGE::init ( )

overridevirtual

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

Initializations that are independent of unserialization but rely on a fully instantiated and connected SimObject graph should be done here.

Reimplemented from SimObject.

Definition at line 53 of file ltage.cc.

References SimObject::init().

◆ predict()

bool LTAGE::predict	(	ThreadID	tid,
		Addr	branch_pc,
		bool	cond_branch,
		void *&	b
	)

overrideprotectedvirtual

Get a branch prediction from LTAGE.

NOT an override of BpredUnit::predict().

Parameters

tid	The thread ID to select the global histories to use.
branch_pc	The unshifted branch PC.
cond_branch	True if the branch is conditional.
b	Reference to wrapping pointer to allow storing derived class prediction information in the base class.

Reimplemented from TAGE.

Reimplemented in TAGE_SC_L.

Definition at line 60 of file ltage.cc.

References ArmISA::b, PowerISA::bi, DPRINTF, LoopPredictor::getLoopUseCounter(), BPredUnit::instShiftAmt, LOOP, LoopPredictor::loopPredict(), loopPredictor, TAGE::tage, and TAGEBase::tagePredict().

◆ regStats()

void LTAGE::regStats ( )

overridevirtual

Callback to set stat parameters.

This callback is typically used for complex stats (e.g., distributions) that need parameters in addition to a name and a description. Stat names and descriptions should typically be set from the constructor usingo from the constructor using the ADD_STAT macro.

Reimplemented from Stats::Group.

Reimplemented in TAGE_SC_L.

Definition at line 145 of file ltage.cc.

References Stats::Group::regStats().

Referenced by TAGE_SC_L::regStats().

◆ squash()

void LTAGE::squash	(	ThreadID	tid,
		void *	bp_history
	)

overridevirtual

Parameters

bp_history Pointer to the history object. The predictor will need to update any state and delete the object.

Reimplemented from TAGE.

Definition at line 133 of file ltage.cc.

References PowerISA::bi, loopPredictor, TAGE::squash(), and LoopPredictor::squash().

◆ update()

void LTAGE::update	(	ThreadID	tid,
		Addr	instPC,
		bool	taken,
		void *	bp_history,
		bool	squashed,
		const StaticInstPtr &	inst,
		Addr	corrTarget
	)

overridevirtual

Updates the BP with taken/not taken information.

Parameters

inst_PC	The branch's PC that will be updated.
taken	Whether the branch was taken or not taken.
bp_history	Pointer to the branch predictor state that is associated with the branch lookup that is being updated.
squashed	Set to true when this function is called during a squash operation.
inst	Static instruction information
corrTarget	The resolved target of the branch (only needed for squashed branches)

Todo:: Make this update flexible enough to handle a global predictor.

Implements BPredUnit.

Reimplemented in TAGE_SC_L.

Definition at line 91 of file ltage.cc.

References PowerISA::bi, LoopPredictor::condBranchUpdate(), TAGEBase::condBranchUpdate(), DPRINTF, BPredUnit::instShiftAmt, TAGEBase::isSpeculativeUpdateEnabled(), loopPredictor, Random::random(), random_mt, TAGEBase::squash(), LoopPredictor::squashLoop(), TAGE::tage, TAGEBase::updateHistories(), LoopPredictor::updateStats(), and TAGEBase::updateStats().

Member Data Documentation

◆ loopPredictor

LoopPredictor* LTAGE::loopPredictor

protected

The loop predictor object.

Definition at line 76 of file ltage.hh.

Referenced by predict(), TAGE_SC_L::predict(), squash(), update(), and TAGE_SC_L::update().

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

cpu/pred/ltage.hh
cpu/pred/ltage.cc

Classes

Public Member Functions

Protected Types

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ LTAGE()

Member Function Documentation

◆ init()

◆ predict()

◆ regStats()

◆ squash()

◆ update()

Member Data Documentation

◆ loopPredictor