DefaultDecode class handles both single threaded and SMT decode. More...

#include <decode.hh>

Classes
struct	Stalls
	Source of possible stalls. More...

Public Types
enum	DecodeStatus { Active, Inactive }
	Overall decode stage status. More...

enum	ThreadStatus { Running, Idle, StartSquash, Squashing, Blocked, Unblocking }
	Individual thread status. More...

Public Member Functions
	DefaultDecode (O3CPU _cpu, DerivO3CPUParams params)
	DefaultDecode constructor. More...

void	startupStage ()

void	clearStates (ThreadID tid)
	Clear all thread-specific states. More...

void	resetStage ()

std::string	name () const
	Returns the name of decode. More...

void	regStats ()
	Registers statistics. More...

void	setTimeBuffer (TimeBuffer< TimeStruct > *tb_ptr)
	Sets the main backwards communication time buffer pointer. More...

void	setDecodeQueue (TimeBuffer< DecodeStruct > *dq_ptr)
	Sets pointer to time buffer used to communicate to the next stage. More...

void	setFetchQueue (TimeBuffer< FetchStruct > *fq_ptr)
	Sets pointer to time buffer coming from fetch. More...

void	setActiveThreads (std::list< ThreadID > *at_ptr)
	Sets pointer to list of active threads. More...

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

bool	isDrained () const
	Has the stage drained? More...

void	takeOverFrom ()
	Takes over from another CPU's thread. More...

void	tick ()
	Ticks decode, processing all input signals and decoding as many instructions as possible. More...

void	decode (bool &status_change, ThreadID tid)
	Determines what to do based on decode's current status. More...

void	decodeInsts (ThreadID tid)
	Processes instructions from fetch and passes them on to rename. More...

unsigned	squash (ThreadID tid)
	Squashes due to commit signalling a squash. More...

Private Types
typedef Impl::O3CPU	O3CPU

typedef Impl::DynInstPtr	DynInstPtr

typedef Impl::CPUPol	CPUPol

typedef CPUPol::FetchStruct	FetchStruct

typedef CPUPol::DecodeStruct	DecodeStruct

typedef CPUPol::TimeStruct	TimeStruct

Private Member Functions
void	skidInsert (ThreadID tid)
	Inserts a thread's instructions into the skid buffer, to be decoded once decode unblocks. More...

bool	skidsEmpty ()
	Returns if all of the skid buffers are empty. More...

void	updateStatus ()
	Updates overall decode status based on all of the threads' statuses. More...

void	sortInsts ()
	Separates instructions from fetch into individual lists of instructions sorted by thread. More...

void	readStallSignals (ThreadID tid)
	Reads all stall signals from the backwards communication timebuffer. More...

bool	checkSignalsAndUpdate (ThreadID tid)
	Checks all input signals and updates decode's status appropriately. More...

bool	checkStall (ThreadID tid) const
	Checks all stall signals, and returns if any are true. More...

bool	fetchInstsValid ()
	Returns if there any instructions from fetch on this cycle. More...

bool	block (ThreadID tid)
	Switches decode to blocking, and signals back that decode has become blocked. More...

bool	unblock (ThreadID tid)
	Switches decode to unblocking if the skid buffer is empty, and signals back that decode has unblocked. More...

void	squash (const DynInstPtr &inst, ThreadID tid)
	Squashes if there is a PC-relative branch that was predicted incorrectly. More...

Private Attributes
DecodeStatus	_status
	Decode status. More...

ThreadStatus	decodeStatus [Impl::MaxThreads]
	Per-thread status. More...

O3CPU *	cpu
	CPU interface. More...

TimeBuffer< TimeStruct > *	timeBuffer
	Time buffer interface. More...

TimeBuffer< TimeStruct >::wire	fromRename
	Wire to get rename's output from backwards time buffer. More...

TimeBuffer< TimeStruct >::wire	fromIEW
	Wire to get iew's information from backwards time buffer. More...

TimeBuffer< TimeStruct >::wire	fromCommit
	Wire to get commit's information from backwards time buffer. More...

TimeBuffer< TimeStruct >::wire	toFetch
	Wire to write information heading to previous stages. More...

TimeBuffer< DecodeStruct > *	decodeQueue
	Decode instruction queue. More...

TimeBuffer< DecodeStruct >::wire	toRename
	Wire used to write any information heading to rename. More...

TimeBuffer< FetchStruct > *	fetchQueue
	Fetch instruction queue interface. More...

TimeBuffer< FetchStruct >::wire	fromFetch
	Wire to get fetch's output from fetch queue. More...

std::queue< DynInstPtr >	insts [Impl::MaxThreads]
	Queue of all instructions coming from fetch this cycle. More...

std::queue< DynInstPtr >	skidBuffer [Impl::MaxThreads]
	Skid buffer between fetch and decode. More...

bool	wroteToTimeBuffer
	Variable that tracks if decode has written to the time buffer this cycle. More...

Stalls	stalls [Impl::MaxThreads]
	Tracks which stages are telling decode to stall. More...

Cycles	renameToDecodeDelay
	Rename to decode delay. More...

Cycles	iewToDecodeDelay
	IEW to decode delay. More...

Cycles	commitToDecodeDelay
	Commit to decode delay. More...

Cycles	fetchToDecodeDelay
	Fetch to decode delay. More...

unsigned	decodeWidth
	The width of decode, in instructions. More...

unsigned	toRenameIndex
	Index of instructions being sent to rename. More...

ThreadID	numThreads
	number of Active Threads More...

std::list< ThreadID > *	activeThreads
	List of active thread ids. More...

unsigned	skidBufferMax
	Maximum size of the skid buffer. More...

Addr	bdelayDoneSeqNum [Impl::MaxThreads]
	SeqNum of Squashing Branch Delay Instruction (used for MIPS) More...

DynInstPtr	squashInst [Impl::MaxThreads]
	Instruction used for squashing branch (used for MIPS) More...

bool	squashAfterDelaySlot [Impl::MaxThreads]
	Tells when their is a pending delay slot inst. More...

Stats::Scalar	decodeIdleCycles
	Stat for total number of idle cycles. More...

Stats::Scalar	decodeBlockedCycles
	Stat for total number of blocked cycles. More...

Stats::Scalar	decodeRunCycles
	Stat for total number of normal running cycles. More...

Stats::Scalar	decodeUnblockCycles
	Stat for total number of unblocking cycles. More...

Stats::Scalar	decodeSquashCycles
	Stat for total number of squashing cycles. More...

Stats::Scalar	decodeBranchResolved
	Stat for number of times a branch is resolved at decode. More...

Stats::Scalar	decodeBranchMispred
	Stat for number of times a branch mispredict is detected. More...

Stats::Scalar	decodeControlMispred
	Stat for number of times decode detected a non-control instruction incorrectly predicted as a branch. More...

Stats::Scalar	decodeDecodedInsts
	Stat for total number of decoded instructions. More...

Stats::Scalar	decodeSquashedInsts
	Stat for total number of squashed instructions. More...

Detailed Description

template<class Impl>
class DefaultDecode< Impl >

DefaultDecode class handles both single threaded and SMT decode.

Its width is specified by the parameters; each cycles it tries to decode that many instructions. Because instructions are actually decoded when the StaticInst is created, this stage does not do much other than check any PC-relative branches.

Definition at line 61 of file decode.hh.

Member Typedef Documentation

◆ CPUPol

template<class Impl >

typedef Impl::CPUPol DefaultDecode< Impl >::CPUPol

private

Definition at line 67 of file decode.hh.

◆ DecodeStruct

template<class Impl >

typedef CPUPol::DecodeStruct DefaultDecode< Impl >::DecodeStruct

private

Definition at line 71 of file decode.hh.

◆ DynInstPtr

template<class Impl >

typedef Impl::DynInstPtr DefaultDecode< Impl >::DynInstPtr

private

Definition at line 66 of file decode.hh.

◆ FetchStruct

template<class Impl >

typedef CPUPol::FetchStruct DefaultDecode< Impl >::FetchStruct

private

Definition at line 70 of file decode.hh.

◆ O3CPU

template<class Impl >

typedef Impl::O3CPU DefaultDecode< Impl >::O3CPU

private

Definition at line 65 of file decode.hh.

◆ TimeStruct

template<class Impl >

typedef CPUPol::TimeStruct DefaultDecode< Impl >::TimeStruct

private

Definition at line 72 of file decode.hh.

Member Enumeration Documentation

◆ DecodeStatus

template<class Impl >

enum DefaultDecode::DecodeStatus

Overall decode stage status.

Used to determine if the CPU can deschedule itself due to a lack of activity.

Enumerator
Active
Inactive

Definition at line 78 of file decode.hh.

◆ ThreadStatus

template<class Impl >

enum DefaultDecode::ThreadStatus

Individual thread status.

Enumerator
Running
Idle
StartSquash
Squashing
Blocked
Unblocking

Definition at line 84 of file decode.hh.

Constructor & Destructor Documentation

◆ DefaultDecode()

template<class Impl >

DefaultDecode< Impl >::DefaultDecode	(	O3CPU *	_cpu,
		DerivO3CPUParams *	params
	)

DefaultDecode constructor.

Definition at line 62 of file decode_impl.hh.

References DefaultDecode< Impl >::bdelayDoneSeqNum, DefaultDecode< Impl >::decodeStatus, DefaultDecode< Impl >::decodeWidth, fatal, DefaultDecode< Impl >::fetchToDecodeDelay, DefaultDecode< Impl >::Idle, DefaultDecode< Impl >::skidBufferMax, DefaultDecode< Impl >::squashAfterDelaySlot, DefaultDecode< Impl >::squashInst, and DefaultDecode< Impl >::stalls.

Member Function Documentation

◆ block()

template<class Impl >

bool DefaultDecode< Impl >::block ( ThreadID tid )

private

Switches decode to blocking, and signals back that decode has become blocked.

Returns: Returns true if there is a status change.

Definition at line 257 of file decode_impl.hh.

References DefaultDecode< Impl >::Blocked, DefaultDecode< Impl >::decodeStatus, DPRINTF, DefaultDecode< Impl >::skidInsert(), DefaultDecode< Impl >::toFetch, and DefaultDecode< Impl >::wroteToTimeBuffer.

Referenced by DefaultDecode< Impl >::checkSignalsAndUpdate(), DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::takeOverFrom().

◆ checkSignalsAndUpdate()

template<class Impl >

bool DefaultDecode< Impl >::checkSignalsAndUpdate ( ThreadID tid )

private

Checks all input signals and updates decode's status appropriately.

Definition at line 509 of file decode_impl.hh.

References DefaultDecode< Impl >::block(), DefaultDecode< Impl >::Blocked, DefaultDecode< Impl >::checkStall(), DefaultDecode< Impl >::decodeStatus, DPRINTF, DefaultDecode< Impl >::fromCommit, DefaultDecode< Impl >::readStallSignals(), DefaultDecode< Impl >::Running, DefaultDecode< Impl >::squash(), DefaultDecode< Impl >::Squashing, DefaultDecode< Impl >::unblock(), and DefaultDecode< Impl >::Unblocking.

Referenced by DefaultDecode< Impl >::takeOverFrom(), and DefaultDecode< Impl >::tick().

◆ checkStall()

template<class Impl >

bool DefaultDecode< Impl >::checkStall ( ThreadID tid ) const

private

Checks all stall signals, and returns if any are true.

Definition at line 236 of file decode_impl.hh.

References DPRINTF, and DefaultDecode< Impl >::stalls.

Referenced by DefaultDecode< Impl >::checkSignalsAndUpdate(), and DefaultDecode< Impl >::takeOverFrom().

◆ clearStates()

template<class Impl >

void DefaultDecode< Impl >::clearStates ( ThreadID tid )

Clear all thread-specific states.

Definition at line 96 of file decode_impl.hh.

References DefaultDecode< Impl >::decodeStatus, DefaultDecode< Impl >::Idle, DefaultDecode< Impl >::Stalls::rename, and DefaultDecode< Impl >::stalls.

◆ decode()

template<class Impl >

void DefaultDecode< Impl >::decode	(	bool &	status_change,
		ThreadID	tid
	)

Determines what to do based on decode's current status.

Parameters

status_change	decode() sets this variable if there was a status change (ie switching from from blocking to unblocking).
tid	Thread id to decode instructions from.

Definition at line 602 of file decode_impl.hh.

References DefaultDecode< Impl >::Blocked, DefaultDecode< Impl >::decodeBlockedCycles, DefaultDecode< Impl >::decodeInsts(), DefaultDecode< Impl >::decodeSquashCycles, DefaultDecode< Impl >::decodeStatus, DPRINTF, DefaultDecode< Impl >::fetchInstsValid(), DefaultDecode< Impl >::Idle, DefaultDecode< Impl >::Running, DefaultDecode< Impl >::skidInsert(), DefaultDecode< Impl >::skidsEmpty(), DefaultDecode< Impl >::Squashing, DefaultDecode< Impl >::unblock(), and DefaultDecode< Impl >::Unblocking.

Referenced by DefaultDecode< Impl >::takeOverFrom(), and DefaultDecode< Impl >::tick().

◆ decodeInsts()

template<class Impl >

void DefaultDecode< Impl >::decodeInsts ( ThreadID tid )

Processes instructions from fetch and passes them on to rename.

Decoding of instructions actually happens when they are created in fetch, so this function mostly checks if PC-relative branches are correct.

Definition at line 647 of file decode_impl.hh.

Referenced by DefaultDecode< Impl >::decode(), and DefaultDecode< Impl >::takeOverFrom().

◆ drainSanityCheck()

template<class Impl >

void DefaultDecode< Impl >::drainSanityCheck ( ) const

Perform sanity checks after a drain.

Definition at line 214 of file decode_impl.hh.

References DefaultDecode< Impl >::insts, DefaultDecode< Impl >::numThreads, and DefaultDecode< Impl >::skidBuffer.

◆ fetchInstsValid()

template<class Impl >

bool DefaultDecode< Impl >::fetchInstsValid ( )

inlineprivate

Returns if there any instructions from fetch on this cycle.

Definition at line 250 of file decode_impl.hh.

References DefaultDecode< Impl >::fromFetch, and TimeBuffer< T >::size.

Referenced by DefaultDecode< Impl >::decode(), and DefaultDecode< Impl >::takeOverFrom().

◆ isDrained()

template<class Impl >

bool DefaultDecode< Impl >::isDrained ( ) const

Has the stage drained?

Definition at line 224 of file decode_impl.hh.

References DefaultDecode< Impl >::decodeStatus, DefaultDecode< Impl >::Idle, DefaultDecode< Impl >::insts, DefaultDecode< Impl >::numThreads, DefaultDecode< Impl >::Running, and DefaultDecode< Impl >::skidBuffer.

◆ name()

template<class Impl >

std::string DefaultDecode< Impl >::name ( ) const

Returns the name of decode.

Definition at line 118 of file decode_impl.hh.

References DefaultDecode< Impl >::cpu.

Referenced by DefaultDecode< Impl >::regStats().

◆ readStallSignals()

template<class Impl >

void DefaultDecode< Impl >::readStallSignals ( ThreadID tid )

private

Reads all stall signals from the backwards communication timebuffer.

Definition at line 495 of file decode_impl.hh.

References DefaultDecode< Impl >::fromRename, DefaultDecode< Impl >::Stalls::rename, and DefaultDecode< Impl >::stalls.

Referenced by DefaultDecode< Impl >::checkSignalsAndUpdate(), and DefaultDecode< Impl >::takeOverFrom().

◆ regStats()

template<class Impl >

void DefaultDecode< Impl >::regStats ( )

Registers statistics.

Definition at line 125 of file decode_impl.hh.

◆ resetStage()

template<class Impl >

void DefaultDecode< Impl >::resetStage ( )

Definition at line 104 of file decode_impl.hh.

References DefaultDecode< Impl >::_status, DefaultDecode< Impl >::decodeStatus, DefaultDecode< Impl >::Idle, DefaultDecode< Impl >::Inactive, DefaultDecode< Impl >::numThreads, DefaultDecode< Impl >::Stalls::rename, and DefaultDecode< Impl >::stalls.

Referenced by DefaultDecode< Impl >::startupStage(), and DefaultDecode< Impl >::takeOverFrom().

◆ setActiveThreads()

template<class Impl >

void DefaultDecode< Impl >::setActiveThreads ( std::list< ThreadID > * at_ptr )

Sets pointer to list of active threads.

Definition at line 207 of file decode_impl.hh.

References DefaultDecode< Impl >::activeThreads.

◆ setDecodeQueue()

template<class Impl >

void DefaultDecode< Impl >::setDecodeQueue ( TimeBuffer< DecodeStruct > * dq_ptr )

Sets pointer to time buffer used to communicate to the next stage.

Definition at line 187 of file decode_impl.hh.

References DefaultDecode< Impl >::decodeQueue, TimeBuffer< T >::getWire(), and DefaultDecode< Impl >::toRename.

◆ setFetchQueue()

template<class Impl >

void DefaultDecode< Impl >::setFetchQueue ( TimeBuffer< FetchStruct > * fq_ptr )

Sets pointer to time buffer coming from fetch.

Definition at line 197 of file decode_impl.hh.

References DefaultDecode< Impl >::fetchQueue, DefaultDecode< Impl >::fetchToDecodeDelay, DefaultDecode< Impl >::fromFetch, and TimeBuffer< T >::getWire().

◆ setTimeBuffer()

template<class Impl >

void DefaultDecode< Impl >::setTimeBuffer ( TimeBuffer< TimeStruct > * tb_ptr )

Sets the main backwards communication time buffer pointer.

Definition at line 172 of file decode_impl.hh.

References DefaultDecode< Impl >::commitToDecodeDelay, DefaultDecode< Impl >::fromCommit, DefaultDecode< Impl >::fromIEW, DefaultDecode< Impl >::fromRename, TimeBuffer< T >::getWire(), DefaultDecode< Impl >::iewToDecodeDelay, DefaultDecode< Impl >::renameToDecodeDelay, DefaultDecode< Impl >::timeBuffer, and DefaultDecode< Impl >::toFetch.

◆ skidInsert()

template<class Impl >

void DefaultDecode< Impl >::skidInsert ( ThreadID tid )

private

Inserts a thread's instructions into the skid buffer, to be decoded once decode unblocks.

Definition at line 406 of file decode_impl.hh.

References DPRINTF, DefaultDecode< Impl >::insts, DefaultDecode< Impl >::skidBuffer, and DefaultDecode< Impl >::skidBufferMax.

Referenced by DefaultDecode< Impl >::block(), DefaultDecode< Impl >::decode(), and DefaultDecode< Impl >::takeOverFrom().

◆ skidsEmpty()

template<class Impl >

bool DefaultDecode< Impl >::skidsEmpty ( )

private

Returns if all of the skid buffers are empty.

Definition at line 430 of file decode_impl.hh.

References DefaultDecode< Impl >::activeThreads, and DefaultDecode< Impl >::skidBuffer.

Referenced by DefaultDecode< Impl >::decode(), and DefaultDecode< Impl >::takeOverFrom().

◆ sortInsts()

template<class Impl >

void DefaultDecode< Impl >::sortInsts ( )

private

Separates instructions from fetch into individual lists of instructions sorted by thread.

Definition at line 485 of file decode_impl.hh.

References DefaultDecode< Impl >::fromFetch, ArmISA::i, DefaultDecode< Impl >::insts, and TimeBuffer< T >::size.

Referenced by DefaultDecode< Impl >::takeOverFrom(), and DefaultDecode< Impl >::tick().

◆ squash() [1/2]

template<class Impl >

void DefaultDecode< Impl >::squash	(	const DynInstPtr &	inst,
		ThreadID	tid
	)

private

Squashes if there is a PC-relative branch that was predicted incorrectly.

Sends squash information back to fetch.

Definition at line 306 of file decode_impl.hh.

References DefaultDecode< Impl >::Blocked, DefaultDecode< Impl >::cpu, DefaultDecode< Impl >::decodeStatus, DPRINTF, DefaultDecode< Impl >::fromFetch, ArmISA::i, DefaultDecode< Impl >::insts, TimeBuffer< T >::size, DefaultDecode< Impl >::skidBuffer, DefaultDecode< Impl >::Squashing, DefaultDecode< Impl >::toFetch, and DefaultDecode< Impl >::Unblocking.

Referenced by DefaultDecode< Impl >::checkSignalsAndUpdate(), DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::takeOverFrom().

◆ squash() [2/2]

template<class Impl >

unsigned DefaultDecode< Impl >::squash ( ThreadID tid )

Squashes due to commit signalling a squash.

Changes status to squashing and clears block/unblock signals as needed.

Definition at line 358 of file decode_impl.hh.

References DefaultDecode< Impl >::Blocked, DefaultDecode< Impl >::decodeStatus, DPRINTF, DefaultDecode< Impl >::fromFetch, FullSystem, ArmISA::i, DefaultDecode< Impl >::insts, TimeBuffer< T >::size, DefaultDecode< Impl >::skidBuffer, DefaultDecode< Impl >::Squashing, DefaultDecode< Impl >::toFetch, and DefaultDecode< Impl >::Unblocking.

◆ startupStage()

template<class Impl >

void DefaultDecode< Impl >::startupStage ( )

Definition at line 89 of file decode_impl.hh.

References DefaultDecode< Impl >::resetStage().

◆ takeOverFrom()

template<class Impl >

void DefaultDecode< Impl >::takeOverFrom ( )

inline

Takes over from another CPU's thread.

Definition at line 136 of file decode.hh.

◆ tick()

template<class Impl >

void DefaultDecode< Impl >::tick ( )

Ticks decode, processing all input signals and decoding as many instructions as possible.

Definition at line 566 of file decode_impl.hh.

References DefaultDecode< Impl >::activeThreads, DefaultDecode< Impl >::checkSignalsAndUpdate(), DefaultDecode< Impl >::cpu, DefaultDecode< Impl >::decode(), DPRINTF, DefaultDecode< Impl >::sortInsts(), DefaultDecode< Impl >::toRenameIndex, DefaultDecode< Impl >::updateStatus(), and DefaultDecode< Impl >::wroteToTimeBuffer.

Referenced by DefaultDecode< Impl >::takeOverFrom().

◆ unblock()

template<class Impl >

bool DefaultDecode< Impl >::unblock ( ThreadID tid )

private

Switches decode to unblocking if the skid buffer is empty, and signals back that decode has unblocked.

Returns: Returns true if there is a status change.

Definition at line 287 of file decode_impl.hh.

References DefaultDecode< Impl >::decodeStatus, DPRINTF, DefaultDecode< Impl >::Running, DefaultDecode< Impl >::skidBuffer, DefaultDecode< Impl >::toFetch, and DefaultDecode< Impl >::wroteToTimeBuffer.

Referenced by DefaultDecode< Impl >::checkSignalsAndUpdate(), DefaultDecode< Impl >::decode(), and DefaultDecode< Impl >::takeOverFrom().

◆ updateStatus()

template<class Impl >

void DefaultDecode< Impl >::updateStatus ( )

private

Updates overall decode status based on all of the threads' statuses.

Definition at line 446 of file decode_impl.hh.

References DefaultDecode< Impl >::_status, DefaultDecode< Impl >::Active, DefaultDecode< Impl >::activeThreads, DefaultDecode< Impl >::cpu, DefaultDecode< Impl >::decodeStatus, DPRINTF, DefaultDecode< Impl >::Inactive, and DefaultDecode< Impl >::Unblocking.

Referenced by DefaultDecode< Impl >::takeOverFrom(), and DefaultDecode< Impl >::tick().

Member Data Documentation

◆ _status

template<class Impl >

DecodeStatus DefaultDecode< Impl >::_status

private

Decode status.

Definition at line 95 of file decode.hh.

Referenced by DefaultDecode< Impl >::resetStage(), and DefaultDecode< Impl >::updateStatus().

◆ activeThreads

template<class Impl >

std::list<ThreadID>* DefaultDecode< Impl >::activeThreads

private

List of active thread ids.

Definition at line 283 of file decode.hh.

Referenced by DefaultDecode< Impl >::setActiveThreads(), DefaultDecode< Impl >::skidsEmpty(), DefaultDecode< Impl >::tick(), and DefaultDecode< Impl >::updateStatus().

◆ bdelayDoneSeqNum

template<class Impl >

Addr DefaultDecode< Impl >::bdelayDoneSeqNum[Impl::MaxThreads]

private

SeqNum of Squashing Branch Delay Instruction (used for MIPS)

Definition at line 289 of file decode.hh.

Referenced by DefaultDecode< Impl >::DefaultDecode().

◆ commitToDecodeDelay

template<class Impl >

Cycles DefaultDecode< Impl >::commitToDecodeDelay

private

Commit to decode delay.

Definition at line 268 of file decode.hh.

Referenced by DefaultDecode< Impl >::setTimeBuffer().

◆ cpu

template<class Impl >

O3CPU* DefaultDecode< Impl >::cpu

private

CPU interface.

Definition at line 212 of file decode.hh.

Referenced by DefaultDecode< Impl >::name(), DefaultDecode< Impl >::squash(), DefaultDecode< Impl >::tick(), and DefaultDecode< Impl >::updateStatus().

◆ decodeBlockedCycles

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeBlockedCycles

private

Stat for total number of blocked cycles.

Definition at line 304 of file decode.hh.

Referenced by DefaultDecode< Impl >::decode(), and DefaultDecode< Impl >::regStats().

◆ decodeBranchMispred

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeBranchMispred

private

Stat for number of times a branch mispredict is detected.

Definition at line 314 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeBranchResolved

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeBranchResolved

private

Stat for number of times a branch is resolved at decode.

Definition at line 312 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeControlMispred

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeControlMispred

private

Stat for number of times decode detected a non-control instruction incorrectly predicted as a branch.

Definition at line 318 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeDecodedInsts

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeDecodedInsts

private

Stat for total number of decoded instructions.

Definition at line 320 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeIdleCycles

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeIdleCycles

private

Stat for total number of idle cycles.

Definition at line 302 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeQueue

template<class Impl >

TimeBuffer<DecodeStruct>* DefaultDecode< Impl >::decodeQueue

private

Decode instruction queue.

Definition at line 231 of file decode.hh.

Referenced by DefaultDecode< Impl >::setDecodeQueue().

◆ decodeRunCycles

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeRunCycles

private

Stat for total number of normal running cycles.

Definition at line 306 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeSquashCycles

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeSquashCycles

private

Stat for total number of squashing cycles.

Definition at line 310 of file decode.hh.

Referenced by DefaultDecode< Impl >::decode(), and DefaultDecode< Impl >::regStats().

◆ decodeSquashedInsts

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeSquashedInsts

private

Stat for total number of squashed instructions.

Definition at line 322 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeStatus

template<class Impl >

ThreadStatus DefaultDecode< Impl >::decodeStatus[Impl::MaxThreads]

private

Per-thread status.

Definition at line 98 of file decode.hh.

Referenced by DefaultDecode< Impl >::block(), DefaultDecode< Impl >::checkSignalsAndUpdate(), DefaultDecode< Impl >::clearStates(), DefaultDecode< Impl >::decode(), DefaultDecode< Impl >::decodeInsts(), DefaultDecode< Impl >::DefaultDecode(), DefaultDecode< Impl >::isDrained(), DefaultDecode< Impl >::resetStage(), DefaultDecode< Impl >::squash(), DefaultDecode< Impl >::unblock(), and DefaultDecode< Impl >::updateStatus().

◆ decodeUnblockCycles

template<class Impl >

Stats::Scalar DefaultDecode< Impl >::decodeUnblockCycles

private

Stat for total number of unblocking cycles.

Definition at line 308 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::regStats().

◆ decodeWidth

template<class Impl >

unsigned DefaultDecode< Impl >::decodeWidth

private

The width of decode, in instructions.

Definition at line 274 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::DefaultDecode().

◆ fetchQueue

template<class Impl >

TimeBuffer<FetchStruct>* DefaultDecode< Impl >::fetchQueue

private

Fetch instruction queue interface.

Definition at line 237 of file decode.hh.

Referenced by DefaultDecode< Impl >::setFetchQueue().

◆ fetchToDecodeDelay

template<class Impl >

Cycles DefaultDecode< Impl >::fetchToDecodeDelay

private

Fetch to decode delay.

Definition at line 271 of file decode.hh.

Referenced by DefaultDecode< Impl >::DefaultDecode(), and DefaultDecode< Impl >::setFetchQueue().

◆ fromCommit

template<class Impl >

TimeBuffer<TimeStruct>::wire DefaultDecode< Impl >::fromCommit

private

Wire to get commit's information from backwards time buffer.

Definition at line 224 of file decode.hh.

Referenced by DefaultDecode< Impl >::checkSignalsAndUpdate(), and DefaultDecode< Impl >::setTimeBuffer().

◆ fromFetch

template<class Impl >

TimeBuffer<FetchStruct>::wire DefaultDecode< Impl >::fromFetch

private

Wire to get fetch's output from fetch queue.

Definition at line 240 of file decode.hh.

Referenced by DefaultDecode< Impl >::fetchInstsValid(), DefaultDecode< Impl >::setFetchQueue(), DefaultDecode< Impl >::sortInsts(), and DefaultDecode< Impl >::squash().

◆ fromIEW

template<class Impl >

TimeBuffer<TimeStruct>::wire DefaultDecode< Impl >::fromIEW

private

Wire to get iew's information from backwards time buffer.

Definition at line 221 of file decode.hh.

Referenced by DefaultDecode< Impl >::setTimeBuffer().

◆ fromRename

template<class Impl >

TimeBuffer<TimeStruct>::wire DefaultDecode< Impl >::fromRename

private

Wire to get rename's output from backwards time buffer.

Definition at line 218 of file decode.hh.

Referenced by DefaultDecode< Impl >::readStallSignals(), and DefaultDecode< Impl >::setTimeBuffer().

◆ iewToDecodeDelay

template<class Impl >

Cycles DefaultDecode< Impl >::iewToDecodeDelay

private

IEW to decode delay.

Definition at line 265 of file decode.hh.

Referenced by DefaultDecode< Impl >::setTimeBuffer().

◆ insts

template<class Impl >

std::queue<DynInstPtr> DefaultDecode< Impl >::insts[Impl::MaxThreads]

private

Queue of all instructions coming from fetch this cycle.

Definition at line 243 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), DefaultDecode< Impl >::drainSanityCheck(), DefaultDecode< Impl >::isDrained(), DefaultDecode< Impl >::skidInsert(), DefaultDecode< Impl >::sortInsts(), and DefaultDecode< Impl >::squash().

◆ numThreads

template<class Impl >

ThreadID DefaultDecode< Impl >::numThreads

private

number of Active Threads

Definition at line 280 of file decode.hh.

Referenced by DefaultDecode< Impl >::drainSanityCheck(), DefaultDecode< Impl >::isDrained(), and DefaultDecode< Impl >::resetStage().

◆ renameToDecodeDelay

template<class Impl >

Cycles DefaultDecode< Impl >::renameToDecodeDelay

private

Rename to decode delay.

Definition at line 262 of file decode.hh.

Referenced by DefaultDecode< Impl >::setTimeBuffer().

◆ skidBuffer

template<class Impl >

std::queue<DynInstPtr> DefaultDecode< Impl >::skidBuffer[Impl::MaxThreads]

private

Skid buffer between fetch and decode.

Definition at line 246 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), DefaultDecode< Impl >::drainSanityCheck(), DefaultDecode< Impl >::isDrained(), DefaultDecode< Impl >::skidInsert(), DefaultDecode< Impl >::skidsEmpty(), DefaultDecode< Impl >::squash(), and DefaultDecode< Impl >::unblock().

◆ skidBufferMax

template<class Impl >

unsigned DefaultDecode< Impl >::skidBufferMax

private

Maximum size of the skid buffer.

Definition at line 286 of file decode.hh.

Referenced by DefaultDecode< Impl >::DefaultDecode(), and DefaultDecode< Impl >::skidInsert().

◆ squashAfterDelaySlot

template<class Impl >

bool DefaultDecode< Impl >::squashAfterDelaySlot[Impl::MaxThreads]

private

Tells when their is a pending delay slot inst.

to send to rename. If there is, then wait squash after the next instruction (used for MIPS).

Definition at line 298 of file decode.hh.

Referenced by DefaultDecode< Impl >::DefaultDecode().

◆ squashInst

template<class Impl >

DynInstPtr DefaultDecode< Impl >::squashInst[Impl::MaxThreads]

private

Instruction used for squashing branch (used for MIPS)

Definition at line 292 of file decode.hh.

Referenced by DefaultDecode< Impl >::DefaultDecode().

◆ stalls

template<class Impl >

Stalls DefaultDecode< Impl >::stalls[Impl::MaxThreads]

private

Tracks which stages are telling decode to stall.

Definition at line 259 of file decode.hh.

Referenced by DefaultDecode< Impl >::checkStall(), DefaultDecode< Impl >::clearStates(), DefaultDecode< Impl >::DefaultDecode(), DefaultDecode< Impl >::readStallSignals(), and DefaultDecode< Impl >::resetStage().

◆ timeBuffer

template<class Impl >

TimeBuffer<TimeStruct>* DefaultDecode< Impl >::timeBuffer

private

Time buffer interface.

Definition at line 215 of file decode.hh.

Referenced by DefaultDecode< Impl >::setTimeBuffer().

◆ toFetch

template<class Impl >

TimeBuffer<TimeStruct>::wire DefaultDecode< Impl >::toFetch

private

Wire to write information heading to previous stages.

Definition at line 228 of file decode.hh.

Referenced by DefaultDecode< Impl >::block(), DefaultDecode< Impl >::setTimeBuffer(), DefaultDecode< Impl >::squash(), and DefaultDecode< Impl >::unblock().

◆ toRename

template<class Impl >

TimeBuffer<DecodeStruct>::wire DefaultDecode< Impl >::toRename

private

Wire used to write any information heading to rename.

Definition at line 234 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::setDecodeQueue().

◆ toRenameIndex

template<class Impl >

unsigned DefaultDecode< Impl >::toRenameIndex

private

Index of instructions being sent to rename.

Definition at line 277 of file decode.hh.

Referenced by DefaultDecode< Impl >::decodeInsts(), and DefaultDecode< Impl >::tick().

◆ wroteToTimeBuffer

template<class Impl >

bool DefaultDecode< Impl >::wroteToTimeBuffer

private

Variable that tracks if decode has written to the time buffer this cycle.

Used to tell CPU if there is activity this cycle.

Definition at line 251 of file decode.hh.

Referenced by DefaultDecode< Impl >::block(), DefaultDecode< Impl >::decodeInsts(), DefaultDecode< Impl >::tick(), and DefaultDecode< Impl >::unblock().

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

cpu/o3/decode.hh
cpu/o3/decode_impl.hh

Classes

Public Types

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

template<class Impl> class DefaultDecode< Impl >

Member Typedef Documentation

◆ CPUPol

◆ DecodeStruct

◆ DynInstPtr

◆ FetchStruct

◆ O3CPU

◆ TimeStruct

Member Enumeration Documentation

◆ DecodeStatus

◆ ThreadStatus

Constructor & Destructor Documentation

◆ DefaultDecode()

Member Function Documentation

◆ block()

◆ checkSignalsAndUpdate()

◆ checkStall()

◆ clearStates()

◆ decode()

◆ decodeInsts()

◆ drainSanityCheck()

◆ fetchInstsValid()

◆ isDrained()

◆ name()

◆ readStallSignals()

◆ regStats()

◆ resetStage()

◆ setActiveThreads()

◆ setDecodeQueue()

◆ setFetchQueue()

◆ setTimeBuffer()

◆ skidInsert()

◆ skidsEmpty()

◆ sortInsts()

◆ squash() [1/2]

◆ squash() [2/2]

◆ startupStage()

◆ takeOverFrom()

◆ tick()

◆ unblock()

◆ updateStatus()

Member Data Documentation

◆ _status

◆ activeThreads

◆ bdelayDoneSeqNum

◆ commitToDecodeDelay

◆ cpu

◆ decodeBlockedCycles

◆ decodeBranchMispred

◆ decodeBranchResolved

◆ decodeControlMispred

◆ decodeDecodedInsts

◆ decodeIdleCycles

◆ decodeQueue

◆ decodeRunCycles

◆ decodeSquashCycles

◆ decodeSquashedInsts

◆ decodeStatus

◆ decodeUnblockCycles

◆ decodeWidth

◆ fetchQueue

◆ fetchToDecodeDelay

◆ fromCommit

◆ fromFetch

◆ fromIEW

◆ fromRename

◆ iewToDecodeDelay

◆ insts

◆ numThreads

◆ renameToDecodeDelay

◆ skidBuffer

◆ skidBufferMax

◆ squashAfterDelaySlot

template<class Impl>
class DefaultDecode< Impl >