gem5  v21.2.0.0
Public Member Functions | Protected Attributes | List of all members
gem5::InstDecoder Class Referenceabstract

#include <decoder.hh>

Inheritance diagram for gem5::InstDecoder:
gem5::SimObject gem5::EventManager gem5::Serializable gem5::Drainable gem5::statistics::Group gem5::Named gem5::ArmISA::Decoder gem5::MipsISA::Decoder gem5::PowerISA::Decoder gem5::RiscvISA::Decoder gem5::SparcISA::Decoder gem5::X86ISA::Decoder

Public Member Functions

template<typename MoreBytesType >
 InstDecoder (const InstDecoderParams &params, MoreBytesType *mb_buf)
 
virtual StaticInstPtr fetchRomMicroop (MicroPC micropc, StaticInstPtr curMacroop)
 
virtual void reset ()
 
template<class Type >
Type & as ()
 
template<class Type >
const Type & as () const
 
virtual void takeOverFrom (InstDecoder *old)
 Take over the state from an old decoder when switching CPUs. More...
 
void * moreBytesPtr () const
 
size_t moreBytesSize () const
 
Addr pcMask () const
 
bool instReady () const
 Is an instruction ready to be decoded? More...
 
bool needMoreBytes () const
 Can the decoder accept more data? More...
 
virtual void moreBytes (const PCStateBase &pc, Addr fetchPC)=0
 Feed data to the decoder. More...
 
virtual StaticInstPtr decode (PCStateBase &pc)=0
 Decode an instruction or fetch it from the code cache. More...
 
- Public Member Functions inherited from gem5::SimObject
const Paramsparams () const
 
 SimObject (const Params &p)
 
virtual ~SimObject ()
 
virtual void init ()
 init() is called after all C++ SimObjects have been created and all ports are connected. More...
 
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...
 
ProbeManagergetProbeManager ()
 Get the probe manager for this object. More...
 
virtual PortgetPort (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 gem5::EventManager
EventQueueeventQueue () 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 gem5::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 gem5::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 gem5::statistics::Group
 Group (Group *parent, const char *name=nullptr)
 Construct a new statistics group. More...
 
virtual ~Group ()
 
virtual void regStats ()
 Callback to set stat parameters. More...
 
virtual void resetStats ()
 Callback to reset stats. More...
 
virtual void preDumpStats ()
 Callback before stats are dumped. More...
 
void addStat (statistics::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 InforesolveStat (std::string name) const
 Resolve a stat by its name within this group. More...
 
void mergeStatGroup (Group *block)
 Merge the contents (stats & children) of a block to this block. More...
 
 Group ()=delete
 
 Group (const Group &)=delete
 
Groupoperator= (const Group &)=delete
 
- Public Member Functions inherited from gem5::Named
 Named (const std::string &name_)
 
virtual ~Named ()=default
 
virtual std::string name () const
 

Protected Attributes

void * _moreBytesPtr
 
size_t _moreBytesSize
 
Addr _pcMask
 
bool instDone = false
 
bool outOfBytes = true
 
- Protected Attributes inherited from gem5::SimObject
const SimObjectParams & _params
 Cached copy of the object parameters. More...
 
- Protected Attributes inherited from gem5::EventManager
EventQueueeventq
 A pointer to this object's event queue. More...
 

Additional Inherited Members

- Public Types inherited from gem5::SimObject
typedef SimObjectParams Params
 
- Static Public Member Functions inherited from gem5::SimObject
static void serializeAll (const std::string &cpt_dir)
 Create a checkpoint by serializing all SimObjects in the system. More...
 
static SimObjectfind (const char *name)
 Find the SimObject with the given name and return a pointer to it. More...
 
static void setSimObjectResolver (SimObjectResolver *resolver)
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
static SimObjectResolvergetSimObjectResolver ()
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
- Static Public Member Functions inherited from gem5::Serializable
static const std::string & currentSection ()
 Gets the fully-qualified name of the active section. More...
 
static void generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
 Generate a checkpoint file so that the serialization can be routed to it. More...
 
- Protected Member Functions inherited from gem5::Drainable
 Drainable ()
 
virtual ~Drainable ()
 
virtual void drainResume ()
 Resume execution after a successful drain. More...
 
void signalDrainDone () const
 Signal that an object is drained. More...
 

Detailed Description

Definition at line 42 of file decoder.hh.

Constructor & Destructor Documentation

◆ InstDecoder()

template<typename MoreBytesType >
gem5::InstDecoder::InstDecoder ( const InstDecoderParams &  params,
MoreBytesType *  mb_buf 
)
inline

Definition at line 54 of file decoder.hh.

Member Function Documentation

◆ as() [1/2]

template<class Type >
Type& gem5::InstDecoder::as ( )
inline

◆ as() [2/2]

template<class Type >
const Type& gem5::InstDecoder::as ( ) const
inline

Definition at line 78 of file decoder.hh.

◆ decode()

virtual StaticInstPtr gem5::InstDecoder::decode ( PCStateBase pc)
pure virtual

Decode an instruction or fetch it from the code cache.

This method decodes the currently pending pre-decoded instruction. Data must be fed to the decoder using moreBytes() until instReady() is true before calling this method.

Parameters
pcInstruction pointer that we are decoding.
Returns
A pointer to a static instruction or NULL if the decoder isn't ready (see instReady()).

Implemented in gem5::ArmISA::Decoder, gem5::RiscvISA::Decoder, gem5::X86ISA::Decoder, gem5::SparcISA::Decoder, gem5::MipsISA::Decoder, and gem5::PowerISA::Decoder.

◆ fetchRomMicroop()

StaticInstPtr gem5::InstDecoder::fetchRomMicroop ( MicroPC  micropc,
StaticInstPtr  curMacroop 
)
virtual

Reimplemented in gem5::X86ISA::Decoder.

Definition at line 36 of file decoder.cc.

References panic.

◆ instReady()

bool gem5::InstDecoder::instReady ( ) const
inline

Is an instruction ready to be decoded?

CPU models call this method to determine if decode() will return a new instruction on the next call. It typically only returns false if the decoder hasn't received enough data to decode a full instruction.

Definition at line 107 of file decoder.hh.

References instDone.

◆ moreBytes()

virtual void gem5::InstDecoder::moreBytes ( const PCStateBase pc,
Addr  fetchPC 
)
pure virtual

Feed data to the decoder.

A CPU model uses this interface to load instruction data into the decoder. Once enough data has been loaded (check with instReady()), a decoded instruction can be retrieved using decode(PCStateBase &).

This method is intended to support both fixed-length and variable-length instructions. Instruction data is fetch in MachInst blocks (which correspond to the size of a typical insturction). The method might need to be called multiple times if the instruction spans multiple blocks, in that case needMoreBytes() will return true and instReady() will return false.

The fetchPC parameter is used to indicate where in memory the instruction was fetched from. This is should be the same address as the pc. If fetching multiple blocks, it indicates where subsequent blocks are fetched from (pc + n * sizeof(MachInst)).

Parameters
pcInstruction pointer that we are decoding.
fetchPCThe address this chunk was fetched from.

Implemented in gem5::X86ISA::Decoder, gem5::ArmISA::Decoder, gem5::RiscvISA::Decoder, gem5::MipsISA::Decoder, gem5::SparcISA::Decoder, and gem5::PowerISA::Decoder.

Referenced by gem5::o3::Fetch::fetch().

◆ moreBytesPtr()

void* gem5::InstDecoder::moreBytesPtr ( ) const
inline

Definition at line 95 of file decoder.hh.

References _moreBytesPtr.

◆ moreBytesSize()

size_t gem5::InstDecoder::moreBytesSize ( ) const
inline

Definition at line 96 of file decoder.hh.

References _moreBytesSize.

Referenced by gem5::o3::Fetch::Fetch().

◆ needMoreBytes()

bool gem5::InstDecoder::needMoreBytes ( ) const
inline

Can the decoder accept more data?

A CPU model uses this method to determine if the decoder can accept more data. Note that an instruction can be ready (see instReady() even if this method returns true.

Definition at line 116 of file decoder.hh.

References outOfBytes.

◆ pcMask()

Addr gem5::InstDecoder::pcMask ( ) const
inline

Definition at line 97 of file decoder.hh.

References _pcMask.

Referenced by gem5::o3::Fetch::fetch().

◆ reset()

virtual void gem5::InstDecoder::reset ( )
inlinevirtual

◆ takeOverFrom()

virtual void gem5::InstDecoder::takeOverFrom ( InstDecoder old)
inlinevirtual

Take over the state from an old decoder when switching CPUs.

Parameters
oldDecoder used in old CPU

Reimplemented in gem5::X86ISA::Decoder.

Definition at line 89 of file decoder.hh.

References instDone, and outOfBytes.

Referenced by gem5::SimpleThread::takeOverFrom(), gem5::o3::ThreadContext::takeOverFrom(), and gem5::X86ISA::Decoder::takeOverFrom().

Member Data Documentation

◆ _moreBytesPtr

void* gem5::InstDecoder::_moreBytesPtr
protected

Definition at line 45 of file decoder.hh.

Referenced by moreBytesPtr().

◆ _moreBytesSize

size_t gem5::InstDecoder::_moreBytesSize
protected

Definition at line 46 of file decoder.hh.

Referenced by moreBytesSize().

◆ _pcMask

Addr gem5::InstDecoder::_pcMask
protected

Definition at line 47 of file decoder.hh.

Referenced by pcMask().

◆ instDone

bool gem5::InstDecoder::instDone = false
protected

◆ outOfBytes

bool gem5::InstDecoder::outOfBytes = true
protected

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

Generated on Tue Dec 21 2021 11:35:04 for gem5 by doxygen 1.8.17