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// Todo: Maybe have a special method for handling interrupts/traps.
//
// Traps: Have IEW send a signal to commit saying that there's a trap to
// be handled. Have commit send the PC back to the fetch stage, along
// with the current commit PC. Fetch will directly access the IPR and save
// off all the proper stuff. Commit can send out a squash, or something
// close to it.
// Do the same for hwrei(). However, requires that commit be specifically
// built to support that kind of stuff. Probably not horrible to have
// commit support having the CPU tell it to squash the other stages and
// restart at a given address. The IPR register does become an issue.
// Probably not a big deal if the IPR stuff isn't cycle accurate. Can just
// have the original function handle writing to the IPR register.
#ifndef __CPU_BETA_CPU_SIMPLE_COMMIT_HH__
#define __CPU_BETA_CPU_SIMPLE_COMMIT_HH__
#include "base/statistics.hh"
#include "base/timebuf.hh"
#include "mem/memory_interface.hh"
template<class Impl>
class SimpleCommit
{
public:
// Typedefs from the Impl.
typedef typename Impl::ISA ISA;
typedef typename Impl::FullCPU FullCPU;
typedef typename Impl::DynInstPtr DynInstPtr;
typedef typename Impl::Params Params;
typedef typename Impl::CPUPol CPUPol;
typedef typename CPUPol::ROB ROB;
typedef typename CPUPol::TimeStruct TimeStruct;
typedef typename CPUPol::IEWStruct IEWStruct;
typedef typename CPUPol::RenameStruct RenameStruct;
public:
// I don't believe commit can block, so it will only have two
// statuses for now.
// Actually if there's a cache access that needs to block (ie
// uncachable load or just a mem access in commit) then the stage
// may have to wait.
enum Status {
Running,
Idle,
ROBSquashing,
DcacheMissStall,
DcacheMissComplete
};
private:
Status _status;
public:
SimpleCommit(Params ¶ms);
void regStats();
void setCPU(FullCPU *cpu_ptr);
void setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr);
void setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr);
void setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr);
void setROB(ROB *rob_ptr);
void tick();
void commit();
private:
void commitInsts();
bool commitHead(DynInstPtr &head_inst, unsigned inst_num);
void getInsts();
void markCompletedInsts();
public:
uint64_t readCommitPC();
void setSquashing() { _status = ROBSquashing; }
private:
/** Time buffer interface. */
TimeBuffer<TimeStruct> *timeBuffer;
/** Wire to write information heading to previous stages. */
typename TimeBuffer<TimeStruct>::wire toIEW;
/** Wire to read information from IEW (for ROB). */
typename TimeBuffer<TimeStruct>::wire robInfoFromIEW;
/** IEW instruction queue interface. */
TimeBuffer<IEWStruct> *iewQueue;
/** Wire to read information from IEW queue. */
typename TimeBuffer<IEWStruct>::wire fromIEW;
/** Rename instruction queue interface, for ROB. */
TimeBuffer<RenameStruct> *renameQueue;
/** Wire to read information from rename queue. */
typename TimeBuffer<RenameStruct>::wire fromRename;
/** ROB interface. */
ROB *rob;
/** Pointer to FullCPU. */
FullCPU *cpu;
/** Memory interface. Used for d-cache accesses. */
MemInterface *dcacheInterface;
private:
/** IEW to Commit delay, in ticks. */
unsigned iewToCommitDelay;
/** Rename to ROB delay, in ticks. */
unsigned renameToROBDelay;
/** Rename width, in instructions. Used so ROB knows how many
* instructions to get from the rename instruction queue.
*/
unsigned renameWidth;
/** IEW width, in instructions. Used so ROB knows how many
* instructions to get from the IEW instruction queue.
*/
unsigned iewWidth;
/** Commit width, in instructions. */
unsigned commitWidth;
Stats::Scalar<> commitCommittedInsts;
Stats::Scalar<> commitSquashedInsts;
Stats::Scalar<> commitSquashEvents;
Stats::Scalar<> commitNonSpecStalls;
Stats::Scalar<> commitCommittedBranches;
Stats::Scalar<> commitCommittedLoads;
Stats::Scalar<> commitCommittedMemRefs;
Stats::Scalar<> branchMispredicts;
Stats::Distribution<> n_committed_dist;
};
#endif // __CPU_BETA_CPU_SIMPLE_COMMIT_HH__
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