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//Todo: Update with statuses.
//Need to handle delaying writes to the writeback bus if it's full at the
//given time. Load store queue.
#ifndef __SIMPLE_IEW_HH__
#define __SIMPLE_IEW_HH__
#include <queue>
#include "base/timebuf.hh"
#include "cpu/beta_cpu/comm.hh"
//Can IEW even stall? Space should be available/allocated already...maybe
//if there's not enough write ports on the ROB or waiting for CDB
//arbitration.
template<class Impl, class IQ>
class SimpleIEW
{
private:
//Typedefs from Impl
typedef typename Impl::ISA ISA;
typedef typename Impl::CPUPol CPUPol;
typedef typename Impl::DynInstPtr DynInstPtr;
typedef typename Impl::FullCPU FullCPU;
typedef typename Impl::Params Params;
typedef typename CPUPol::RenameMap RenameMap;
typedef typename CPUPol::LDSTQ LDSTQ;
typedef typename CPUPol::TimeStruct TimeStruct;
typedef typename CPUPol::IEWStruct IEWStruct;
typedef typename CPUPol::RenameStruct RenameStruct;
typedef typename CPUPol::IssueStruct IssueStruct;
public:
enum Status {
Running,
Blocked,
Idle,
Squashing,
Unblocking
};
private:
Status _status;
Status _issueStatus;
Status _exeStatus;
Status _wbStatus;
public:
void squash();
void squash(DynInstPtr &inst);
void block();
inline void unblock();
public:
SimpleIEW(Params ¶ms);
void setCPU(FullCPU *cpu_ptr);
void setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr);
void setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr);
void setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr);
void setRenameMap(RenameMap *rm_ptr);
void wakeDependents(DynInstPtr &inst);
void tick();
void iew();
private:
//Interfaces to objects inside and outside of IEW.
/** Time buffer interface. */
TimeBuffer<TimeStruct> *timeBuffer;
/** Wire to get commit's output from backwards time buffer. */
typename TimeBuffer<TimeStruct>::wire fromCommit;
/** Wire to write information heading to previous stages. */
typename TimeBuffer<TimeStruct>::wire toRename;
/** Rename instruction queue interface. */
TimeBuffer<RenameStruct> *renameQueue;
/** Wire to get rename's output from rename queue. */
typename TimeBuffer<RenameStruct>::wire fromRename;
/** Issue stage queue. */
TimeBuffer<IssueStruct> issueToExecQueue;
/** Wire to read information from the issue stage time queue. */
typename TimeBuffer<IssueStruct>::wire fromIssue;
/**
* IEW stage time buffer. Holds ROB indices of instructions that
* can be marked as completed.
*/
TimeBuffer<IEWStruct> *iewQueue;
/** Wire to write infromation heading to commit. */
typename TimeBuffer<IEWStruct>::wire toCommit;
//Will need internal queue to hold onto instructions coming from
//the rename stage in case of a stall.
/** Skid buffer between rename and IEW. */
std::queue<RenameStruct> skidBuffer;
/** Instruction queue. */
IQ instQueue;
LDSTQ ldstQueue;
/** Pointer to rename map. Might not want this stage to directly
* access this though...
*/
RenameMap *renameMap;
/** CPU interface. */
FullCPU *cpu;
private:
/** Commit to IEW delay, in ticks. */
unsigned commitToIEWDelay;
/** Rename to IEW delay, in ticks. */
unsigned renameToIEWDelay;
/**
* Issue to execute delay, in ticks. What this actually represents is
* the amount of time it takes for an instruction to wake up, be
* scheduled, and sent to a FU for execution.
*/
unsigned issueToExecuteDelay;
/** Width of issue's read path, in instructions. The read path is both
* the skid buffer and the rename instruction queue.
* Note to self: is this really different than issueWidth?
*/
unsigned issueReadWidth;
/** Width of issue, in instructions. */
unsigned issueWidth;
/** Width of execute, in instructions. Might make more sense to break
* down into FP vs int.
*/
unsigned executeWidth;
/** Number of cycles stage has been squashing. Used so that the stage
* knows when it can start unblocking, which is when the previous stage
* has received the stall signal and clears up its outputs.
*/
unsigned cyclesSquashing;
//Will implement later
//Load queue interface (probably one and the same)
//Store queue interface
};
#endif
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