gem5/src/cpu/inorder/inorder_dyn_inst.hh

/*
 * Copyright (c) 2007 MIPS Technologies, Inc.
 * Copyright (c) 2004-2006 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Kevin Lim
 *          Korey Sewell
 */

#ifndef __CPU_INORDER_DYN_INST_HH__
#define __CPU_INORDER_DYN_INST_HH__

#include <bitset>
#include <list>
#include <string>

#include "arch/isa_traits.hh"
#include "arch/faults.hh"
#include "arch/types.hh"
#include "arch/mt.hh"
#include "base/fast_alloc.hh"
#include "base/trace.hh"
#include "cpu/inorder/inorder_trace.hh"
#include "config/full_system.hh"
#include "cpu/thread_context.hh"
#include "cpu/exetrace.hh"
#include "cpu/inst_seq.hh"
#include "cpu/op_class.hh"
#include "cpu/static_inst.hh"
#include "cpu/inorder/thread_state.hh"
#include "cpu/inorder/resource.hh"
#include "cpu/inorder/pipeline_traits.hh"
#include "mem/packet.hh"
#include "sim/system.hh"

/**
 * @file
 * Defines a dynamic instruction context for a inorder CPU model.
 */

// Forward declaration.
class StaticInstPtr;
class ResourceRequest;

class InOrderDynInst : public FastAlloc, public RefCounted
{
  public:
    // Binary machine instruction type.
    typedef TheISA::MachInst MachInst;
    // Extended machine instruction type
    typedef TheISA::ExtMachInst ExtMachInst;
    // Logical register index type.
    typedef TheISA::RegIndex RegIndex;
    // Integer register type.
    typedef TheISA::IntReg IntReg;
    // Floating point register type.
    typedef TheISA::FloatReg FloatReg;
    // Floating point register type.
    typedef TheISA::MiscReg MiscReg;

    typedef short int PhysRegIndex;

    /** The refcounted DynInst pointer to be used.  In most cases this is
     *  what should be used, and not DynInst*.
     */
    typedef RefCountingPtr<InOrderDynInst> DynInstPtr;

    // The list of instructions iterator type.
    typedef std::list<DynInstPtr>::iterator ListIt;

    enum {
        MaxInstSrcRegs = TheISA::MaxInstSrcRegs,	/// Max source regs
        MaxInstDestRegs = TheISA::MaxInstDestRegs,	/// Max dest regs
    };

  public:
    /** BaseDynInst constructor given a binary instruction.
     *  @param inst The binary instruction.
     *  @param PC The PC of the instruction.
     *  @param pred_PC The predicted next PC.
     *  @param seq_num The sequence number of the instruction.
     *  @param cpu Pointer to the instruction's CPU.
     */
    InOrderDynInst(ExtMachInst inst, Addr PC, Addr pred_PC, InstSeqNum seq_num,
                 InOrderCPU *cpu);

    /** BaseDynInst constructor given a binary instruction.
     *  @param seq_num The sequence number of the instruction.
     *  @param cpu Pointer to the instruction's CPU.
     *  NOTE: Must set Binary Instrution through Member Function
     */
    InOrderDynInst(InOrderCPU *cpu, InOrderThreadState *state, InstSeqNum seq_num,
                   unsigned tid, unsigned asid = 0);

    /** BaseDynInst constructor given a StaticInst pointer.
     *  @param _staticInst The StaticInst for this BaseDynInst.
     */
    InOrderDynInst(StaticInstPtr &_staticInst);

    /** Skeleton Constructor. */
    InOrderDynInst();

    /** InOrderDynInst destructor. */
    ~InOrderDynInst();

  public:
    /** The sequence number of the instruction. */
    InstSeqNum seqNum;

    /** The sequence number of the instruction. */
    InstSeqNum bdelaySeqNum;

    enum Status {
        RegDepMapEntry,          /// Instruction has been entered onto the RegDepMap
        IqEntry,                 /// Instruction is in the IQ
        RobEntry,                /// Instruction is in the ROB
        LsqEntry,                /// Instruction is in the LSQ
        Completed,               /// Instruction has completed
        ResultReady,             /// Instruction has its result
        CanIssue,                /// Instruction can issue and execute
        Issued,                  /// Instruction has issued
        Executed,                /// Instruction has executed
        CanCommit,               /// Instruction can commit
        AtCommit,                /// Instruction has reached commit
        Committed,               /// Instruction has committed
        Squashed,                /// Instruction is squashed
        SquashedInIQ,            /// Instruction is squashed in the IQ
        SquashedInLSQ,           /// Instruction is squashed in the LSQ
        SquashedInROB,           /// Instruction is squashed in the ROB
        RecoverInst,             /// Is a recover instruction
        BlockingInst,            /// Is a blocking instruction
        ThreadsyncWait,          /// Is a thread synchronization instruction
        SerializeBefore,         /// Needs to serialize on
                                 /// instructions ahead of it
        SerializeAfter,          /// Needs to serialize instructions behind it
        SerializeHandled,        /// Serialization has been handled
        NumStatus
    };

    /** The status of this BaseDynInst.  Several bits can be set. */
    std::bitset<NumStatus> status;

    /** The thread this instruction is from. */
    short threadNumber;

    /** data address space ID, for loads & stores. */
    short asid;

    /** The virtual processor number */
    short virtProcNumber;

    /** The StaticInst used by this BaseDynInst. */
    StaticInstPtr staticInst;

    /** InstRecord that tracks this instructions. */
    Trace::InOrderTraceRecord *traceData;

    /** Pointer to the Impl's CPU object. */
    InOrderCPU *cpu;

    /** Pointer to the thread state. */
    InOrderThreadState *thread;

    /** The kind of fault this instruction has generated. */
    Fault fault;

    /** The memory request. */
    Request *req;

    /** Pointer to the data for the memory access. */
    uint8_t *memData;

    /**  Data used for a store for operation. */
    uint64_t loadData;

    /**  Data used for a store for operation. */
    uint64_t storeData;

    /** The resource schedule for this inst */
    ThePipeline::ResSchedule resSched;

    /** List of active resource requests for this instruction */
    std::list<ResourceRequest*> reqList;

    /** The effective virtual address (lds & stores only). */
    Addr effAddr;

    /** The effective physical address. */
    Addr physEffAddr;

    /** Effective virtual address for a copy source. */
    Addr copySrcEffAddr;

    /** Effective physical address for a copy source. */
    Addr copySrcPhysEffAddr;

    /** The memory request flags (from translation). */
    unsigned memReqFlags;

    /** How many source registers are ready. */
    unsigned readyRegs;

    /** An instruction src/dest has to be one of these types */
    union InstValue {
        uint64_t integer;
        double dbl;
    };

    //@TODO: Naming Convention for Enums?
    enum ResultType {
        None,
        Integer,
        Float,
        Double
    };


    /** Result of an instruction execution */
    struct InstResult {
        ResultType type;
        InstValue val;
        Tick tick;
        int width;

        InstResult()
            : type(None), tick(0), width(0)
        {}
    };

    /** The source of the instruction; assumes for now that there's only one
     *  destination register.
     */
    InstValue instSrc[MaxInstSrcRegs];

    /** The result of the instruction; assumes for now that there's only one
     *  destination register.
     */
    InstResult instResult[MaxInstDestRegs];

    /** PC of this instruction. */
    Addr PC;

    /** Next non-speculative PC.  It is not filled in at fetch, but rather
     *  once the target of the branch is truly known (either decode or
     *  execute).
     */
    Addr nextPC;

    /** Next next non-speculative PC.  It is not filled in at fetch, but rather
     *  once the target of the branch is truly known (either decode or
     *  execute).
     */
    Addr nextNPC;

    /** Predicted next PC. */
    Addr predPC;

    /** Predicted next NPC. */
    Addr predNPC;

    /** Predicted next microPC */
    Addr predMicroPC;

    /** Address to fetch from */
    Addr fetchAddr;

    /** Address to get/write data from/to */
    Addr memAddr;

    /** Whether or not the source register is ready.
     *  @todo: Not sure this should be here vs the derived class.
     */
    bool _readySrcRegIdx[MaxInstSrcRegs];

    /** Physical register index of the destination registers of this
     *  instruction.
     */
    PhysRegIndex _destRegIdx[MaxInstDestRegs];

    /** Physical register index of the source registers of this
     *  instruction.
     */
    PhysRegIndex _srcRegIdx[MaxInstSrcRegs];

    /** Physical register index of the previous producers of the
     *  architected destinations.
     */
    PhysRegIndex _prevDestRegIdx[MaxInstDestRegs];

    int nextStage;

    /* vars to keep track of InstStage's - used for resource sched defn */
    int nextInstStageNum;
    ThePipeline::InstStage *currentInstStage;
    std::list<ThePipeline::InstStage*> instStageList;

  private:
    /** Function to initialize variables in the constructors. */
    void initVars();

  public:
    Tick memTime;

    ////////////////////////////////////////////////////////////
    //
    //  BASE INSTRUCTION INFORMATION.
    //
    ////////////////////////////////////////////////////////////
    std::string instName() { return staticInst->getName(); }


    void setMachInst(ExtMachInst inst);

    /** Sets the StaticInst. */
    void setStaticInst(StaticInstPtr &static_inst);

    /** Sets the sequence number. */
    void setSeqNum(InstSeqNum seq_num) { seqNum = seq_num; }

    /** Sets the ASID. */
    void setASID(short addr_space_id) { asid = addr_space_id; }

    /** Reads the thread id. */
    short readTid() { return threadNumber; }

    /** Sets the thread id. */
    void setTid(unsigned tid) { threadNumber = tid; }

    void setVpn(int id) { virtProcNumber = id; }

    int readVpn() { return virtProcNumber; }

    /** Sets the pointer to the thread state. */
    void setThreadState(InOrderThreadState *state) { thread = state; }

    /** Returns the thread context. */
    ThreadContext *tcBase() { return thread->getTC(); }

    /** Returns the fault type. */
    Fault getFault() { return fault; }

    ////////////////////////////////////////////////////////////
    //
    //  INSTRUCTION TYPES -  Forward checks to StaticInst object.
    //
    ////////////////////////////////////////////////////////////
    bool isNop()	  const { return staticInst->isNop(); }
    bool isMemRef()    	  const { return staticInst->isMemRef(); }
    bool isLoad()	  const { return staticInst->isLoad(); }
    bool isStore()	  const { return staticInst->isStore(); }
    bool isStoreConditional() const
    { return staticInst->isStoreConditional(); }
    bool isInstPrefetch() const { return staticInst->isInstPrefetch(); }
    bool isDataPrefetch() const { return staticInst->isDataPrefetch(); }
    bool isCopy()         const { return staticInst->isCopy(); }
    bool isInteger()	  const { return staticInst->isInteger(); }
    bool isFloating()	  const { return staticInst->isFloating(); }
    bool isControl()	  const { return staticInst->isControl(); }
    bool isCall()	  const { return staticInst->isCall(); }
    bool isReturn()	  const { return staticInst->isReturn(); }
    bool isDirectCtrl()	  const { return staticInst->isDirectCtrl(); }
    bool isIndirectCtrl() const { return staticInst->isIndirectCtrl(); }
    bool isCondCtrl()	  const { return staticInst->isCondCtrl(); }
    bool isUncondCtrl()	  const { return staticInst->isUncondCtrl(); }
    bool isCondDelaySlot() const { return staticInst->isCondDelaySlot(); }

    bool isThreadSync()   const { return staticInst->isThreadSync(); }
    bool isSerializing()  const { return staticInst->isSerializing(); }
    bool isSerializeBefore() const
    { return staticInst->isSerializeBefore() || status[SerializeBefore]; }
    bool isSerializeAfter() const
    { return staticInst->isSerializeAfter() || status[SerializeAfter]; }
    bool isMemBarrier()   const { return staticInst->isMemBarrier(); }
    bool isWriteBarrier() const { return staticInst->isWriteBarrier(); }
    bool isNonSpeculative() const { return staticInst->isNonSpeculative(); }
    bool isQuiesce() const { return staticInst->isQuiesce(); }
    bool isIprAccess() const { return staticInst->isIprAccess(); }
    bool isUnverifiable() const { return staticInst->isUnverifiable(); }

    /////////////////////////////////////////////
    //
    // RESOURCE SCHEDULING
    //
    /////////////////////////////////////////////

    void setNextStage(int stage_num) { nextStage = stage_num; }
    int getNextStage() { return nextStage; }

    ThePipeline::InstStage *addStage();
    ThePipeline::InstStage *addStage(int stage);
    ThePipeline::InstStage *currentStage() { return currentInstStage; }
    void deleteStages();

    /** Add A Entry To Reource Schedule */
    void addToSched(ThePipeline::ScheduleEntry* sched_entry)
    { resSched.push(sched_entry); }


    /** Print Resource Schedule */
    /** @NOTE: DEBUG ONLY */
    void printSched()
    {
        ThePipeline::ResSchedule tempSched;
        std::cerr << "\tInst. Res. Schedule: ";
        while (!resSched.empty()) {
            std::cerr << '\t' << resSched.top()->stageNum << "-"
                 << resSched.top()->resNum << ", ";

            tempSched.push(resSched.top());
            resSched.pop();
        }

        std::cerr << std::endl;
        resSched = tempSched;
    }

    /** Return Next Resource Stage To Be Used */
    int nextResStage()
    {
        if (resSched.empty())
            return -1;
        else
            return resSched.top()->stageNum;
    }


    /** Return Next Resource To Be Used */
    int nextResource()
    {
        if (resSched.empty())
            return -1;
        else
            return resSched.top()->resNum;
    }

    /** Remove & Deallocate a schedule entry */
    void popSchedEntry()
    {
        if (!resSched.empty()) {
            ThePipeline::ScheduleEntry* sked = resSched.top();
            resSched.pop();
            delete sked;
        }
    }

    /** Release a Resource Request (Currently Unused) */
    void releaseReq(ResourceRequest* req);

    ////////////////////////////////////////////
    //
    // INSTRUCTION EXECUTION
    //
    ////////////////////////////////////////////
    /** Returns the opclass of this instruction. */
    OpClass opClass() const { return staticInst->opClass(); }

    /** Executes the instruction.*/
    Fault execute();

    unsigned curResSlot;

    unsigned getCurResSlot() { return curResSlot; }

    void setCurResSlot(unsigned slot_num) { curResSlot = slot_num; }

    /** Calls a syscall. */
    void syscall(int64_t callnum);
    void prefetch(Addr addr, unsigned flags);
    void writeHint(Addr addr, int size, unsigned flags);
    Fault copySrcTranslate(Addr src);
    Fault copy(Addr dest);

    ////////////////////////////////////////////////////////////
    //
    // MULTITHREADING INTERFACE TO CPU MODELS
    //
    ////////////////////////////////////////////////////////////
    virtual void deallocateContext(int thread_num);

    virtual void enableVirtProcElement(unsigned vpe);
    virtual void disableVirtProcElement(unsigned vpe);

    virtual void enableMultiThreading(unsigned vpe);
    virtual void disableMultiThreading(unsigned vpe);

    ////////////////////////////////////////////////////////////
    //
    //  PROGRAM COUNTERS - PC/NPC/NPC
    //
    ////////////////////////////////////////////////////////////
    /** Read the PC of this instruction. */
    const Addr readPC() const { return PC; }

    /** Sets the PC of this instruction. */
    void setPC(Addr pc) { PC = pc; }

    /** Returns the next PC.  This could be the speculative next PC if it is
     *  called prior to the actual branch target being calculated.
     */
    Addr readNextPC() { return nextPC; }

    /** Set the next PC of this instruction (its actual target). */
    void setNextPC(uint64_t val) { nextPC = val; }

    /** Returns the next NPC.  This could be the speculative next NPC if it is
     *  called prior to the actual branch target being calculated.
     */
    Addr readNextNPC()
    {
#if ISA_HAS_DELAY_SLOT
        return nextNPC;
#else
        return nextPC + sizeof(TheISA::MachInst);
#endif
    }

    /** Set the next PC of this instruction (its actual target). */
    void setNextNPC(uint64_t val) { nextNPC = val; }

    ////////////////////////////////////////////////////////////
    //
    // BRANCH PREDICTION
    //
    ////////////////////////////////////////////////////////////
    /** Set the predicted target of this current instruction. */
    void setPredTarg(Addr predicted_PC) { predPC = predicted_PC; }

    /** Returns the predicted target of the branch. */
    Addr readPredTarg() { return predPC; }

    /** Returns the predicted PC immediately after the branch. */
    Addr readPredPC() { return predPC; }

    /** Returns the predicted PC two instructions after the branch */
    Addr readPredNPC() { return predNPC; }

    /** Returns the predicted micro PC after the branch */
    Addr readPredMicroPC() { return predMicroPC; }

    /** Returns whether the instruction was predicted taken or not. */
    bool predTaken() { return predictTaken; }

    /** Returns whether the instruction mispredicted. */
    bool mispredicted()
    {
#if ISA_HAS_DELAY_SLOT
        return predPC != nextNPC;
#else
        return predPC != nextPC;
#endif
    }

    /** Returns whether the instruction mispredicted. */
    bool mistargeted() { return predPC != nextNPC; }

    /** Returns the branch target address. */
    Addr branchTarget() const { return staticInst->branchTarget(PC); }

    /** Checks whether or not this instruction has had its branch target
     *  calculated yet.  For now it is not utilized and is hacked to be
     *  always false.
     *  @todo: Actually use this instruction.
     */
    bool doneTargCalc() { return false; }

    void setBranchPred(bool prediction) { predictTaken = prediction; }

    int squashingStage;

    bool predictTaken;

    bool procDelaySlotOnMispred;

    ////////////////////////////////////////////
    //
    // MEMORY ACCESS
    //
    ////////////////////////////////////////////
    /**
     * Does a read to a given address.
     * @param addr The address to read.
     * @param data The read's data is written into this parameter.
     * @param flags The request's flags.
     * @return Returns any fault due to the read.
     */
    template <class T>
    Fault read(Addr addr, T &data, unsigned flags);

    /**
     * Does a write to a given address.
     * @param data The data to be written.
     * @param addr The address to write to.
     * @param flags The request's flags.
     * @param res The result of the write (for load locked/store conditionals).
     * @return Returns any fault due to the write.
     */
    template <class T>
    Fault write(T data, Addr addr, unsigned flags,
                        uint64_t *res);

    /** Initiates a memory access - Calculate Eff. Addr & Initiate Memory Access
     *  Only valid for memory operations.
     */
    Fault initiateAcc();

    /** Completes a memory access - Only valid for memory operations. */
    Fault completeAcc(Packet *pkt);

    /** Calculates Eff. Addr.  part of a memory instruction.  */
    Fault calcEA();

    /** Read Effective Address from instruction & do memory access */
    Fault memAccess();

    RequestPtr fetchMemReq;
    RequestPtr dataMemReq;

    bool memAddrReady;

    bool validMemAddr()
    { return memAddrReady; }

    void setMemAddr(Addr addr)
    { memAddr = addr; memAddrReady = true;}

    void unsetMemAddr()
    { memAddrReady = false;}

    Addr getMemAddr()
    { return memAddr; }

    /** Sets the effective address. */
    void setEA(Addr &ea) { instEffAddr = ea; eaCalcDone = true; }

    /** Returns the effective address. */
    const Addr &getEA() const { return instEffAddr; }

    /** Returns whether or not the eff. addr. calculation has been completed. */
    bool doneEACalc() { return eaCalcDone; }

    /** Returns whether or not the eff. addr. source registers are ready.
     *  Assume that src registers 1..n-1 are the ones that the
     *  EA calc depends on.  (i.e. src reg 0 is the source of the data to be
     *  stored)
     */
    bool eaSrcsReady()
    {
        for (int i = 1; i < numSrcRegs(); ++i) {
            if (!_readySrcRegIdx[i])
                return false;
        }

        return true;
    }

    //////////////////////////////////////////////////
    //
    // SOURCE-DESTINATION REGISTER INDEXING
    //
    //////////////////////////////////////////////////
    /** Returns the number of source registers. */
    int8_t numSrcRegs()	const { return staticInst->numSrcRegs(); }

    /** Returns the number of destination registers. */
    int8_t numDestRegs() const { return staticInst->numDestRegs(); }

    // the following are used to track physical register usage
    // for machines with separate int & FP reg files
    int8_t numFPDestRegs()  const { return staticInst->numFPDestRegs(); }
    int8_t numIntDestRegs() const { return staticInst->numIntDestRegs(); }

    /** Returns the logical register index of the i'th destination register. */
    RegIndex destRegIdx(int i) const { return staticInst->destRegIdx(i); }

    /** Returns the logical register index of the i'th source register. */
    RegIndex srcRegIdx(int i) const { return staticInst->srcRegIdx(i); }

    //////////////////////////////////////////////////
    //
    // RENAME/PHYSICAL REGISTER FILE SUPPORT
    //
    //////////////////////////////////////////////////
    /** Returns the physical register index of the i'th destination
     *  register.
     */
    PhysRegIndex renamedDestRegIdx(int idx) const
    {
        return _destRegIdx[idx];
    }

    /** Returns the physical register index of the i'th source register. */
    PhysRegIndex renamedSrcRegIdx(int idx) const
    {
        return _srcRegIdx[idx];
    }

    /** Returns the physical register index of the previous physical register
     *  that remapped to the same logical register index.
     */
    PhysRegIndex prevDestRegIdx(int idx) const
    {
        return _prevDestRegIdx[idx];
    }

    /** Returns if a source register is ready. */
    bool isReadySrcRegIdx(int idx) const
    {
        return this->_readySrcRegIdx[idx];
    }

    /** Records that one of the source registers is ready. */
    void markSrcRegReady()
    {
        if (++readyRegs == numSrcRegs()) {
            status.set(CanIssue);
        }
    }

    /** Marks a specific register as ready. */
    void markSrcRegReady(RegIndex src_idx)
    {
        _readySrcRegIdx[src_idx] = true;

        markSrcRegReady();
    }

    /** Renames a destination register to a physical register.  Also records
     *  the previous physical register that the logical register mapped to.
     */
    void renameDestReg(int idx,
                       PhysRegIndex renamed_dest,
                       PhysRegIndex previous_rename)
    {
        _destRegIdx[idx] = renamed_dest;
        _prevDestRegIdx[idx] = previous_rename;
    }

    /** Renames a source logical register to the physical register which
     *  has/will produce that logical register's result.
     *  @todo: add in whether or not the source register is ready.
     */
    void renameSrcReg(int idx, PhysRegIndex renamed_src)
    {
        _srcRegIdx[idx] = renamed_src;
    }


    PhysRegIndex readDestRegIdx(int idx)
    {
        return _destRegIdx[idx];
    }

    void setDestRegIdx(int idx, PhysRegIndex dest_idx)
    {
        _destRegIdx[idx] = dest_idx;
    }

    int getDestIdxNum(PhysRegIndex dest_idx)
    {
        for (int i=0; i < staticInst->numDestRegs(); i++) {
            if (_destRegIdx[i] == dest_idx)
                return i;
        }

        return -1;
    }

    PhysRegIndex readSrcRegIdx(int idx)
    {
        return _srcRegIdx[idx];
    }

    void setSrcRegIdx(int idx, PhysRegIndex src_idx)
    {
        _srcRegIdx[idx] = src_idx;
    }

    int getSrcIdxNum(PhysRegIndex src_idx)
    {
        for (int i=0; i < staticInst->numSrcRegs(); i++) {
            if (_srcRegIdx[i] == src_idx)
                return i;
        }

        return -1;
    }

    ////////////////////////////////////////////////////
    //
    // SOURCE-DESTINATION REGISTER VALUES
    //
    ////////////////////////////////////////////////////

    /** Functions that sets an integer or floating point
     *  source register to a value. */
    void setIntSrc(int idx, uint64_t val);
    void setFloatSrc(int idx, FloatReg val, int width = 32);
    void setFloatRegBitsSrc(int idx, uint64_t val);

    uint64_t* getIntSrcPtr(int idx) { return &instSrc[idx].integer; }
    uint64_t readIntSrc(int idx) { return instSrc[idx].integer; }

    /** These Instructions read a integer/float/misc. source register
     *  value in the instruction. The instruction's execute function will
     *  call these and it is the interface that is used by the ISA descr.
     *  language (which is why the name isnt readIntSrc(...)) Note: That
     *  the source reg. value is set using the setSrcReg() function.
     */
    IntReg readIntRegOperand(const StaticInst *si, int idx, unsigned tid=0);
    FloatReg readFloatRegOperand(const StaticInst *si, int idx,
                          int width = TheISA::SingleWidth);
    TheISA::FloatRegBits readFloatRegOperandBits(const StaticInst *si, int idx,
                                  int width = TheISA::SingleWidth);
    MiscReg readMiscReg(int misc_reg);
    MiscReg readMiscRegNoEffect(int misc_reg);
    MiscReg readMiscRegOperand(const StaticInst *si, int idx);
    MiscReg readMiscRegOperandNoEffect(const StaticInst *si, int idx);

    /** Returns the result value instruction. */
    ResultType resultType(int idx)
    {
        return instResult[idx].type;
    }

    uint64_t readIntResult(int idx)
    {
        return instResult[idx].val.integer;
    }

    /** Depending on type, return Float or Double */
    double readFloatResult(int idx)
    {
        //Should this function have a parameter for what width of return?x
       return (instResult[idx].type == Float) ?
           (float) instResult[idx].val.dbl : instResult[idx].val.dbl;
    }

    double readDoubleResult(int idx)
    {
        assert(instResult[idx].type == Double);
        return instResult[idx].val.dbl;
    }

    Tick readResultTime(int idx) { return instResult[idx].tick; }

    uint64_t* getIntResultPtr(int idx) { return &instResult[idx].val.integer; }

    /** This is the interface that an instruction will use to write
     *  it's destination register.
     */
    void setIntRegOperand(const StaticInst *si, int idx, IntReg val);
    void setFloatRegOperand(const StaticInst *si, int idx, FloatReg val,
                     int width = TheISA::SingleWidth);
    void setFloatRegOperandBits(const StaticInst *si, int idx, TheISA::FloatRegBits val,
                         int width = TheISA::SingleWidth);
    void setMiscReg(int misc_reg, const MiscReg &val);
    void setMiscRegNoEffect(int misc_reg, const MiscReg &val);
    void setMiscRegOperand(const StaticInst *si, int idx, const MiscReg &val);
    void setMiscRegOperandNoEffect(const StaticInst *si, int idx, const MiscReg &val);

    virtual uint64_t readRegOtherThread(unsigned idx, int tid = -1);
    virtual void setRegOtherThread(unsigned idx, const uint64_t &val, int tid = -1);

    /** Sets the number of consecutive store conditional failures. */
    void setStCondFailures(unsigned sc_failures)
    { thread->storeCondFailures = sc_failures; }

    //////////////////////////////////////////////////////////////
    //
    // INSTRUCTION STATUS FLAGS (READ/SET)
    //
    //////////////////////////////////////////////////////////////
    /** Sets this instruction as entered on the CPU Reg Dep Map */
    void setRegDepEntry() { status.set(RegDepMapEntry); }

    /** Returns whether or not the entry is on the CPU Reg Dep Map */
    bool isRegDepEntry() const { return status[RegDepMapEntry]; }

    /** Sets this instruction as completed. */
    void setCompleted() { status.set(Completed); }

    /** Returns whether or not this instruction is completed. */
    bool isCompleted() const { return status[Completed]; }

    /** Marks the result as ready. */
    void setResultReady() { status.set(ResultReady); }

    /** Returns whether or not the result is ready. */
    bool isResultReady() const { return status[ResultReady]; }

    /** Sets this instruction as ready to issue. */
    void setCanIssue() { status.set(CanIssue); }

    /** Returns whether or not this instruction is ready to issue. */
    bool readyToIssue() const { return status[CanIssue]; }

    /** Sets this instruction as issued from the IQ. */
    void setIssued() { status.set(Issued); }

    /** Returns whether or not this instruction has issued. */
    bool isIssued() const { return status[Issued]; }

    /** Sets this instruction as executed. */
    void setExecuted() { status.set(Executed); }

    /** Returns whether or not this instruction has executed. */
    bool isExecuted() const { return status[Executed]; }

    /** Sets this instruction as ready to commit. */
    void setCanCommit() { status.set(CanCommit); }

    /** Clears this instruction as being ready to commit. */
    void clearCanCommit() { status.reset(CanCommit); }

    /** Returns whether or not this instruction is ready to commit. */
    bool readyToCommit() const { return status[CanCommit]; }

    void setAtCommit() { status.set(AtCommit); }

    bool isAtCommit() { return status[AtCommit]; }

    /** Sets this instruction as committed. */
    void setCommitted() { status.set(Committed); }

    /** Returns whether or not this instruction is committed. */
    bool isCommitted() const { return status[Committed]; }

    /** Sets this instruction as squashed. */
    void setSquashed() { status.set(Squashed); }

    /** Returns whether or not this instruction is squashed. */
    bool isSquashed() const { return status[Squashed]; }

    /** Temporarily sets this instruction as a serialize before instruction. */
    void setSerializeBefore() { status.set(SerializeBefore); }

    /** Clears the serializeBefore part of this instruction. */
    void clearSerializeBefore() { status.reset(SerializeBefore); }

    /** Checks if this serializeBefore is only temporarily set. */
    bool isTempSerializeBefore() { return status[SerializeBefore]; }

    /** Temporarily sets this instruction as a serialize after instruction. */
    void setSerializeAfter() { status.set(SerializeAfter); }

    /** Clears the serializeAfter part of this instruction.*/
    void clearSerializeAfter() { status.reset(SerializeAfter); }

    /** Checks if this serializeAfter is only temporarily set. */
    bool isTempSerializeAfter() { return status[SerializeAfter]; }

    /** Sets the serialization part of this instruction as handled. */
    void setSerializeHandled() { status.set(SerializeHandled); }

    /** Checks if the serialization part of this instruction has been
     *  handled.  This does not apply to the temporary serializing
     *  state; it only applies to this instruction's own permanent
     *  serializing state.
     */
    bool isSerializeHandled() { return status[SerializeHandled]; }

  private:
    /** Instruction effective address.
     *  @todo: Consider if this is necessary or not.
     */
    Addr instEffAddr;

    /** Whether or not the effective address calculation is completed.
     *  @todo: Consider if this is necessary or not.
     */
    bool eaCalcDone;

  public:
    /** Whether or not the memory operation is done. */
    bool memOpDone;

  public:
    /** Load queue index. */
    int16_t lqIdx;

    /** Store queue index. */
    int16_t sqIdx;

    /** Iterator pointing to this BaseDynInst in the list of all insts. */
    ListIt instListIt;

    /** Returns iterator to this instruction in the list of all insts. */
    ListIt &getInstListIt() { return instListIt; }

    /** Sets iterator for this instruction in the list of all insts. */
    void setInstListIt(ListIt _instListIt) { instListIt = _instListIt; }

    /** Count of total number of dynamic instructions. */
    static int instcount;

    /** Dumps out contents of this BaseDynInst. */
    void dump();

    /** Dumps out contents of this BaseDynInst into given string. */
    void dump(std::string &outstring);


  //inline int curCount() { return curCount(); }
};


#endif // __CPU_BASE_DYN_INST_HH__