cpu/beta_cpu/rename.hh

   1 // Todo:
   2 // Fix up trap and barrier handling.
   3 // May want to have different statuses to differentiate the different stall
   4 // conditions.
   5
   6 #ifndef __SIMPLE_RENAME_HH__
   7 #define __SIMPLE_RENAME_HH__
   8
   9 #include <list>
  10
  11 #include "base/timebuf.hh"
  12
  13 // Will need rename maps for both the int reg file and fp reg file.
  14 // Or change rename map class to handle both. (RegFile handles both.)
  15 template<class Impl>
  16 class SimpleRename
  17 {
  18   public:
  19     // Typedefs from the Impl.
  20     typedef typename Impl::ISA ISA;
  21     typedef typename Impl::CPUPol CPUPol;
  22     typedef typename Impl::DynInstPtr DynInstPtr;
  23     typedef typename Impl::FullCPU FullCPU;
  24     typedef typename Impl::Params Params;
  25
  26     typedef typename CPUPol::FetchStruct FetchStruct;
  27     typedef typename CPUPol::DecodeStruct DecodeStruct;
  28     typedef typename CPUPol::RenameStruct RenameStruct;
  29     typedef typename CPUPol::TimeStruct TimeStruct;
  30
  31     // Typedefs from the CPUPol
  32     typedef typename CPUPol::FreeList FreeList;
  33     typedef typename CPUPol::RenameMap RenameMap;
  34
  35     // Typedefs from the ISA.
  36     typedef typename ISA::Addr Addr;
  37
  38   public:
  39     // Rename will block if ROB becomes full or issue queue becomes full,
  40     // or there are no free registers to rename to.
  41     // Only case where rename squashes is if IEW squashes.
  42     enum Status {
  43         Running,
  44         Idle,
  45         Squashing,
  46         Blocked,
  47         Unblocking,
  48         BarrierStall
  49     };
  50
  51   private:
  52     Status _status;
  53
  54   public:
  55     SimpleRename(Params &params);
  56
  57     void setCPU(FullCPU *cpu_ptr);
  58
  59     void setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr);
  60
  61     void setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr);
  62
  63     void setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr);
  64
  65     void setRenameMap(RenameMap *rm_ptr);
  66
  67     void setFreeList(FreeList *fl_ptr);
  68
  69     void dumpHistory();
  70
  71     void tick();
  72
  73     void rename();
  74
  75     void squash();
  76
  77   private:
  78     void block();
  79
  80     inline void unblock();
  81
  82     void doSquash();
  83
  84     void removeFromHistory(InstSeqNum inst_seq_num);
  85
  86     inline void renameSrcRegs(DynInstPtr &inst);
  87
  88     inline void renameDestRegs(DynInstPtr &inst);
  89
  90     inline int calcFreeROBEntries();
  91
  92     inline int calcFreeIQEntries();
  93
  94     /** Holds the previous information for each rename.
  95      *  Note that often times the inst may have been deleted, so only access
  96      *  the pointer for the address and do not dereference it.
  97      */
  98     struct RenameHistory {
  99         RenameHistory(InstSeqNum _instSeqNum, RegIndex _archReg,
 100                       PhysRegIndex _newPhysReg, PhysRegIndex _prevPhysReg)
 101             : instSeqNum(_instSeqNum), archReg(_archReg),
 102               newPhysReg(_newPhysReg), prevPhysReg(_prevPhysReg),
 103               placeHolder(false)
 104         {
 105         }
 106
 107         /** Constructor used specifically for cases where a place holder
 108          *  rename history entry is being made.
 109          */
 110         RenameHistory(InstSeqNum _instSeqNum)
 111             : instSeqNum(_instSeqNum), archReg(0), newPhysReg(0),
 112               prevPhysReg(0), placeHolder(true)
 113         {
 114         }
 115
 116         InstSeqNum instSeqNum;
 117         RegIndex archReg;
 118         PhysRegIndex newPhysReg;
 119         PhysRegIndex prevPhysReg;
 120         bool placeHolder;
 121     };
 122
 123     std::list<RenameHistory> historyBuffer;
 124
 125     /** CPU interface. */
 126     FullCPU *cpu;
 127
 128     // Interfaces to objects outside of rename.
 129     /** Time buffer interface. */
 130     TimeBuffer<TimeStruct> *timeBuffer;
 131
 132     /** Wire to get IEW's output from backwards time buffer. */
 133     typename TimeBuffer<TimeStruct>::wire fromIEW;
 134
 135     /** Wire to get commit's output from backwards time buffer. */
 136     typename TimeBuffer<TimeStruct>::wire fromCommit;
 137
 138     /** Wire to write infromation heading to previous stages. */
 139     // Might not be the best name as not only decode will read it.
 140     typename TimeBuffer<TimeStruct>::wire toDecode;
 141
 142     /** Rename instruction queue. */
 143     TimeBuffer<RenameStruct> *renameQueue;
 144
 145     /** Wire to write any information heading to IEW. */
 146     typename TimeBuffer<RenameStruct>::wire toIEW;
 147
 148     /** Decode instruction queue interface. */
 149     TimeBuffer<DecodeStruct> *decodeQueue;
 150
 151     /** Wire to get decode's output from decode queue. */
 152     typename TimeBuffer<DecodeStruct>::wire fromDecode;
 153
 154     /** Skid buffer between rename and decode. */
 155     std::queue<DecodeStruct> skidBuffer;
 156
 157     /** Rename map interface. */
 158     SimpleRenameMap *renameMap;
 159
 160     /** Free list interface. */
 161     FreeList *freeList;
 162
 163     /** Delay between iew and rename, in ticks. */
 164     int iewToRenameDelay;
 165
 166     /** Delay between decode and rename, in ticks. */
 167     int decodeToRenameDelay;
 168
 169     /** Delay between commit and rename, in ticks. */
 170     unsigned commitToRenameDelay;
 171
 172     /** Rename width, in instructions. */
 173     unsigned renameWidth;
 174
 175     /** Commit width, in instructions.  Used so rename knows how many
 176      *  instructions might have freed registers in the previous cycle.
 177      */
 178     unsigned commitWidth;
 179
 180     /** The instruction that rename is currently on.  It needs to have
 181      *  persistent state so that when a stall occurs in the middle of a
 182      *  group of instructions, it can restart at the proper instruction.
 183      */
 184     unsigned numInst;
 185 };
 186
 187 #endif // __SIMPLE_RENAME_HH__