rename.hh revision 1062 
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.)
15template<class Impl>
16class 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 regStats();
58
59    void setCPU(FullCPU *cpu_ptr);
60
61    void setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr);
62
63    void setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr);
64
65    void setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr);
66
67    void setRenameMap(RenameMap *rm_ptr);
68
69    void setFreeList(FreeList *fl_ptr);
70
71    void dumpHistory();
72
73    void tick();
74
75    void rename();
76
77    void squash();
78
79  private:
80    void block();
81
82    inline void unblock();
83
84    void doSquash();
85
86    void removeFromHistory(InstSeqNum inst_seq_num);
87
88    inline void renameSrcRegs(DynInstPtr &inst);
89
90    inline void renameDestRegs(DynInstPtr &inst);
91
92    inline int calcFreeROBEntries();
93
94    inline int calcFreeIQEntries();
95
96    /** Holds the previous information for each rename.
97     *  Note that often times the inst may have been deleted, so only access
98     *  the pointer for the address and do not dereference it.
99     */
100    struct RenameHistory {
101        RenameHistory(InstSeqNum _instSeqNum, RegIndex _archReg,
102                      PhysRegIndex _newPhysReg, PhysRegIndex _prevPhysReg)
103            : instSeqNum(_instSeqNum), archReg(_archReg),
104              newPhysReg(_newPhysReg), prevPhysReg(_prevPhysReg),
105              placeHolder(false)
106        {
107        }
108
109        /** Constructor used specifically for cases where a place holder
110         *  rename history entry is being made.
111         */
112        RenameHistory(InstSeqNum _instSeqNum)
113            : instSeqNum(_instSeqNum), archReg(0), newPhysReg(0),
114              prevPhysReg(0), placeHolder(true)
115        {
116        }
117
118        InstSeqNum instSeqNum;
119        RegIndex archReg;
120        PhysRegIndex newPhysReg;
121        PhysRegIndex prevPhysReg;
122        bool placeHolder;
123    };
124
125    std::list<RenameHistory> historyBuffer;
126
127    /** CPU interface. */
128    FullCPU *cpu;
129
130    // Interfaces to objects outside of rename.
131    /** Time buffer interface. */
132    TimeBuffer<TimeStruct> *timeBuffer;
133
134    /** Wire to get IEW's output from backwards time buffer. */
135    typename TimeBuffer<TimeStruct>::wire fromIEW;
136
137    /** Wire to get commit's output from backwards time buffer. */
138    typename TimeBuffer<TimeStruct>::wire fromCommit;
139
140    /** Wire to write infromation heading to previous stages. */
141    // Might not be the best name as not only decode will read it.
142    typename TimeBuffer<TimeStruct>::wire toDecode;
143
144    /** Rename instruction queue. */
145    TimeBuffer<RenameStruct> *renameQueue;
146
147    /** Wire to write any information heading to IEW. */
148    typename TimeBuffer<RenameStruct>::wire toIEW;
149
150    /** Decode instruction queue interface. */
151    TimeBuffer<DecodeStruct> *decodeQueue;
152
153    /** Wire to get decode's output from decode queue. */
154    typename TimeBuffer<DecodeStruct>::wire fromDecode;
155
156    /** Skid buffer between rename and decode. */
157    std::queue<DecodeStruct> skidBuffer;
158
159    /** Rename map interface. */
160    SimpleRenameMap *renameMap;
161
162    /** Free list interface. */
163    FreeList *freeList;
164
165    /** Delay between iew and rename, in ticks. */
166    int iewToRenameDelay;
167
168    /** Delay between decode and rename, in ticks. */
169    int decodeToRenameDelay;
170
171    /** Delay between commit and rename, in ticks. */
172    unsigned commitToRenameDelay;
173
174    /** Rename width, in instructions. */
175    unsigned renameWidth;
176
177    /** Commit width, in instructions.  Used so rename knows how many
178     *  instructions might have freed registers in the previous cycle.
179     */
180    unsigned commitWidth;
181
182    /** The instruction that rename is currently on.  It needs to have
183     *  persistent state so that when a stall occurs in the middle of a
184     *  group of instructions, it can restart at the proper instruction.
185     */
186    unsigned numInst;
187
188    Stats::Scalar<> renameSquashCycles;
189    Stats::Scalar<> renameIdleCycles;
190    Stats::Scalar<> renameBlockCycles;
191    Stats::Scalar<> renameUnblockCycles;
192    Stats::Scalar<> renameRenamedInsts;
193    Stats::Scalar<> renameSquashedInsts;
194    Stats::Scalar<> renameROBFullEvents;
195    Stats::Scalar<> renameIQFullEvents;
196    Stats::Scalar<> renameFullRegistersEvents;
197    Stats::Scalar<> renameRenamedOperands;
198    Stats::Scalar<> renameRenameLookups;
199    Stats::Scalar<> renameHBPlaceHolders;
200    Stats::Scalar<> renameCommittedMaps;
201    Stats::Scalar<> renameUndoneMaps;
202    Stats::Scalar<> renameValidUndoneMaps;
203};
204
205#endif // __SIMPLE_RENAME_HH__
206