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32 #ifndef __CPU_O3_ROB_HH__
33 #define __CPU_O3_ROB_HH__
39 #include "arch/registers.hh"
40 #include "base/types.hh"
41 #include "config/the_isa.hh"
44 * ROB class. The ROB is largely what drives squashing.
50 typedef TheISA::RegIndex RegIndex;
52 //Typedefs from the Impl.
53 typedef typename Impl::O3CPU O3CPU;
54 typedef typename Impl::DynInstPtr DynInstPtr;
56 typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo;
57 typedef typename std::list<DynInstPtr>::iterator InstIt;
59 /** Possible ROB statuses. */
66 /** SMT ROB Sharing Policy */
74 /** Per-thread ROB status. */
75 Status robStatus[Impl::MaxThreads];
77 /** ROB resource sharing policy for SMT mode. */
82 * @param _numEntries Number of entries in ROB.
83 * @param _squashWidth Number of instructions that can be squashed in a
85 * @param _smtROBPolicy ROB Partitioning Scheme for SMT.
86 * @param _smtROBThreshold Max Resources(by %) a thread can have in the ROB.
87 * @param _numThreads The number of active threads.
89 ROB(O3CPU *_cpu, unsigned _numEntries, unsigned _squashWidth,
90 std::string smtROBPolicy, unsigned _smtROBThreshold,
91 ThreadID _numThreads);
93 std::string name() const;
95 /** Sets pointer to the list of active threads.
96 * @param at_ptr Pointer to the list of active threads.
98 void setActiveThreads(std::list<ThreadID> *at_ptr);
100 /** Switches out the ROB. */
103 /** Takes over another CPU's thread. */
106 /** Function to insert an instruction into the ROB. Note that whatever
107 * calls this function must ensure that there is enough space within the
108 * ROB for the new instruction.
109 * @param inst The instruction being inserted into the ROB.
111 void insertInst(DynInstPtr &inst);
113 /** Returns pointer to the head instruction within the ROB. There is
114 * no guarantee as to the return value if the ROB is empty.
115 * @retval Pointer to the DynInst that is at the head of the ROB.
117 // DynInstPtr readHeadInst();
119 /** Returns a pointer to the head instruction of a specific thread within
121 * @return Pointer to the DynInst that is at the head of the ROB.
123 DynInstPtr readHeadInst(ThreadID tid);
125 /** Returns a pointer to the instruction with the given sequence if it is
128 DynInstPtr findInst(ThreadID tid, InstSeqNum squash_inst);
130 /** Returns pointer to the tail instruction within the ROB. There is
131 * no guarantee as to the return value if the ROB is empty.
132 * @retval Pointer to the DynInst that is at the tail of the ROB.
134 // DynInstPtr readTailInst();
136 /** Returns a pointer to the tail instruction of a specific thread within
138 * @return Pointer to the DynInst that is at the tail of the ROB.
140 DynInstPtr readTailInst(ThreadID tid);
142 /** Retires the head instruction, removing it from the ROB. */
143 // void retireHead();
145 /** Retires the head instruction of a specific thread, removing it from the
148 void retireHead(ThreadID tid);
150 /** Is the oldest instruction across all threads ready. */
151 // bool isHeadReady();
153 /** Is the oldest instruction across a particular thread ready. */
154 bool isHeadReady(ThreadID tid);
156 /** Is there any commitable head instruction across all threads ready. */
159 /** Re-adjust ROB partitioning. */
162 /** Number of entries needed For 'num_threads' amount of threads. */
163 int entryAmount(ThreadID num_threads);
165 /** Returns the number of total free entries in the ROB. */
166 unsigned numFreeEntries();
168 /** Returns the number of free entries in a specific ROB paritition. */
169 unsigned numFreeEntries(ThreadID tid);
171 /** Returns the maximum number of entries for a specific thread. */
172 unsigned getMaxEntries(ThreadID tid)
173 { return maxEntries[tid]; }
175 /** Returns the number of entries being used by a specific thread. */
176 unsigned getThreadEntries(ThreadID tid)
177 { return threadEntries[tid]; }
179 /** Returns if the ROB is full. */
181 { return numInstsInROB == numEntries; }
183 /** Returns if a specific thread's partition is full. */
184 bool isFull(ThreadID tid)
185 { return threadEntries[tid] == numEntries; }
187 /** Returns if the ROB is empty. */
189 { return numInstsInROB == 0; }
191 /** Returns if a specific thread's partition is empty. */
192 bool isEmpty(ThreadID tid)
193 { return threadEntries[tid] == 0; }
195 /** Executes the squash, marking squashed instructions. */
196 void doSquash(ThreadID tid);
198 /** Squashes all instructions younger than the given sequence number for
199 * the specific thread.
201 void squash(InstSeqNum squash_num, ThreadID tid);
203 /** Updates the head instruction with the new oldest instruction. */
206 /** Updates the tail instruction with the new youngest instruction. */
209 /** Reads the PC of the oldest head instruction. */
210 // uint64_t readHeadPC();
212 /** Reads the PC of the head instruction of a specific thread. */
213 // uint64_t readHeadPC(ThreadID tid);
215 /** Reads the next PC of the oldest head instruction. */
216 // uint64_t readHeadNextPC();
218 /** Reads the next PC of the head instruction of a specific thread. */
219 // uint64_t readHeadNextPC(ThreadID tid);
221 /** Reads the sequence number of the oldest head instruction. */
222 // InstSeqNum readHeadSeqNum();
224 /** Reads the sequence number of the head instruction of a specific thread.
226 // InstSeqNum readHeadSeqNum(ThreadID tid);
228 /** Reads the PC of the youngest tail instruction. */
229 // uint64_t readTailPC();
231 /** Reads the PC of the tail instruction of a specific thread. */
232 // uint64_t readTailPC(ThreadID tid);
234 /** Reads the sequence number of the youngest tail instruction. */
235 // InstSeqNum readTailSeqNum();
237 /** Reads the sequence number of tail instruction of a specific thread. */
238 // InstSeqNum readTailSeqNum(ThreadID tid);
240 /** Checks if the ROB is still in the process of squashing instructions.
241 * @retval Whether or not the ROB is done squashing.
243 bool isDoneSquashing(ThreadID tid) const
244 { return doneSquashing[tid]; }
246 /** Checks if the ROB is still in the process of squashing instructions for
249 bool isDoneSquashing();
251 /** This is more of a debugging function than anything. Use
252 * numInstsInROB to get the instructions in the ROB unless you are
253 * double checking that variable.
257 /** This is more of a debugging function than anything. Use
258 * threadEntries to get the instructions in the ROB unless you are
259 * double checking that variable.
261 int countInsts(ThreadID tid);
263 /** Registers statistics. */
267 /** Pointer to the CPU. */
270 /** Active Threads in CPU */
271 std::list<ThreadID> *activeThreads;
273 /** Number of instructions in the ROB. */
276 /** Entries Per Thread */
277 unsigned threadEntries[Impl::MaxThreads];
279 /** Max Insts a Thread Can Have in the ROB */
280 unsigned maxEntries[Impl::MaxThreads];
282 /** ROB List of Instructions */
283 std::list<DynInstPtr> instList[Impl::MaxThreads];
285 /** Number of instructions that can be squashed in a single cycle. */
286 unsigned squashWidth;
289 /** Iterator pointing to the instruction which is the last instruction
290 * in the ROB. This may at times be invalid (ie when the ROB is empty),
291 * however it should never be incorrect.
295 /** Iterator pointing to the instruction which is the first instruction in
300 /** Iterator used for walking through the list of instructions when
301 * squashing. Used so that there is persistent state between cycles;
302 * when squashing, the instructions are marked as squashed but not
303 * immediately removed, meaning the tail iterator remains the same before
304 * and after a squash.
305 * This will always be set to cpu->instList.end() if it is invalid.
307 InstIt squashIt[Impl::MaxThreads];
310 /** Number of instructions in the ROB. */
313 /** Dummy instruction returned if there are no insts left. */
314 DynInstPtr dummyInst;
317 /** The sequence number of the squashed instruction. */
318 InstSeqNum squashedSeqNum[Impl::MaxThreads];
320 /** Is the ROB done squashing. */
321 bool doneSquashing[Impl::MaxThreads];
323 /** Number of active threads. */
326 // The number of rob_reads
327 Stats::Scalar robReads;
328 // The number of rob_writes
329 Stats::Scalar robWrites;
332 #endif //__CPU_O3_ROB_HH__