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31 #ifndef __CPU_O3_FU_POOL_HH__
32 #define __CPU_O3_FU_POOL_HH__
39 #include "cpu/op_class.hh"
40 #include "params/FUPool.hh"
41 #include "sim/sim_object.hh"
47 * Pool of FU's, specific to the new CPU model. The old FU pool had lists of
48 * free units and busy units, and whenever a FU was needed it would iterate
49 * through the free units to find a FU that provided the capability. This pool
50 * has lists of units specific to each of the capabilities, and whenever a FU
51 * is needed, it iterates through that list to find a free unit. The previous
52 * FU pool would have to be ticked each cycle to update which units became
53 * free. This FU pool lets the IEW stage handle freeing units, which frees
54 * them as their scheduled execution events complete. This limits units in this
55 * model to either have identical issue and op latencies, or 1 cycle issue
58 class FUPool : public SimObject
61 /** Maximum op execution latencies, per op class. */
62 Cycles maxOpLatencies[Num_OpClasses];
63 /** Maximum issue latencies, per op class. */
64 Cycles maxIssueLatencies[Num_OpClasses];
66 /** Bitvector listing capabilities of this FU pool. */
67 std::bitset<Num_OpClasses> capabilityList;
69 /** Bitvector listing which FUs are busy. */
70 std::vector<bool> unitBusy;
72 /** List of units to be freed at the end of this cycle. */
73 std::vector<int> unitsToBeFreed;
76 * Class that implements a circular queue to hold FU indices. The hope is
77 * that FUs that have been just used will be moved to the end of the queue
78 * by iterating through it, thus leaving free units at the head of the
83 /** Constructs a circular queue of FU indices. */
88 /** Adds a FU to the queue. */
89 inline void addFU(int fu_idx);
91 /** Returns the index of the FU at the head of the queue, and changes
92 * the index to the next element.
97 /** Circular queue index. */
100 /** Size of the queue. */
103 /** Queue of FU indices. */
104 std::vector<int> funcUnitsIdx;
107 /** Per op class queues of FUs that provide that capability. */
108 FUIdxQueue fuPerCapList[Num_OpClasses];
110 /** Number of FUs. */
113 /** Functional units. */
114 std::vector<FuncUnit *> funcUnits;
116 typedef std::vector<FuncUnit *>::iterator fuListIterator;
119 typedef FUPoolParams Params;
120 /** Constructs a FU pool. */
121 FUPool(const Params *p);
124 /** Annotates units that provide memory operations. Included only because
125 * old FU pool provided this function.
127 void annotateMemoryUnits(Cycles hit_latency);
130 * Gets a FU providing the requested capability. Will mark the unit as busy,
131 * but leaves the freeing of the unit up to the IEW stage.
132 * @param capability The capability requested.
133 * @return Returns -2 if the FU pool does not have the capability, -1 if
134 * there is no free FU, and the FU's index otherwise.
136 int getUnit(OpClass capability);
138 /** Frees a FU at the end of this cycle. */
139 void freeUnitNextCycle(int fu_idx);
141 /** Frees all FUs on the list. */
142 void processFreeUnits();
144 /** Returns the total number of FUs. */
145 int size() { return numFU; }
147 /** Debugging function used to dump FU information. */
150 /** Returns the operation execution latency of the given capability. */
151 Cycles getOpLatency(OpClass capability) {
152 return maxOpLatencies[capability];
155 /** Returns the issue latency of the given capability. */
156 Cycles getIssueLatency(OpClass capability) {
157 return maxIssueLatencies[capability];
160 /** Switches out functional unit pool. */
163 /** Takes over from another CPU's thread. */
167 #endif // __CPU_O3_FU_POOL_HH__