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41 * Authors: Ron Dreslinski
47 * Describes a strided prefetcher.
50 #ifndef __MEM_CACHE_PREFETCH_STRIDE_HH__
51 #define __MEM_CACHE_PREFETCH_STRIDE_HH__
54 #include <unordered_map>
57 #include "base/types.hh"
58 #include "mem/cache/prefetch/queued.hh"
59 #include "mem/cache/replacement_policies/replaceable_entry.hh"
60 #include "mem/packet.hh"
62 class BaseReplacementPolicy;
63 struct StridePrefetcherParams;
65 class StridePrefetcher : public QueuedPrefetcher
73 const int pcTableAssoc;
74 const int pcTableSets;
76 const bool useMasterId;
80 /** Replacement policy used in the PC tables. */
81 BaseReplacementPolicy* replacementPolicy;
83 struct StrideEntry : public ReplaceableEntry
85 /** Default constructor */
88 /** Invalidate the entry */
102 * Default constructor. Create a table with given parameters.
104 * @param assoc Associativity of the table.
105 * @param sets Number of sets in the table.
106 * @param name Name of the prefetcher.
107 * @param replacementPolicy Replacement policy used by the table.
109 PCTable(int assoc, int sets, const std::string name,
110 BaseReplacementPolicy* replacementPolicy);
113 * Default destructor.
118 * Search for an entry in the pc table.
120 * @param pc The PC to look for.
121 * @param is_secure True if the target memory space is secure.
122 * @return Pointer to the entry.
124 StrideEntry* findEntry(Addr pc, bool is_secure);
127 * Find a replacement victim to make room for given PC.
129 * @param pc The PC value.
130 * @return The victimized entry.
132 StrideEntry* findVictim(Addr pc);
135 const std::string name() {return _name; }
136 const int pcTableSets;
137 const std::string _name;
138 std::vector<std::vector<StrideEntry>> entries;
141 * Replacement policy used by StridePrefetcher.
143 BaseReplacementPolicy* replacementPolicy;
146 * PC hashing function to index sets in the table.
148 * @param pc The PC value.
149 * @return The set to which this PC maps.
151 Addr pcHash(Addr pc) const;
153 std::unordered_map<int, PCTable> pcTables;
156 * Try to find a table of entries for the given context. If none is
157 * found, a new table is created.
159 * @param context The context to be searched for.
160 * @return The table corresponding to the given context.
162 PCTable* findTable(int context);
165 * Create a PC table for the given context.
167 * @param context The context of the new PC table.
168 * @return The new PC table
170 PCTable* allocateNewContext(int context);
173 StridePrefetcher(const StridePrefetcherParams *p);
175 void calculatePrefetch(const PrefetchInfo &pfi,
176 std::vector<AddrPriority> &addresses) override;
179 #endif // __MEM_CACHE_PREFETCH_STRIDE_HH__