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28 * Authors: Daniel Carvalho
33 * Declaration of a Least Recently Used replacement policy.
34 * The victim is chosen using the timestamp. The timestamp may be true or
35 * pseudo, depending on the quantity of bits allocated for that.
38 #ifndef __MEM_CACHE_REPLACEMENT_POLICIES_LRU_RP_HH__
39 #define __MEM_CACHE_REPLACEMENT_POLICIES_LRU_RP_HH__
41 #include "mem/cache/replacement_policies/base.hh"
45 class LRURP : public BaseReplacementPolicy
48 /** LRU-specific implementation of replacement data. */
49 struct LRUReplData : ReplacementData
51 /** Tick on which the entry was last touched. */
55 * Default constructor. Invalidate data.
57 LRUReplData() : lastTouchTick(0) {}
61 /** Convenience typedef. */
62 typedef LRURPParams Params;
65 * Construct and initiliaze this replacement policy.
67 LRURP(const Params *p);
75 * Invalidate replacement data to set it as the next probable victim.
76 * Sets its last touch tick as the starting tick.
78 * @param replacement_data Replacement data to be invalidated.
80 void invalidate(const std::shared_ptr<ReplacementData>& replacement_data)
84 * Touch an entry to update its replacement data.
85 * Sets its last touch tick as the current tick.
87 * @param replacement_data Replacement data to be touched.
89 void touch(const std::shared_ptr<ReplacementData>& replacement_data) const
93 * Reset replacement data. Used when an entry is inserted.
94 * Sets its last touch tick as the current tick.
96 * @param replacement_data Replacement data to be reset.
98 void reset(const std::shared_ptr<ReplacementData>& replacement_data) const
102 * Find replacement victim using LRU timestamps.
104 * @param candidates Replacement candidates, selected by indexing policy.
105 * @return Replacement entry to be replaced.
107 ReplaceableEntry* getVictim(const ReplacementCandidates& candidates) const
111 * Instantiate a replacement data entry.
113 * @return A shared pointer to the new replacement data.
115 std::shared_ptr<ReplacementData> instantiateEntry() override;
118 #endif // __MEM_CACHE_REPLACEMENT_POLICIES_LRU_RP_HH__