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Diffstat (limited to 'src/mem/cache/prefetch/associative_set.hh')
| -rw-r--r-- | src/mem/cache/prefetch/associative_set.hh | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/src/mem/cache/prefetch/associative_set.hh b/src/mem/cache/prefetch/associative_set.hh new file mode 100644 index 000000000..99b6a6d07 --- /dev/null +++ b/src/mem/cache/prefetch/associative_set.hh @@ -0,0 +1,200 @@ +/** + * Copyright (c) 2018 Metempsy Technology Consulting + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Javier Bueno + */ + +#ifndef __CACHE_PREFETCH_ASSOCIATIVE_SET_HH__ +#define __CACHE_PREFETCH_ASSOCIATIVE_SET_HH__ + +#include "mem/cache/replacement_policies/base.hh" +#include "mem/cache/replacement_policies/replaceable_entry.hh" +#include "mem/cache/tags/indexing_policies/base.hh" + +/** + * Entry used for set-associative tables, usable with replacement policies + */ +class TaggedEntry : public ReplaceableEntry { + /** Tag for the entry */ + Addr tag; + /** Valid bit */ + bool valid; + /** Whether this entry refers to a memory area in the secure space */ + bool secure; + public: + TaggedEntry() : tag(0), valid(false), secure(false) {} + virtual ~TaggedEntry() {} + + /** + * Consult the valid bit + * @return True if the entry is valid + */ + bool isValid() const + { + return valid; + } + + /** + * Sets the entry to valid + */ + void setValid() + { + valid = true; + } + + /** + * Sets the entry to invalid + */ + void setInvalid() { + valid = false; + } + + /** + * Obtain the entry tag + * @return the tag value + */ + Addr getTag() const + { + return tag; + } + + /** + * Sets the tag of the entry + * @param t the tag value + */ + void setTag(Addr t) + { + tag = t; + } + + /** + * Consult if this entry refers to a memory in the secure area + * @return True if this entry refers to secure memory area + */ + bool isSecure() const + { + return secure; + } + + /** + * Sets the secure value bit + * @param s secure bit value + */ + void setSecure(bool s) + { + secure = s; + } + + /** + * Resets the entry, this is called when an entry is evicted to allocate + * a new one. Types inheriting this class should provide its own + * implementation + */ + virtual void reset () { + } +}; + +/** + * Associative container based on the previosuly defined Entry type + * Each element is indexed by a key of type Addr, an additional + * bool value is used as an additional tag data of the entry. + */ +template<class Entry> +class AssociativeSet { + static_assert(std::is_base_of<TaggedEntry, Entry>::value, + "Entry must derive from TaggedEntry"); + + /** Associativity of the container */ + const int associativity; + /** + * Total number of entries, entries are organized in sets of the provided + * associativity. The number of associative sets is obtained by dividing + * numEntries by associativity. + */ + const int numEntries; + /** Pointer to the indexing policy */ + BaseIndexingPolicy* const indexingPolicy; + /** Pointer to the replacement policy */ + BaseReplacementPolicy* const replacementPolicy; + /** Vector containing the entries of the container */ + std::vector<Entry> entries; + + public: + /** + * Public constructor + * @param assoc number of elements in each associative set + * @param num_entries total number of entries of the container, the number + * of sets can be calculated dividing this balue by the 'assoc' value + * @param idx_policy indexing policy + * @param rpl_policy replacement policy + * @param initial value of the elements of the set + */ + AssociativeSet(int assoc, int num_entries, BaseIndexingPolicy *idx_policy, + BaseReplacementPolicy *rpl_policy, Entry const &init_value = + Entry()); + + /** + * Find an entry within the set + * @param addr key element + * @param is_secure tag element + * @return returns a pointer to the wanted entry or nullptr if it does not + * exist. + */ + Entry* findEntry(Addr addr, bool is_secure) const; + + /** + * Do an access to the entry, this is required to + * update the replacement information data. + * @param entry the accessed entry + */ + void accessEntry(Entry *entry); + + /** + * Find a victim to be replaced + * @param addr key to select the possible victim + * @result entry to be victimized + */ + Entry* findVictim(Addr addr); + + /** + * Find the set of entries that could be replaced given + * that we want to add a new entry with the provided key + * @param addr key to select the set of entries + * @result vector of candidates matching with the provided key + */ + std::vector<Entry *> getPossibleEntries(const Addr addr) const; + + /** + * Indicate that an entry has just been inserted + * @param addr key of the container + * @param is_secure tag component of the container + * @param entry pointer to the container entry to be inserted + */ + void insertEntry(Addr addr, bool is_secure, Entry* entry); +}; + +#endif//__CACHE_PREFETCH_ASSOCIATIVE_SET_HH__ |