2cc2ad5097
Add a generic cache library modeled after AssociativeSet that can be used for constructing internal caching structures. Change-Id: I1767309ed01f52672b32810636a09142ff23242f
137 lines
3.8 KiB
C++
137 lines
3.8 KiB
C++
/**
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* Copyright (c) 2024 - Pranith Kumar
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* Copyright (c) 2020 Inria
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __BASE_CACHE_CACHE_ENTRY_HH__
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#define __BASE_CACHE_CACHE_ENTRY_HH__
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#include <cassert>
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#include "base/cprintf.hh"
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#include "base/types.hh"
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#include "mem/cache/replacement_policies/replaceable_entry.hh"
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namespace gem5
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{
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/**
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* A CacheEntry is an entry containing a tag. A tagged entry's contents
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* are only relevant if it is marked as valid.
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*/
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class CacheEntry : public ReplaceableEntry
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{
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public:
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CacheEntry() = default;
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~CacheEntry() = default;
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/**
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* Checks if the entry is valid.
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*
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* @return True if the entry is valid.
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*/
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virtual bool isValid() const { return valid; }
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/**
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* Get tag associated to this block.
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*
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* @return The tag value.
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*/
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virtual Addr getTag() const { return tag; }
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/**
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* Checks if the given tag information corresponds to this entry's.
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*
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* @param tag The tag value to compare to.
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* @return True if the tag information match this entry's.
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*/
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virtual bool
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matchTag(const Addr tag) const
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{
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return isValid() && (getTag() == tag);
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}
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/**
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* Insert the block by assigning it a tag and marking it valid. Touches
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* block if it hadn't been touched previously.
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*
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* @param tag The tag value.
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*/
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virtual void
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insert(const Addr tag)
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{
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setValid();
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setTag(tag);
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}
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/** Invalidate the block. Its contents are no longer valid. */
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virtual void
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invalidate()
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{
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valid = false;
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setTag(MaxAddr);
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}
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std::string
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print() const override
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{
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return csprintf("tag: %#x valid: %d | %s", getTag(),
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isValid(), ReplaceableEntry::print());
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}
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protected:
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/**
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* Set tag associated to this block.
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*
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* @param tag The tag value.
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*/
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virtual void setTag(Addr _tag) { tag = _tag; }
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/** Set valid bit. The block must be invalid beforehand. */
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virtual void
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setValid()
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{
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assert(!isValid());
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valid = true;
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}
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private:
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/**
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* Valid bit. The contents of this entry are only valid if this bit is set.
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* @sa invalidate()
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* @sa insert()
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*/
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bool valid{false};
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/** The entry's tag. */
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Addr tag{MaxAddr};
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};
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} // namespace gem5
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#endif //__CACHE_ENTRY_HH__
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