cache.h

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/* Copyright (c) 2013 Wildfire Games
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef INCLUDED_X86_X64_CACHE
#define INCLUDED_X86_X64_CACHE

namespace x86_x64 {

struct Cache    // POD (may be used before static constructors)
{
    enum Type
    {
        // (values match the CPUID.4 definition)
        kNull,
        kData,
        kInstruction,
        kUnified
        // note: further values are "reserved"
    };

    static const size_t maxLevels = 4;

    static const size_t fullyAssociative = 0xFF;    // (CPUID.4 definition)

    /**
     * 1..maxLevels
     **/
    size_t level;

    /**
     * never kNull
     **/
    Type type;

    /**
     * if 0, the cache is disabled and all other values are zero
     **/
    size_t numEntries;

    /**
     * NB: cache entries are lines, TLB entries are pages
     **/
    size_t entrySize;

    /**
     * = fullyAssociative or the actual ways of associativity
     **/
    size_t associativity;

    /**
     * how many logical processors share this cache?
     **/
    size_t sharedBy;

    void Initialize(size_t level, Type type)
    {
        this->level   = level;
        this->type    = type;
        numEntries    = 0;
        entrySize     = 0;
        associativity = 0;
        sharedBy      = 0;

        ENSURE(Validate());
    }

    bool Validate() const
    {
        if(!(1 <= level && level <= maxLevels))
            return false;

        if(type == kNull)
            return false;

        if(numEntries == 0) // disabled
        {
            if(entrySize != 0)
                return false;
            if(associativity != 0)
                return false;
            if(sharedBy != 0)
                return false;
        }
        else
        {
            if(entrySize == 0)
                return false;
            if(associativity == 0 || associativity > fullyAssociative)
                return false;
            if(sharedBy == 0)
                return false;
        }

        return true;
    }

    u64 TotalSize() const
    {
        return u64(numEntries)*entrySize;
    }
};

enum IdxCache
{
    // (AddCache relies upon this order)
    L1D = 1,
    L2D,
    L3D,
    L4D,
    L1I,
    L2I,
    L3I,
    L4I,
    TLB
};

/**
 * @return 0 if idxCache >= TLB+numTLBs, otherwise a valid pointer to
 * a Cache whose numEntries is 0 if disabled / not present.
 **/
LIB_API const Cache* Caches(size_t idxCache);

}   // namespace x86_x64

#endif  // #ifndef INCLUDED_X86_X64_CACHE