cacheset.hh

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 * Authors: Lisa Hsu
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#ifndef __MEM_CACHE_TAGS_CACHESET_HH__
#define __MEM_CACHE_TAGS_CACHESET_HH__

#include <cassert>

template <class Blktype>
class CacheSet
{
  public:
    int assoc;

    Blktype **blks;

    Blktype* findBlk(Addr tag, bool is_secure, int& way_id) const ;
    Blktype* findBlk(Addr tag, bool is_secure) const ;

    void moveToHead(Blktype *blk);

    void moveToTail(Blktype *blk);

};

template <class Blktype>
Blktype*
CacheSet<Blktype>::findBlk(Addr tag, bool is_secure, int& way_id) const
{
    way_id = assoc;
    for (int i = 0; i < assoc; ++i) {
        if (blks[i]->tag == tag && blks[i]->isValid() &&
            blks[i]->isSecure() == is_secure) {
            way_id = i;
            return blks[i];
        }
    }
    return nullptr;
}

template <class Blktype>
Blktype*
CacheSet<Blktype>::findBlk(Addr tag, bool is_secure) const
{
    int ignored_way_id;
    return findBlk(tag, is_secure, ignored_way_id);
}

template <class Blktype>
void
CacheSet<Blktype>::moveToHead(Blktype *blk)
{
    // nothing to do if blk is already head
    if (blks[0] == blk)
        return;

    // write 'next' block into blks[i], moving up from MRU toward LRU
    // until we overwrite the block we moved to head.

    // start by setting up to write 'blk' into blks[0]
    int i = 0;
    Blktype *next = blk;

    do {
        assert(i < assoc);
        std::swap(blks[i], next);
        ++i;
    } while (next != blk);
}

template <class Blktype>
void
CacheSet<Blktype>::moveToTail(Blktype *blk)
{
    // nothing to do if blk is already tail
    if (blks[assoc - 1] == blk)
        return;

    // write 'next' block into blks[i], moving from LRU to MRU
    // until we overwrite the block we moved to tail.

    // start by setting up to write 'blk' into tail
    int i = assoc - 1;
    Blktype *next = blk;

    do {
        assert(i >= 0);
        std::swap(blks[i], next);
        --i;
    } while (next != blk);
}

#endif