Set associative cache simulation with LRU

Question

So basically this is a set associative cache simulation. I need to get it working for 2,4,16 and 32 way associative caches. The LRU is a series of deques within a vector, and the cache itself is a vector of longlongs where the least significant bit is the valid bit. I keep getting a few thousand or so less hits than I should be. Testing on 1122102 instructions with target addresses. Just want to know if there's any errors I'm overlooking here.

bool setA(string behavior, int asc, unsigned long long target,  vector<unsigned long long>& cache, vector<deque<int>>& lru){
    bool hit=false;
    int kb=16;
    const int line_size_bytes = 32;
    const int num_cache_lines = (kb * 1024) / line_size_bytes;
    const int num_sets = num_cache_lines / asc;
    
    unsigned long long index = (target / line_size_bytes) % num_sets;
    unsigned long long tag = target / (line_size_bytes * num_sets);

    int start_index = index * asc;
   int end_index = start_index + asc;
    
    auto it = find_if(cache.begin() + start_index, cache.begin() + end_index, [&tag](unsigned long long line) { return line & 1 && (line >> 1) == tag; });
    if (it != cache.begin() + end_index) {
        // Cache hit
        hit = true;
        int position = distance(cache.begin()+start_index, it);

        // Update LRU: Move the cache line to the end of the deque
        auto lru_it = find(lru[index].begin(), lru[index].end(), position);
        lru[index].erase(lru_it);
        lru[index].push_back(position);
    } else {
        // Cache miss
        // Find the least recently used cache line in the set
        int lru_position = lru[index].front();
        lru[index].pop_front();

        // Replace the least recently used cache line with the new tag and valid bit
        cache[start_index + lru_position] = (tag << 1) | 1;

        // update newly used line with used line
        lru[index].push_back(lru_position);
    }
    
    return hit;
}