uint64_t hash, chess::Move best, Stockfish::Value score, int8_t depth, TTFlag flag) {

// 2 entries per bucket

if (buckets == 0)

return;

uint64_t index = (hash & (buckets - 1)) * 2;

TTEntry &e0 = table[index], &e1 = table[index + 1];

// Store the entry

// Store the entry

TTEntry* replace = &e0; // Default to first entry

for (TTEntry* e : {&e0, &e1})

{

if (e->hash == hash)

{

// Always replace exact hash match

e->set(depth, flag, score, best);

return;

}

if (e->depth < depth)

{

// Prefer entry with lower depth

replace = e;

break;

}

if (e->depth < replace->depth)

{

// Among candidates, choose the one with lowest depth

replace = e;

}

}

replace->hash = hash;

replace->set(depth, flag, score, best);

size_t count = 0;

// Unroll loop for speed (process 4 entries per iteration)

size_t i = 0;

size_t limit = size & ~3ULL; // align to multiple of 4

for (; i < limit; i += 4)

{

count += (table[i].hash != 0);

count += (table[i + 1].hash != 0);

count += (table[i + 2].hash != 0);

count += (table[i + 3].hash != 0);

}

for (; i < size; ++i)

{

count += (table[i].hash != 0);

}

return static_cast<int>((count * 1000) / size);