/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
TranspositionTable TT; // Our global transposition table
-/// TTEntry::save saves a TTEntry
-void TTEntry::save(Key k, Value v, bool PvNode, Bound b, Depth d, Move m, Value ev) {
+/// TTEntry::save() populates the TTEntry with a new node's data, possibly
+/// overwriting an old position. Update is not atomic and can be racy.
- assert(d / ONE_PLY * ONE_PLY == d);
+void TTEntry::save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev) {
// Preserve any existing move for the same position
- if (m || (k >> 48) != key16)
+ if (m || (uint16_t)k != key16)
move16 = (uint16_t)m;
// Overwrite less valuable entries
- if ( (k >> 48) != key16
- || d / ONE_PLY > depth8 - 4
+ if ((uint16_t)k != key16
+ || d - DEPTH_OFFSET > depth8 - 4
|| b == BOUND_EXACT)
{
- key16 = (uint16_t)(k >> 48);
+ assert(d >= DEPTH_OFFSET);
+
+ key16 = (uint16_t)k;
value16 = (int16_t)v;
eval16 = (int16_t)ev;
- genBound8 = (uint8_t)(TT.generation8 | PvNode << 2 | b);
- depth8 = (int8_t)(d / ONE_PLY);
+ genBound8 = (uint8_t)(TT.generation8 | uint8_t(pv) << 2 | b);
+ depth8 = (uint8_t)(d - DEPTH_OFFSET);
}
}
Threads.main()->wait_for_search_finished();
- clusterCount = mbSize * 1024 * 1024 / sizeof(Cluster);
-
- free(mem);
- mem = malloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1);
+ aligned_ttmem_free(mem);
+ clusterCount = mbSize * 1024 * 1024 / sizeof(Cluster);
+ table = static_cast<Cluster*>(aligned_ttmem_alloc(clusterCount * sizeof(Cluster), mem));
if (!mem)
{
std::cerr << "Failed to allocate " << mbSize
exit(EXIT_FAILURE);
}
- table = (Cluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1));
clear();
}
WinProcGroup::bindThisThread(idx);
// Each thread will zero its part of the hash table
- const size_t stride = clusterCount / Options["Threads"],
- start = stride * idx,
+ const size_t stride = size_t(clusterCount / Options["Threads"]),
+ start = size_t(stride * idx),
len = idx != Options["Threads"] - 1 ?
stride : clusterCount - start;
});
}
- for (std::thread& th: threads)
+ for (std::thread& th : threads)
th.join();
}
+
/// TranspositionTable::probe() looks up the current position in the transposition
/// table. It returns true and a pointer to the TTEntry if the position is found.
/// Otherwise, it returns false and a pointer to an empty or least valuable TTEntry
TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
TTEntry* const tte = first_entry(key);
- const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
+ const uint16_t key16 = (uint16_t)key; // Use the low 16 bits as key inside the cluster
for (int i = 0; i < ClusterSize; ++i)
if (!tte[i].key16 || tte[i].key16 == key16)
{
- tte[i].genBound8 = uint8_t(generation8 | tte[i].pv_hit() << 2 | tte[i].bound()); // Refresh
+ tte[i].genBound8 = uint8_t(generation8 | (tte[i].genBound8 & 0x7)); // Refresh
return found = (bool)tte[i].key16, &tte[i];
}
TTEntry* replace = tte;
for (int i = 1; i < ClusterSize; ++i)
// Due to our packed storage format for generation and its cyclic
- // nature we add 263 (263 is the modulus plus 7 to keep the lowest
- // two bound bits from affecting the result) to calculate the entry
+ // nature we add 263 (256 is the modulus plus 7 to keep the unrelated
+ // lowest three bits from affecting the result) to calculate the entry
// age correctly even after generation8 overflows into the next cycle.
if ( replace->depth8 - ((263 + generation8 - replace->genBound8) & 0xF8)
> tte[i].depth8 - ((263 + generation8 - tte[i].genBound8) & 0xF8))
int TranspositionTable::hashfull() const {
int cnt = 0;
- for (int i = 0; i < 1000 / ClusterSize; ++i)
+ for (int i = 0; i < 1000; ++i)
for (int j = 0; j < ClusterSize; ++j)
- cnt += (table[i].entry[j].genBound8 & 0xFC) == generation8;
+ cnt += (table[i].entry[j].genBound8 & 0xF8) == generation8;
- return cnt * 1000 / (ClusterSize * (1000 / ClusterSize));
+ return cnt / ClusterSize;
}