HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-23 10:36:26 +08:00
Code Issues Packages Projects Releases Wiki Activity

Document TT code more

Browse Source 
Slight refactor of the TT code with the goal to make it easier to understand / tweak.

Passed Non-Regression STC:
https://tests.stockfishchess.org/tests/view/65d51e401d8e83c78bfdc427
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 56416 W: 14750 L: 14550 D: 27116
Ptnml(0-2): 227, 6386, 14796, 6558, 241

closes https://github.com/official-stockfish/Stockfish/pull/5061

No functional change
This commit is contained in:
Disservin
2024-02-20 22:47:26 +01:00
committed by Joost VandeVondele
parent f77eddfa2f
commit 0a3eb1d8fa
2 changed files with 38 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
src/tt.h
View File

@@ -46,6 +46,8 @@ struct TTEntry {
bool is_pv() const { return bool(genBound8 & 0x4); }
Bound bound() const { return Bound(genBound8 & 0x3); }
void save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev, uint8_t generation8);
// The returned age is a multiple of TranspositionTable::GENERATION_DELTA
uint8_t relative_age(const uint8_t generation8) const;
private:
friend class TranspositionTable;
@@ -76,16 +78,25 @@ class TranspositionTable {
static_assert(sizeof(Cluster) == 32, "Unexpected Cluster size");
// Constants used to refresh the hash table periodically
static constexpr unsigned GENERATION_BITS = 3; // nb of bits reserved for other things
static constexpr int GENERATION_DELTA =
(1 << GENERATION_BITS); // increment for generation field
static constexpr int GENERATION_CYCLE = 255 + (1 << GENERATION_BITS); // cycle length
static constexpr int GENERATION_MASK =
(0xFF << GENERATION_BITS) & 0xFF; // mask to pull out generation number
// We have 8 bits available where the lowest 3 bits are
// reserved for other things.
static constexpr unsigned GENERATION_BITS = 3;
// increment for generation field
static constexpr int GENERATION_DELTA = (1 << GENERATION_BITS);
// cycle length
static constexpr int GENERATION_CYCLE = 255 + GENERATION_DELTA;
// mask to pull out generation number
static constexpr int GENERATION_MASK = (0xFF << GENERATION_BITS) & 0xFF;
public:
~TranspositionTable() { aligned_large_pages_free(table); }
void new_search() { generation8 += GENERATION_DELTA; } // Lower bits are used for other things
void new_search() {
// increment by delta to keep lower bits as is
generation8 += GENERATION_DELTA;
}
TTEntry* probe(const Key key, bool& found) const;
int hashfull() const;
void resize(size_t mbSize, int threadCount);