/// TranspositionTable::resize() sets the size of the transposition table,
/// measured in megabytes. Transposition table consists of a power of 2 number
-/// of clusters and each cluster consists of ClusterSize number of TTEntry.
+/// of clusters and each cluster consists of TTClusterSize number of TTEntry.
void TranspositionTable::resize(uint64_t mbSize) {
- assert(msb((mbSize << 20) / sizeof(TTEntry)) < 32);
+ assert(msb((mbSize * 1024 * 1024) / sizeof(TTCluster)) < 32);
- uint32_t size = ClusterSize << msb((mbSize << 20) / sizeof(TTEntry[ClusterSize]));
+ uint32_t newClusterCount = 1 << msb((mbSize * 1024 * 1024) / sizeof(TTCluster));
- if (hashMask == size - ClusterSize)
+ if (newClusterCount == clusterCount)
return;
- hashMask = size - ClusterSize;
+ clusterCount = newClusterCount;
+
free(mem);
- mem = calloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1, 1);
+ mem = calloc(clusterCount * sizeof(TTCluster) + CACHE_LINE_SIZE - 1, 1);
if (!mem)
{
exit(EXIT_FAILURE);
}
- table = (TTEntry*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
+ table = (TTCluster*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
}
void TranspositionTable::clear() {
- std::memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
+ std::memset(table, 0, clusterCount * sizeof(TTCluster));
}
const TTEntry* TranspositionTable::probe(const Key key) const {
TTEntry* tte = first_entry(key);
- uint32_t key32 = key >> 32;
+ uint16_t key16 = key >> 48;
- for (unsigned i = 0; i < ClusterSize; ++i, ++tte)
- if (tte->key32 == key32)
+ for (unsigned i = 0; i < TTClusterSize; ++i, ++tte)
+ if (tte->key16 == key16)
{
- tte->generation8 = generation; // Refresh
+ tte->genBound8 = generation | tte->bound(); // Refresh
return tte;
}
void TranspositionTable::store(const Key key, Value v, Bound b, Depth d, Move m, Value statV) {
TTEntry *tte, *replace;
- uint32_t key32 = key >> 32; // Use the high 32 bits as key inside the cluster
+ uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
tte = replace = first_entry(key);
- for (unsigned i = 0; i < ClusterSize; ++i, ++tte)
+ for (unsigned i = 0; i < TTClusterSize; ++i, ++tte)
{
- if (!tte->key32 || tte->key32 == key32) // Empty or overwrite old
+ if (!tte->key16 || tte->key16 == key16) // Empty or overwrite old
{
if (!m)
m = tte->move(); // Preserve any existing ttMove
}
// Implement replace strategy
- if ( ( tte->generation8 == generation || tte->bound() == BOUND_EXACT)
- - (replace->generation8 == generation)
- - (tte->depth16 < replace->depth16) < 0)
+ if ( (( tte->genBound8 & 0xFC) == generation || tte->bound() == BOUND_EXACT)
+ - ((replace->genBound8 & 0xFC) == generation)
+ - (tte->depth8 < replace->depth8) < 0)
replace = tte;
}
- replace->save(key32, v, b, d, m, generation, statV);
+ replace->save(key16, v, b, d, m, generation, statV);
}
#include "misc.h"
#include "types.h"
-/// The TTEntry is the 14 bytes transposition table entry, defined as below:
+/// The TTEntry is the 10 bytes transposition table entry, defined as below:
///
-/// key 32 bit
+/// key 16 bit
/// move 16 bit
-/// bound type 8 bit
-/// generation 8 bit
/// value 16 bit
-/// depth 16 bit
/// eval value 16 bit
+/// generation 6 bit
+/// bound type 2 bit
+/// depth 8 bit
struct TTEntry {
Move move() const { return (Move )move16; }
- Bound bound() const { return (Bound)bound8; }
Value value() const { return (Value)value16; }
- Depth depth() const { return (Depth)depth16; }
Value eval_value() const { return (Value)evalValue; }
+ Depth depth() const { return (Depth)(depth8) + DEPTH_NONE; }
+ Bound bound() const { return (Bound)(genBound8 & 0x3); }
private:
friend class TranspositionTable;
- void save(uint32_t k, Value v, Bound b, Depth d, Move m, uint8_t g, Value ev) {
+ void save(uint16_t k, Value v, Bound b, Depth d, Move m, uint8_t g, Value ev) {
- key32 = (uint32_t)k;
- move16 = (uint16_t)m;
- bound8 = (uint8_t)b;
- generation8 = (uint8_t)g;
- value16 = (int16_t)v;
- depth16 = (int16_t)d;
- evalValue = (int16_t)ev;
+ key16 = (uint16_t)k;
+ move16 = (uint16_t)m;
+ value16 = (int16_t)v;
+ evalValue = (int16_t)ev;
+ depth8 = (uint8_t)(d - DEPTH_NONE);
+ genBound8 = g | (uint8_t)b;
}
- uint32_t key32;
+ uint16_t key16;
uint16_t move16;
- uint8_t bound8, generation8;
- int16_t value16, depth16, evalValue;
+ int16_t value16;
+ int16_t evalValue;
+ uint8_t genBound8;
+ uint8_t depth8;
};
+/// TTCluster is a 32 bytes cluster of TT entries consisting of:
+///
+/// 3 x TTEntry (3 x 10 bytes)
+/// padding (2 bytes)
+
+const unsigned TTClusterSize = 3;
+
+struct TTCluster {
+
+ TTEntry entry[TTClusterSize];
+ char padding[2];
+};
/// A TranspositionTable consists of a power of 2 number of clusters and each
-/// cluster consists of ClusterSize number of TTEntry. Each non-empty entry
+/// cluster consists of TTClusterSize number of TTEntry. Each non-empty entry
/// contains information of exactly one position. The size of a cluster should
/// not be bigger than a cache line size. In case it is less, it should be padded
/// to guarantee always aligned accesses.
class TranspositionTable {
- static const unsigned ClusterSize = 4;
-
public:
~TranspositionTable() { free(mem); }
- void new_search() { ++generation; }
+ void new_search() { generation += 4; } // Lower 2 bits are used by Bound
const TTEntry* probe(const Key key) const;
TTEntry* first_entry(const Key key) const;
void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
private:
- uint32_t hashMask;
- TTEntry* table;
+ uint32_t clusterCount;
+ TTCluster* table;
void* mem;
- uint8_t generation; // Size must be not bigger than TTEntry::generation8
+ uint8_t generation; // Size must be not bigger than TTEntry::genBound8
};
extern TranspositionTable TT;
/// TranspositionTable::first_entry() returns a pointer to the first entry of
/// a cluster given a position. The lowest order bits of the key are used to
-/// get the index of the cluster.
+/// get the index of the cluster inside the table.
inline TTEntry* TranspositionTable::first_entry(const Key key) const {
- return table + ((uint32_t)key & hashMask);
+ return &table[(uint32_t)key & (clusterCount - 1)].entry[0];
}
#endif // #ifndef TT_H_INCLUDED
DEPTH_QS_NO_CHECKS = -1 * ONE_PLY,
DEPTH_QS_RECAPTURES = -5 * ONE_PLY,
- DEPTH_NONE = -127 * ONE_PLY
+ DEPTH_NONE = -6 * ONE_PLY
};
enum Square {
projects / stockfish / commitdiff