#include "misc.h"
#include "types.h"
-/// The TTEntry is the 128 bit transposition table entry, defined as below:
+/// The TTEntry is the 10 bytes transposition table entry, defined as below:
///
-/// key: 32 bit
-/// move: 16 bit
-/// bound type: 8 bit
-/// generation: 8 bit
-/// value: 16 bit
-/// depth: 16 bit
-/// static value: 16 bit
+/// key 16 bit
+/// move 16 bit
+/// value 16 bit
+/// eval value 16 bit
+/// generation 6 bit
+/// bound type 2 bit
+/// depth 8 bit
struct TTEntry {
- void save(uint32_t k, Value v, Bound b, Depth d, Move m, int 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;
- }
-
- uint32_t key() const { return key32; }
- Move move() const { return (Move)move16; }
- Bound bound() const { return (Bound)bound8; }
+ Move move() const { return (Move )move16; }
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; }
+ Bound bound() const { return (Bound)(genBound8 & 0x3); }
private:
- friend struct TranspositionTable;
+ friend class TranspositionTable;
+
+ void save(uint16_t k, Value v, Bound b, Depth d, Move m, uint8_t g, Value ev) {
+
+ key16 = (uint16_t)k;
+ move16 = (uint16_t)m;
+ value16 = (int16_t)v;
+ evalValue = (int16_t)ev;
+ genBound8 = (uint8_t)(g | b);
+ depth8 = (int8_t)d;
+ }
- 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;
+ int8_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; // A cluster is 64 Bytes
-
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 resize(uint64_t mbSize);
+ void resize(size_t mbSize);
void clear();
void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
private:
- uint32_t hashMask;
- TTEntry* table;
+ size_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[(size_t)key & (clusterCount - 1)].entry[0];
}
#endif // #ifndef TT_H_INCLUDED