along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include <cstring> // For std::memset
+#include "tt.h"
+
+#include <cassert>
+#include <cstdlib>
+#include <cstring>
#include <iostream>
#include <thread>
+#include <vector>
-#include "bitboard.h"
#include "misc.h"
#include "thread.h"
-#include "tt.h"
#include "uci.h"
namespace Stockfish {
-TranspositionTable TT; // Our global transposition table
-
-/// TTEntry::save() populates the TTEntry with a new node's data, possibly
-/// overwriting an old position. Update is not atomic and can be racy.
+TranspositionTable TT; // Our global transposition table
+// Populates the TTEntry with a new node's data, possibly
+// overwriting an old position. The update is not atomic and can be racy.
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 || (uint16_t)k != key16)
- move16 = (uint16_t)m;
-
- // Overwrite less valuable entries (cheapest checks first)
- if ( b == BOUND_EXACT
- || (uint16_t)k != key16
- || d - DEPTH_OFFSET + 2 * pv > depth8 - 4)
- {
- assert(d > DEPTH_OFFSET);
- assert(d < 256 + DEPTH_OFFSET);
-
- key16 = (uint16_t)k;
- depth8 = (uint8_t)(d - DEPTH_OFFSET);
- genBound8 = (uint8_t)(TT.generation8 | uint8_t(pv) << 2 | b);
- value16 = (int16_t)v;
- eval16 = (int16_t)ev;
- }
+ // Preserve any existing move for the same position
+ if (m || uint16_t(k) != key16)
+ move16 = uint16_t(m);
+
+ // Overwrite less valuable entries (cheapest checks first)
+ if (b == BOUND_EXACT || uint16_t(k) != key16 || d - DEPTH_OFFSET + 2 * pv > depth8 - 4)
+ {
+ assert(d > DEPTH_OFFSET);
+ assert(d < 256 + DEPTH_OFFSET);
+
+ key16 = uint16_t(k);
+ depth8 = uint8_t(d - DEPTH_OFFSET);
+ genBound8 = uint8_t(TT.generation8 | uint8_t(pv) << 2 | b);
+ value16 = int16_t(v);
+ eval16 = int16_t(ev);
+ }
}
-/// 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.
-
+// 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.
void TranspositionTable::resize(size_t mbSize) {
- Threads.main()->wait_for_search_finished();
+ Threads.main()->wait_for_search_finished();
- aligned_large_pages_free(table);
+ aligned_large_pages_free(table);
- clusterCount = mbSize * 1024 * 1024 / sizeof(Cluster);
+ clusterCount = mbSize * 1024 * 1024 / sizeof(Cluster);
- table = static_cast<Cluster*>(aligned_large_pages_alloc(clusterCount * sizeof(Cluster)));
- if (!table)
- {
- std::cerr << "Failed to allocate " << mbSize
- << "MB for transposition table." << std::endl;
- exit(EXIT_FAILURE);
- }
+ table = static_cast<Cluster*>(aligned_large_pages_alloc(clusterCount * sizeof(Cluster)));
+ if (!table)
+ {
+ std::cerr << "Failed to allocate " << mbSize << "MB for transposition table." << std::endl;
+ exit(EXIT_FAILURE);
+ }
- clear();
+ clear();
}
-/// TranspositionTable::clear() initializes the entire transposition table to zero,
-// in a multi-threaded way.
-
+// Initializes the entire transposition table to zero,
+// in a multi-threaded way.
void TranspositionTable::clear() {
- std::vector<std::thread> threads;
+ std::vector<std::thread> threads;
- for (size_t idx = 0; idx < size_t(Options["Threads"]); ++idx)
- {
- threads.emplace_back([this, idx]() {
+ for (size_t idx = 0; idx < size_t(Options["Threads"]); ++idx)
+ {
+ threads.emplace_back([this, idx]() {
+ // Thread binding gives faster search on systems with a first-touch policy
+ if (Options["Threads"] > 8)
+ WinProcGroup::bindThisThread(idx);
- // Thread binding gives faster search on systems with a first-touch policy
- if (Options["Threads"] > 8)
- WinProcGroup::bindThisThread(idx);
+ // Each thread will zero its part of the hash table
+ const size_t stride = size_t(clusterCount / Options["Threads"]),
+ start = size_t(stride * idx),
+ len =
+ idx != size_t(Options["Threads"]) - 1 ? stride : clusterCount - start;
- // Each thread will zero its part of the hash table
- const size_t stride = size_t(clusterCount / Options["Threads"]),
- start = size_t(stride * idx),
- len = idx != size_t(Options["Threads"]) - 1 ?
- stride : clusterCount - start;
+ std::memset(&table[start], 0, len * sizeof(Cluster));
+ });
+ }
- std::memset(&table[start], 0, len * sizeof(Cluster));
- });
- }
-
- for (std::thread& th : threads)
- th.join();
+ 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
-/// to be replaced later. The replace value of an entry is calculated as its depth
-/// minus 8 times its relative age. TTEntry t1 is considered more valuable than
-/// TTEntry t2 if its replace value is greater than that of t2.
-
+// 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
+// to be replaced later. The replace value of an entry is calculated as its depth
+// minus 8 times its relative age. TTEntry t1 is considered more valuable than
+// TTEntry t2 if its replace value is greater than that of t2.
TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
- TTEntry* const tte = first_entry(key);
- 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 == key16 || !tte[i].depth8)
- {
- tte[i].genBound8 = uint8_t(generation8 | (tte[i].genBound8 & (GENERATION_DELTA - 1))); // Refresh
-
- return found = (bool)tte[i].depth8, &tte[i];
- }
-
- // Find an entry to be replaced according to the replacement strategy
- TTEntry* replace = tte;
- for (int i = 1; i < ClusterSize; ++i)
- // Due to our packed storage format for generation and its cyclic
- // nature we add GENERATION_CYCLE (256 is the modulus, plus what
- // is needed to keep the unrelated lowest n bits from affecting
- // the result) to calculate the entry age correctly even after
- // generation8 overflows into the next cycle.
- if ( replace->depth8 - ((GENERATION_CYCLE + generation8 - replace->genBound8) & GENERATION_MASK)
- > tte[i].depth8 - ((GENERATION_CYCLE + generation8 - tte[i].genBound8) & GENERATION_MASK))
- replace = &tte[i];
-
- return found = false, replace;
+ TTEntry* const tte = first_entry(key);
+ 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 == key16 || !tte[i].depth8)
+ {
+ tte[i].genBound8 =
+ uint8_t(generation8 | (tte[i].genBound8 & (GENERATION_DELTA - 1))); // Refresh
+
+ return found = bool(tte[i].depth8), &tte[i];
+ }
+
+ // Find an entry to be replaced according to the replacement strategy
+ TTEntry* replace = tte;
+ for (int i = 1; i < ClusterSize; ++i)
+ // Due to our packed storage format for generation and its cyclic
+ // nature we add GENERATION_CYCLE (256 is the modulus, plus what
+ // is needed to keep the unrelated lowest n bits from affecting
+ // the result) to calculate the entry age correctly even after
+ // generation8 overflows into the next cycle.
+ if (replace->depth8
+ - ((GENERATION_CYCLE + generation8 - replace->genBound8) & GENERATION_MASK)
+ > tte[i].depth8
+ - ((GENERATION_CYCLE + generation8 - tte[i].genBound8) & GENERATION_MASK))
+ replace = &tte[i];
+
+ return found = false, replace;
}
-/// TranspositionTable::hashfull() returns an approximation of the hashtable
-/// occupation during a search. The hash is x permill full, as per UCI protocol.
+// Returns an approximation of the hashtable
+// occupation during a search. The hash is x permill full, as per UCI protocol.
int TranspositionTable::hashfull() const {
- int cnt = 0;
- for (int i = 0; i < 1000; ++i)
- for (int j = 0; j < ClusterSize; ++j)
- cnt += table[i].entry[j].depth8 && (table[i].entry[j].genBound8 & GENERATION_MASK) == generation8;
+ int cnt = 0;
+ for (int i = 0; i < 1000; ++i)
+ for (int j = 0; j < ClusterSize; ++j)
+ cnt += table[i].entry[j].depth8
+ && (table[i].entry[j].genBound8 & GENERATION_MASK) == generation8;
- return cnt / ClusterSize;
+ return cnt / ClusterSize;
}
-} // namespace Stockfish
+} // namespace Stockfish
projects / stockfish / blobdiff