#include "movegen.h"
#include "tt.h"
-
-/// This is the number of TTEntry slots for each position
-static const int ClusterSize = 5;
-
+// The main transposition table
+TranspositionTable TT;
////
//// Functions
void TranspositionTable::set_size(unsigned mbSize) {
- assert(mbSize >= 4 && mbSize <= 4096);
+ assert(mbSize >= 4 && mbSize <= 2048);
unsigned newSize = 1024;
// We store a cluster of ClusterSize number of TTEntry for each position
// and newSize is the maximum number of storable positions.
- while ((2 * newSize) * ClusterSize * (sizeof(TTEntry)) <= (mbSize << 20))
+ while ((2 * newSize) * sizeof(TTCluster) <= (mbSize << 20))
newSize *= 2;
if (newSize != size)
{
size = newSize;
delete [] entries;
- entries = new TTEntry[size * ClusterSize];
+ entries = new TTCluster[size];
if (!entries)
{
std::cerr << "Failed to allocate " << mbSize
void TranspositionTable::clear() {
- memset(entries, 0, size * ClusterSize * sizeof(TTEntry));
+ memset(entries, 0, size * sizeof(TTCluster));
}
inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
- return entries + ((uint32_t(posKey) & (size - 1)) * ClusterSize);
+ return entries[uint32_t(posKey) & (size - 1)].data;
}
{
if (!tte->key() || tte->key() == posKey32) // empty or overwrite old
{
- // Do not overwrite when new type is VALUE_TYPE_EVAL
- if (tte->key() && t == VALUE_TYPE_EVAL)
+ // Do not overwrite when new type is VALUE_TYPE_EV_LO
+ if (tte->key() && t == VALUE_TYPE_EV_LO)
return;
if (m == MOVE_NONE)
/// blocking function and do not stalls the CPU waiting for data
/// to be loaded from RAM, that can be very slow. When we will
/// subsequently call retrieve() the TT data will be already
-/// quickly accessible in L1/l2 CPU cache.
+/// quickly accessible in L1/L2 CPU cache.
void TranspositionTable::prefetch(const Key posKey) const {
- _mm_prefetch((char*)first_entry(posKey), _MM_HINT_T0);
+#if defined(__INTEL_COMPILER) || defined(__ICL)
+ // This hack prevents prefetches to be optimized away by the
+ // Intel compiler. Both MSVC and gcc seems not affected.
+ __asm__ ("");
+#endif
+
+ char const* addr = (char*)first_entry(posKey);
+ _mm_prefetch(addr, _MM_HINT_T2);
+ _mm_prefetch(addr+64, _MM_HINT_T2); // 64 bytes ahead
}
for (int i = 0; pv[i] != MOVE_NONE; i++)
{
- store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
+ TTEntry *tte = retrieve(p.get_key());
+ if (!tte || tte->move() != pv[i])
+ store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
p.do_move(pv[i], st);
}
}
/// will often get single-move PVs when the search stops while failing high,
/// and a single-move PV means that we don't have a ponder move.
-void TranspositionTable::extract_pv(const Position& pos, Move pv[]) {
-
- int ply;
- Position p(pos);
- StateInfo st[100];
-
- for (ply = 0; pv[ply] != MOVE_NONE; ply++)
- p.do_move(pv[ply], st[ply]);
+void TranspositionTable::extract_pv(const Position& pos, Move pv[], const int PLY_MAX) {
- bool stop;
const TTEntry* tte;
- for (stop = false, tte = retrieve(p.get_key());
- tte && tte->move() != MOVE_NONE && !stop;
- tte = retrieve(p.get_key()), ply++)
+ StateInfo st;
+ Position p(pos);
+ int ply = 0;
+
+ // Update position to the end of current PV
+ while (pv[ply] != MOVE_NONE)
+ p.do_move(pv[ply++], st);
+
+ // Try to add moves from TT while possible
+ while ( (tte = retrieve(p.get_key())) != NULL
+ && tte->move() != MOVE_NONE
+ && move_is_legal(p, tte->move())
+ && (!p.is_draw() || ply < 2)
+ && ply < PLY_MAX)
{
- if (!move_is_legal(p, tte->move()))
- break;
pv[ply] = tte->move();
- p.do_move(pv[ply], st[ply]);
- for (int j = 0; j < ply; j++)
- if (st[j].key == p.get_key()) stop = true;
+ p.do_move(pv[ply++], st);
}
pv[ply] = MOVE_NONE;
}