X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Ftt.cpp;h=5ea6a808acf86b2ad256f8715bf5c59772e015b1;hb=166c09a7a0eafb706a961d6533c73cc248f6df94;hp=f2313eabf1c72eee350de8cdda7038519944d222;hpb=cd4604b05c2d61928b26ab50c5864c36ef1d3785;p=stockfish diff --git a/src/tt.cpp b/src/tt.cpp index f2313eab..5ea6a808 100644 --- a/src/tt.cpp +++ b/src/tt.cpp @@ -25,15 +25,16 @@ #include #include #include -#include #include "movegen.h" #include "tt.h" +#if defined(_MSC_VER) +#include +#endif -/// This is the number of TTEntry slots for each position -static const int ClusterSize = 5; - +// The main transposition table +TranspositionTable TT; //// //// Functions @@ -63,14 +64,14 @@ void TranspositionTable::set_size(unsigned mbSize) { // 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 @@ -89,7 +90,17 @@ void TranspositionTable::set_size(unsigned mbSize) { void TranspositionTable::clear() { - memset(entries, 0, size * ClusterSize * sizeof(TTEntry)); + memset(entries, 0, size * sizeof(TTCluster)); +} + + +/// TranspositionTable::first_entry returns a pointer to the first +/// entry of a cluster given a position. The low 32 bits of the key +/// are used to get the index in the table. + +inline TTEntry* TranspositionTable::first_entry(const Key posKey) const { + + return entries[uint32_t(posKey) & (size - 1)].data; } @@ -145,7 +156,7 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, TTEntry* TranspositionTable::retrieve(const Key posKey) const { uint32_t posKey32 = posKey >> 32; - TTEntry *tte = first_entry(posKey); + TTEntry* tte = first_entry(posKey); for (int i = 0; i < ClusterSize; i++, tte++) if (tte->key() == posKey32) @@ -154,26 +165,28 @@ TTEntry* TranspositionTable::retrieve(const Key posKey) const { return NULL; } + /// TranspositionTable::prefetch looks up the current position in the /// transposition table and load it in L1/L2 cache. This is a non /// 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(_MSC_VER) + char* addr = (char*)first_entry(posKey); + _mm_prefetch(addr, _MM_HINT_T0); + _mm_prefetch(addr+64, _MM_HINT_T0); +#else + // We need to force an asm volatile here because gcc builtin + // is optimized away by Intel compiler. + char* addr = (char*)first_entry(posKey); + asm volatile("prefetcht0 %0" :: "m" (addr)); +#endif } -/// TranspositionTable::first_entry returns a pointer to the first -/// entry of a cluster given a position. The low 32 bits of the key -/// are used to get the index in the table. - -inline TTEntry* TranspositionTable::first_entry(const Key posKey) const { - - return entries + ((uint32_t(posKey) & (size - 1)) * ClusterSize); -} /// TranspositionTable::new_search() is called at the beginning of every new /// search. It increments the "generation" variable, which is used to