constexpr int TBPIECES = 6; // Max number of supported pieces
-enum TBType { WDL, DTZ }; // Used as template parameter
+enum { BigEndian, LittleEndian };
+enum TBType { KEY, WDL, DTZ }; // Used as template parameter
// Each table has a set of flags: all of them refer to DTZ tables, the last one to WDL tables
enum TBFlag { STM = 1, Mapped = 2, WinPlies = 4, LossPlies = 8, SingleValue = 128 };
inline Square operator^=(Square& s, int i) { return s = Square(int(s) ^ i); }
inline Square operator^(Square s, int i) { return Square(int(s) ^ i); }
-// DTZ tables don't store valid scores for moves that reset the rule50 counter
-// like captures and pawn moves but we can easily recover the correct dtz of the
-// previous move if we know the position's WDL score.
-int dtz_before_zeroing(WDLScore wdl) {
- return wdl == WDLWin ? 1 :
- wdl == WDLCursedWin ? 101 :
- wdl == WDLBlessedLoss ? -101 :
- wdl == WDLLoss ? -1 : 0;
-}
-
-// Return the sign of a number (-1, 0, 1)
-template <typename T> int sign_of(T val) {
- return (T(0) < val) - (val < T(0));
-}
-
-// Numbers in little endian used by sparseIndex[] to point into blockLength[]
-struct SparseEntry {
- char block[4]; // Number of block
- char offset[2]; // Offset within the block
-};
-
-static_assert(sizeof(SparseEntry) == 6, "SparseEntry must be 6 bytes");
-
-typedef uint16_t Sym; // Huffman symbol
-
-struct LR {
- enum Side { Left, Right, Value };
-
- uint8_t lr[3]; // The first 12 bits is the left-hand symbol, the second 12
- // bits is the right-hand symbol. If symbol has length 1,
- // then the first byte is the stored value.
- template<Side S>
- Sym get() {
- return S == Left ? ((lr[1] & 0xF) << 8) | lr[0] :
- S == Right ? (lr[2] << 4) | (lr[1] >> 4) :
- S == Value ? lr[0] : (assert(false), Sym(-1));
- }
-};
-
-static_assert(sizeof(LR) == 3, "LR tree entry must be 3 bytes");
-
-struct PairsData {
- int flags;
- size_t sizeofBlock; // Block size in bytes
- size_t span; // About every span values there is a SparseIndex[] entry
- int blocksNum; // Number of blocks in the TB file
- int maxSymLen; // Maximum length in bits of the Huffman symbols
- int minSymLen; // Minimum length in bits of the Huffman symbols
- Sym* lowestSym; // lowestSym[l] is the symbol of length l with the lowest value
- LR* btree; // btree[sym] stores the left and right symbols that expand sym
- uint16_t* blockLength; // Number of stored positions (minus one) for each block: 1..65536
- int blockLengthSize; // Size of blockLength[] table: padded so it's bigger than blocksNum
- SparseEntry* sparseIndex; // Partial indices into blockLength[]
- size_t sparseIndexSize; // Size of SparseIndex[] table
- uint8_t* data; // Start of Huffman compressed data
- std::vector<uint64_t> base64; // base64[l - min_sym_len] is the 64bit-padded lowest symbol of length l
- std::vector<uint8_t> symlen; // Number of values (-1) represented by a given Huffman symbol: 1..256
- Piece pieces[TBPIECES]; // Position pieces: the order of pieces defines the groups
- uint64_t groupIdx[TBPIECES+1]; // Start index used for the encoding of the group's pieces
- int groupLen[TBPIECES+1]; // Number of pieces in a given group: KRKN -> (3, 1)
- uint16_t map_idx[4]; // WDLWin, WDLLoss, WDLCursedWin, WDLBlessedLoss (used in DTZ)
-};
-
-template<TBType Type>
-struct TBEntry {
- typedef typename std::conditional<Type == WDL, WDLScore, int>::type Result;
-
- static constexpr int Sides = Type == WDL ? 2 : 1;
-
- std::atomic_bool ready;
- void* baseAddress;
- uint8_t* map;
- uint64_t mapping;
- Key key;
- Key key2;
- int pieceCount;
- bool hasPawns;
- bool hasUniquePieces;
- uint8_t pawnCount[2]; // [Lead color / other color]
- PairsData items[Sides][4]; // [wtm / btm][FILE_A..FILE_D or 0]
-
- PairsData* get(int stm, int f) {
- return &items[stm % Sides][hasPawns ? f : 0];
- }
-
- TBEntry() : ready(false), baseAddress(nullptr) {}
- explicit TBEntry(const std::string& code);
- explicit TBEntry(const TBEntry<WDL>& wdl);
- ~TBEntry();
-};
-
-template<>
-TBEntry<WDL>::TBEntry(const std::string& code) : TBEntry() {
-
- StateInfo st;
- Position pos;
-
- key = pos.set(code, WHITE, &st).material_key();
- pieceCount = popcount(pos.pieces());
- hasPawns = pos.pieces(PAWN);
-
- hasUniquePieces = false;
- for (Color c = WHITE; c <= BLACK; ++c)
- for (PieceType pt = PAWN; pt < KING; ++pt)
- if (popcount(pos.pieces(c, pt)) == 1)
- hasUniquePieces = true;
-
- if (hasPawns) {
- // Set the leading color. In case both sides have pawns the leading color
- // is the side with less pawns because this leads to better compression.
- bool c = !pos.count<PAWN>(BLACK)
- || ( pos.count<PAWN>(WHITE)
- && pos.count<PAWN>(BLACK) >= pos.count<PAWN>(WHITE));
-
- pawnCount[0] = pos.count<PAWN>(c ? WHITE : BLACK);
- pawnCount[1] = pos.count<PAWN>(c ? BLACK : WHITE);
- }
-
- key2 = pos.set(code, BLACK, &st).material_key();
-}
-
-template<>
-TBEntry<DTZ>::TBEntry(const TBEntry<WDL>& wdl) : TBEntry() {
-
- key = wdl.key;
- key2 = wdl.key2;
- pieceCount = wdl.pieceCount;
- hasPawns = wdl.hasPawns;
- hasUniquePieces = wdl.hasUniquePieces;
-
- if (hasPawns) {
- pawnCount[0] = wdl.pawnCount[0];
- pawnCount[1] = wdl.pawnCount[1];
- }
-}
+const std::string PieceToChar = " PNBRQK pnbrqk";
int MapPawns[SQUARE_NB];
int MapB1H1H7[SQUARE_NB];
int MapA1D1D4[SQUARE_NB];
int MapKK[10][SQUARE_NB]; // [MapA1D1D4][SQUARE_NB]
+int Binomial[6][SQUARE_NB]; // [k][n] k elements from a set of n elements
+int LeadPawnIdx[5][SQUARE_NB]; // [leadPawnsCnt][SQUARE_NB]
+int LeadPawnsSize[5][4]; // [leadPawnsCnt][FILE_A..FILE_D]
+
// Comparison function to sort leading pawns in ascending MapPawns[] order
bool pawns_comp(Square i, Square j) { return MapPawns[i] < MapPawns[j]; }
int off_A1H8(Square sq) { return int(rank_of(sq)) - file_of(sq); }
VALUE_MATE - MAX_PLY - 1
};
-const std::string PieceToChar = " PNBRQK pnbrqk";
-
-int Binomial[6][SQUARE_NB]; // [k][n] k elements from a set of n elements
-int LeadPawnIdx[5][SQUARE_NB]; // [leadPawnsCnt][SQUARE_NB]
-int LeadPawnsSize[5][4]; // [leadPawnsCnt][FILE_A..FILE_D]
-
-enum { BigEndian, LittleEndian };
-
template<typename T, int Half = sizeof(T) / 2, int End = sizeof(T) - 1>
-inline void swap_byte(T& x)
+inline void swap_endian(T& x)
{
- char tmp, *c = (char*)&x;
+ static_assert(std::is_unsigned<T>::value, "Argument of swap_endian not unsigned");
+
+ uint8_t tmp, *c = (uint8_t*)&x;
for (int i = 0; i < Half; ++i)
tmp = c[i], c[i] = c[End - i], c[End - i] = tmp;
}
-template<> inline void swap_byte<uint8_t, 0, 0>(uint8_t&) {}
+template<> inline void swap_endian<uint8_t>(uint8_t&) {}
template<typename T, int LE> T number(void* addr)
{
- const union { uint32_t i; char c[4]; } Le = { 0x01020304 };
- const bool IsLittleEndian = (Le.c[0] == 4);
+ static const union { uint32_t i; char c[4]; } Le = { 0x01020304 };
+ static const bool IsLittleEndian = (Le.c[0] == 4);
T v;
v = *((T*)addr);
if (LE != IsLittleEndian)
- swap_byte(v);
+ swap_endian(v);
return v;
}
-class HashTable {
-
- typedef std::pair<TBEntry<WDL>*, TBEntry<DTZ>*> EntryPair;
- typedef std::pair<Key, EntryPair> Entry;
-
- static constexpr int TBHASHBITS = 10;
- static constexpr int HSHMAX = 5;
-
- Entry hashTable[1 << TBHASHBITS][HSHMAX];
+// DTZ tables don't store valid scores for moves that reset the rule50 counter
+// like captures and pawn moves but we can easily recover the correct dtz of the
+// previous move if we know the position's WDL score.
+int dtz_before_zeroing(WDLScore wdl) {
+ return wdl == WDLWin ? 1 :
+ wdl == WDLCursedWin ? 101 :
+ wdl == WDLBlessedLoss ? -101 :
+ wdl == WDLLoss ? -1 : 0;
+}
- std::deque<TBEntry<WDL>> wdlTable;
- std::deque<TBEntry<DTZ>> dtzTable;
+// Return the sign of a number (-1, 0, 1)
+template <typename T> int sign_of(T val) {
+ return (T(0) < val) - (val < T(0));
+}
- void insert(Key key, TBEntry<WDL>* wdl, TBEntry<DTZ>* dtz) {
- for (Entry& entry : hashTable[key >> (64 - TBHASHBITS)])
- if (!entry.second.first || entry.first == key) {
- entry = std::make_pair(key, std::make_pair(wdl, dtz));
- return;
- }
+// Numbers in little endian used by sparseIndex[] to point into blockLength[]
+struct SparseEntry {
+ char block[4]; // Number of block
+ char offset[2]; // Offset within the block
+};
- std::cerr << "HSHMAX too low!" << std::endl;
- exit(1);
- }
+static_assert(sizeof(SparseEntry) == 6, "SparseEntry must be 6 bytes");
-public:
- template<TBType Type>
- TBEntry<Type>* get(Key key) {
- for (Entry& entry : hashTable[key >> (64 - TBHASHBITS)])
- if (entry.first == key)
- return std::get<Type>(entry.second);
+typedef uint16_t Sym; // Huffman symbol
- return nullptr;
- }
+struct LR {
+ enum Side { Left, Right, Value };
- void clear() {
- memset(hashTable, 0, sizeof(hashTable));
- wdlTable.clear();
- dtzTable.clear();
+ uint8_t lr[3]; // The first 12 bits is the left-hand symbol, the second 12
+ // bits is the right-hand symbol. If symbol has length 1,
+ // then the first byte is the stored value.
+ template<Side S>
+ Sym get() {
+ return S == Left ? ((lr[1] & 0xF) << 8) | lr[0] :
+ S == Right ? (lr[2] << 4) | (lr[1] >> 4) :
+ S == Value ? lr[0] : (assert(false), Sym(-1));
}
- size_t size() const { return wdlTable.size(); }
- void insert(const std::vector<PieceType>& pieces);
};
-HashTable EntryTable;
+static_assert(sizeof(LR) == 3, "LR tree entry must be 3 bytes");
+
+// Tablebases data layout is structured as following:
+//
+// TBFile: memory maps/unmaps the physical .rtbw and .rtbz files
+// TBTable: one object for each file with corresponding indexing information
+// TBTables: has ownership of TBTable objects, keeping a list and a hash
+// class TBFile memory maps/unmaps the single .rtbw and .rtbz files. Files are
+// memory mapped for best performance. Files are mapped at first access: at init
+// time only existence of the file is checked.
class TBFile : public std::ifstream {
std::string fname;
// Memory map the file and check it. File should be already open and will be
// closed after mapping.
- uint8_t* map(void** baseAddress, uint64_t* mapping, const uint8_t* TB_MAGIC) {
+ uint8_t* map(void** baseAddress, uint64_t* mapping, TBType type) {
assert(is_open());
#endif
uint8_t* data = (uint8_t*)*baseAddress;
- if ( *data++ != *TB_MAGIC++
- || *data++ != *TB_MAGIC++
- || *data++ != *TB_MAGIC++
- || *data++ != *TB_MAGIC) {
+ constexpr uint8_t Magics[][4] = { { 0xD7, 0x66, 0x0C, 0xA5 },
+ { 0x71, 0xE8, 0x23, 0x5D } };
+
+ if (memcmp(data, Magics[type == WDL], 4)) {
std::cerr << "Corrupted table in file " << fname << std::endl;
unmap(*baseAddress, *mapping);
return *baseAddress = nullptr, nullptr;
}
- return data;
+ return data + 4; // Skip Magics's header
}
static void unmap(void* baseAddress, uint64_t mapping) {
std::string TBFile::Paths;
+// struct PairsData contains low level indexing information to access TB data.
+// There are 8, 4 or 2 PairsData records for each TBTable, according to type of
+// table and if positions have pawns or not. It is populated at first access.
+struct PairsData {
+ uint8_t flags; // Table flags, see enum TBFlag
+ uint8_t maxSymLen; // Maximum length in bits of the Huffman symbols
+ uint8_t minSymLen; // Minimum length in bits of the Huffman symbols
+ uint32_t blocksNum; // Number of blocks in the TB file
+ size_t sizeofBlock; // Block size in bytes
+ size_t span; // About every span values there is a SparseIndex[] entry
+ Sym* lowestSym; // lowestSym[l] is the symbol of length l with the lowest value
+ LR* btree; // btree[sym] stores the left and right symbols that expand sym
+ uint16_t* blockLength; // Number of stored positions (minus one) for each block: 1..65536
+ uint32_t blockLengthSize; // Size of blockLength[] table: padded so it's bigger than blocksNum
+ SparseEntry* sparseIndex; // Partial indices into blockLength[]
+ size_t sparseIndexSize; // Size of SparseIndex[] table
+ uint8_t* data; // Start of Huffman compressed data
+ std::vector<uint64_t> base64; // base64[l - min_sym_len] is the 64bit-padded lowest symbol of length l
+ std::vector<uint8_t> symlen; // Number of values (-1) represented by a given Huffman symbol: 1..256
+ Piece pieces[TBPIECES]; // Position pieces: the order of pieces defines the groups
+ uint64_t groupIdx[TBPIECES+1]; // Start index used for the encoding of the group's pieces
+ int groupLen[TBPIECES+1]; // Number of pieces in a given group: KRKN -> (3, 1)
+ uint16_t map_idx[4]; // WDLWin, WDLLoss, WDLCursedWin, WDLBlessedLoss (used in DTZ)
+};
+
+// struct TBTable contains indexing information to access the corresponding TBFile.
+// There are 2 types of TBTable, corresponding to a WDL or a DTZ file. TBTable
+// is populated at init time but the nested PairsData records are populated at
+// first access, when the corresponding file is memory mapped.
template<TBType Type>
-TBEntry<Type>::~TBEntry() {
- if (baseAddress)
- TBFile::unmap(baseAddress, mapping);
+struct TBTable {
+ typedef typename std::conditional<Type == WDL, WDLScore, int>::type Ret;
+
+ static constexpr int Sides = Type == WDL ? 2 : 1;
+
+ std::atomic_bool ready;
+ void* baseAddress;
+ uint8_t* map;
+ uint64_t mapping;
+ Key key;
+ Key key2;
+ int pieceCount;
+ bool hasPawns;
+ bool hasUniquePieces;
+ uint8_t pawnCount[2]; // [Lead color / other color]
+ PairsData items[Sides][4]; // [wtm / btm][FILE_A..FILE_D or 0]
+
+ PairsData* get(int stm, int f) {
+ return &items[stm % Sides][hasPawns ? f : 0];
+ }
+
+ TBTable() : ready(false), baseAddress(nullptr) {}
+ explicit TBTable(const std::string& code);
+ explicit TBTable(const TBTable<WDL>& wdl);
+
+ ~TBTable() {
+ if (baseAddress)
+ TBFile::unmap(baseAddress, mapping);
+ }
+};
+
+template<>
+TBTable<WDL>::TBTable(const std::string& code) : TBTable() {
+
+ StateInfo st;
+ Position pos;
+
+ key = pos.set(code, WHITE, &st).material_key();
+ pieceCount = pos.count<ALL_PIECES>();
+ hasPawns = pos.pieces(PAWN);
+
+ hasUniquePieces = false;
+ for (Color c = WHITE; c <= BLACK; ++c)
+ for (PieceType pt = PAWN; pt < KING; ++pt)
+ if (popcount(pos.pieces(c, pt)) == 1)
+ hasUniquePieces = true;
+
+ // Set the leading color. In case both sides have pawns the leading color
+ // is the side with less pawns because this leads to better compression.
+ bool c = !pos.count<PAWN>(BLACK)
+ || ( pos.count<PAWN>(WHITE)
+ && pos.count<PAWN>(BLACK) >= pos.count<PAWN>(WHITE));
+
+ pawnCount[0] = pos.count<PAWN>(c ? WHITE : BLACK);
+ pawnCount[1] = pos.count<PAWN>(c ? BLACK : WHITE);
+
+ key2 = pos.set(code, BLACK, &st).material_key();
}
-void HashTable::insert(const std::vector<PieceType>& pieces) {
+template<>
+TBTable<DTZ>::TBTable(const TBTable<WDL>& wdl) : TBTable() {
+
+ // Use the corresponding WDL table to avoid recalculating all from scratch
+ key = wdl.key;
+ key2 = wdl.key2;
+ pieceCount = wdl.pieceCount;
+ hasPawns = wdl.hasPawns;
+ hasUniquePieces = wdl.hasUniquePieces;
+ pawnCount[0] = wdl.pawnCount[0];
+ pawnCount[1] = wdl.pawnCount[1];
+}
+
+// class TBTables creates and keeps ownership of the TBTable objects, one for
+// each TB file found. It supports a fast, hash based, table lookup. Populated
+// at init time, accessed at probe time.
+class TBTables {
+
+ typedef std::tuple<Key, TBTable<WDL>*, TBTable<DTZ>*> Entry;
+
+ static const int Size = 1 << 12; // 4K table, indexed by key's 12 lsb
+
+ Entry hashTable[Size];
+
+ std::deque<TBTable<WDL>> wdlTable;
+ std::deque<TBTable<DTZ>> dtzTable;
+
+ void insert(Key key, TBTable<WDL>* wdl, TBTable<DTZ>* dtz) {
+ Entry* entry = &hashTable[(uint32_t)key & (Size - 1)];
+
+ // Ensure last element is empty to avoid overflow when looking up
+ for ( ; entry - hashTable < Size - 1; ++entry)
+ if (std::get<KEY>(*entry) == key || !std::get<WDL>(*entry)) {
+ *entry = std::make_tuple(key, wdl, dtz);
+ return;
+ }
+ std::cerr << "TB hash table size too low!" << std::endl;
+ exit(1);
+ }
+
+public:
+ template<TBType Type>
+ TBTable<Type>* get(Key key) {
+ for (const Entry* entry = &hashTable[(uint32_t)key & (Size - 1)]; ; ++entry) {
+ if (std::get<KEY>(*entry) == key || !std::get<Type>(*entry))
+ return std::get<Type>(*entry);
+ }
+ }
+
+ void clear() {
+ memset(hashTable, 0, sizeof(hashTable));
+ wdlTable.clear();
+ dtzTable.clear();
+ }
+ size_t size() const { return wdlTable.size(); }
+ void add(const std::vector<PieceType>& pieces);
+};
+
+TBTables TBTables;
+
+// If the corresponding file exists two new objects TBTable<WDL> and TBTable<DTZ>
+// are created and added to the lists and hash table. Called at init time.
+void TBTables::add(const std::vector<PieceType>& pieces) {
std::string code;
wdlTable.emplace_back(code);
dtzTable.emplace_back(wdlTable.back());
+ // Insert into the hash keys for both colors: KRvK with KR white and black
insert(wdlTable.back().key , &wdlTable.back(), &dtzTable.back());
insert(wdlTable.back().key2, &wdlTable.back(), &dtzTable.back());
}
return d->btree[sym].get<LR::Value>();
}
-bool check_dtz_stm(TBEntry<WDL>*, int, File) { return true; }
+bool check_dtz_stm(TBTable<WDL>*, int, File) { return true; }
-bool check_dtz_stm(TBEntry<DTZ>* entry, int stm, File f) {
+bool check_dtz_stm(TBTable<DTZ>* entry, int stm, File f) {
- int flags = entry->get(stm, f)->flags;
+ auto flags = entry->get(stm, f)->flags;
return (flags & TBFlag::STM) == stm
|| ((entry->key == entry->key2) && !entry->hasPawns);
}
// values 0, 1, 2, ... in order of decreasing frequency. This is done for each
// of the four WDLScore values. The mapping information necessary to reconstruct
// the original values is stored in the TB file and read during map[] init.
-WDLScore map_score(TBEntry<WDL>*, File, int value, WDLScore) { return WDLScore(value - 2); }
+WDLScore map_score(TBTable<WDL>*, File, int value, WDLScore) { return WDLScore(value - 2); }
-int map_score(TBEntry<DTZ>* entry, File f, int value, WDLScore wdl) {
+int map_score(TBTable<DTZ>* entry, File f, int value, WDLScore wdl) {
constexpr int WDLMap[] = { 1, 3, 0, 2, 0 };
- int flags = entry->get(0, f)->flags;
+ auto flags = entry->get(0, f)->flags;
uint8_t* map = entry->map;
uint16_t* idx = entry->get(0, f)->map_idx;
//
// idx = Binomial[1][s1] + Binomial[2][s2] + ... + Binomial[k][sk]
//
-template<TBType Type, typename T = typename TBEntry<Type>::Result>
-T do_probe_table(const Position& pos, TBEntry<Type>* entry, WDLScore wdl, ProbeState* result) {
+template<typename T, typename Ret = typename T::Ret>
+Ret do_probe_table(const Position& pos, T* entry, WDLScore wdl, ProbeState* result) {
Square squares[TBPIECES];
Piece pieces[TBPIECES];
// DTZ tables are one-sided, i.e. they store positions only for white to
// move or only for black to move, so check for side to move to be stm,
// early exit otherwise.
- if (Type == DTZ && !check_dtz_stm(entry, stm, tbFile))
- return *result = CHANGE_STM, T();
+ if (!check_dtz_stm(entry, stm, tbFile))
+ return *result = CHANGE_STM, Ret();
// Now we are ready to get all the position pieces (but the lead pawns) and
// directly map them to the correct color and square.
//
// The actual grouping depends on the TB generator and can be inferred from the
// sequence of pieces in piece[] array.
-template<TBType Type>
-void set_groups(TBEntry<Type>& e, PairsData* d, int order[], File f) {
+template<typename T>
+void set_groups(T& e, PairsData* d, int order[], File f) {
int n = 0, firstLen = e.hasPawns ? 0 : e.hasUniquePieces ? 3 : 2;
d->groupLen[n] = 1;
d->sizeofBlock = 1ULL << *data++;
d->span = 1ULL << *data++;
d->sparseIndexSize = (tbSize + d->span - 1) / d->span; // Round up
- int padding = number<uint8_t, LittleEndian>(data++);
+ auto padding = number<uint8_t, LittleEndian>(data++);
d->blocksNum = number<uint32_t, LittleEndian>(data); data += sizeof(uint32_t);
d->blockLengthSize = d->blocksNum + padding; // Padded to ensure SparseIndex[]
// does not point out of range.
return data + d->symlen.size() * sizeof(LR) + (d->symlen.size() & 1);
}
-uint8_t* set_dtz_map(TBEntry<WDL>&, uint8_t*, File) { return nullptr; }
+uint8_t* set_dtz_map(TBTable<WDL>&, uint8_t* data, File) { return data; }
-uint8_t* set_dtz_map(TBEntry<DTZ>& e, uint8_t* data, File maxFile) {
+uint8_t* set_dtz_map(TBTable<DTZ>& e, uint8_t* data, File maxFile) {
e.map = data;
return data += (uintptr_t)data & 1; // Word alignment
}
-template<TBType Type>
-void do_init(TBEntry<Type>& e, uint8_t* data) {
+// Populate entry's PairsData records with data from the just memory mapped file.
+// Called at first access.
+template<typename T>
+void set(T& e, uint8_t* data) {
PairsData* d;
data++; // First byte stores flags
- const int sides = Type == WDL && (e.key != e.key2) ? 2 : 1;
+ const int sides = T::Sides == 2 && (e.key != e.key2) ? 2 : 1;
const File maxFile = e.hasPawns ? FILE_D : FILE_A;
bool pp = e.hasPawns && e.pawnCount[1]; // Pawns on both sides
for (int i = 0; i < sides; i++)
data = set_sizes(e.get(i, f), data);
- if (Type == DTZ)
- data = set_dtz_map(e, data, maxFile);
+ data = set_dtz_map(e, data, maxFile);
for (File f = FILE_A; f <= maxFile; ++f)
for (int i = 0; i < sides; i++) {
}
}
+// If the TB file corresponding to the given position is already memory mapped
+// then return its base address, otherwise try to memory map and init it. Called
+// at every probe, memory map and init only at first access. Function is thread
+// safe and can be called concurrently.
template<TBType Type>
-void* init(TBEntry<Type>& e, const Position& pos) {
+void* mapped(TBTable<Type>& e, const Position& pos) {
static Mutex mutex;
- // Avoid a thread reads 'ready' == true while another is still in do_init(),
- // this could happen due to compiler reordering.
+ // Use 'aquire' to avoid a thread reads 'ready' == true while another is
+ // still working, this could happen due to compiler reordering.
if (e.ready.load(std::memory_order_acquire))
- return e.baseAddress;
+ return e.baseAddress; // Could be nullptr if file does not exsist
std::unique_lock<Mutex> lk(mutex);
b += std::string(popcount(pos.pieces(BLACK, pt)), PieceToChar[pt]);
}
- constexpr uint8_t TB_MAGIC[][4] = { { 0xD7, 0x66, 0x0C, 0xA5 },
- { 0x71, 0xE8, 0x23, 0x5D } };
-
fname = (e.key == pos.material_key() ? w + 'v' + b : b + 'v' + w)
+ (Type == WDL ? ".rtbw" : ".rtbz");
- uint8_t* data = TBFile(fname).map(&e.baseAddress, &e.mapping,
- TB_MAGIC[Type == WDL]);
+ uint8_t* data = TBFile(fname).map(&e.baseAddress, &e.mapping, Type);
+
if (data)
- do_init(e, data);
+ set(e, data);
e.ready.store(true, std::memory_order_release);
return e.baseAddress;
}
-template<TBType Type, typename T = typename TBEntry<Type>::Result>
-T probe_table(const Position& pos, ProbeState* result, WDLScore wdl = WDLDraw) {
+template<TBType Type, typename Ret = typename TBTable<Type>::Ret>
+Ret probe_table(const Position& pos, ProbeState* result, WDLScore wdl = WDLDraw) {
- if (!(pos.pieces() ^ pos.pieces(KING)))
- return T(WDLDraw); // KvK
+ if (pos.count<ALL_PIECES>() == 2) // KvK
+ return Ret(WDLDraw);
- TBEntry<Type>* entry = EntryTable.get<Type>(pos.material_key());
+ TBTable<Type>* entry = TBTables.get<Type>(pos.material_key());
- if (!entry || !init(*entry, pos))
- return *result = FAIL, T();
+ if (!entry || !mapped(*entry, pos))
+ return *result = FAIL, Ret();
return do_probe_table(pos, entry, wdl, result);
}
} // namespace
+
+/// Tablebases::init() is called at startup and after every change to
+/// "SyzygyPath" UCI option to (re)create the various tables. It is not thread
+/// safe, nor it needs to be.
void Tablebases::init(const std::string& paths) {
- EntryTable.clear();
+ TBTables.clear();
MaxCardinality = 0;
TBFile::Paths = paths;
LeadPawnsSize[leadPawnsCnt][f] = idx;
}
+ // Add entries in TB tables if the corresponding ".rtbw" file exsists
for (PieceType p1 = PAWN; p1 < KING; ++p1) {
- EntryTable.insert({KING, p1, KING});
+ TBTables.add({KING, p1, KING});
for (PieceType p2 = PAWN; p2 <= p1; ++p2) {
- EntryTable.insert({KING, p1, p2, KING});
- EntryTable.insert({KING, p1, KING, p2});
+ TBTables.add({KING, p1, p2, KING});
+ TBTables.add({KING, p1, KING, p2});
for (PieceType p3 = PAWN; p3 < KING; ++p3)
- EntryTable.insert({KING, p1, p2, KING, p3});
+ TBTables.add({KING, p1, p2, KING, p3});
for (PieceType p3 = PAWN; p3 <= p2; ++p3) {
- EntryTable.insert({KING, p1, p2, p3, KING});
+ TBTables.add({KING, p1, p2, p3, KING});
for (PieceType p4 = PAWN; p4 <= p3; ++p4)
- EntryTable.insert({KING, p1, p2, p3, p4, KING});
+ TBTables.add({KING, p1, p2, p3, p4, KING});
for (PieceType p4 = PAWN; p4 < KING; ++p4)
- EntryTable.insert({KING, p1, p2, p3, KING, p4});
+ TBTables.add({KING, p1, p2, p3, KING, p4});
}
for (PieceType p3 = PAWN; p3 <= p1; ++p3)
for (PieceType p4 = PAWN; p4 <= (p1 == p3 ? p2 : p3); ++p4)
- EntryTable.insert({KING, p1, p2, KING, p3, p4});
+ TBTables.add({KING, p1, p2, KING, p3, p4});
}
}
- sync_cout << "info string Found " << EntryTable.size() << " tablebases" << sync_endl;
+ sync_cout << "info string Found " << TBTables.size() << " tablebases" << sync_endl;
}
// Probe the WDL table for a particular position.
// The return value is from the point of view of the side to move:
// n < -100 : loss, but draw under 50-move rule
// -100 <= n < -1 : loss in n ply (assuming 50-move counter == 0)
+// -1 : loss, the side to move is mated
// 0 : draw
// 1 < n <= 100 : win in n ply (assuming 50-move counter == 0)
// 100 < n : win, but draw under 50-move rule
dtz = zeroing ? -dtz_before_zeroing(search(pos, result))
: -probe_dtz(pos, result);
- pos.undo_move(move);
-
- if (*result == FAIL)
- return 0;
+ // If the move mates, force minDTZ to 1
+ if (dtz == 1 && pos.checkers() && MoveList<LEGAL>(pos).size() == 0)
+ minDTZ = 1;
// Convert result from 1-ply search. Zeroing moves are already accounted
// by dtz_before_zeroing() that returns the DTZ of the previous move.
// Skip the draws and if we are winning only pick positive dtz
if (dtz < minDTZ && sign_of(dtz) == sign_of(wdl))
minDTZ = dtz;
+
+ pos.undo_move(move);
+
+ if (*result == FAIL)
+ return 0;
}
- // Special handle a mate position, when there are no legal moves, in this
- // case return value is somewhat arbitrary, so stick to the original TB code
- // that returns -1 in this case.
+ // When there are no legal moves, the position is mate: we return -1
return minDTZ == 0xFFFF ? -1 : minDTZ;
}