Align pinmask handling with checkmask (#295)

Bench: 6645600
PGG106 · Jan 3, 2024 · 9633c74 · 9633c74
1 parent 4a081e7
commit 9633c74
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Showing 7 changed files with 57 additions and 48 deletions.
diff --git a/src/board.cpp b/src/board.cpp
@@ -238,6 +238,8 @@ void ParseFen(const std::string& command, S_Board* pos) {
     else
         pos->checkMask = fullCheckmask;
 
+    UpdatePinMasks(pos, pos->side);
+
     // Update nnue accumulator to reflect board state
     Accumulate(pos->accumStack[0], pos);
     pos->accumStackHead = 1;
@@ -402,8 +404,8 @@ int KingSQ(const S_Board* pos, const int c) {
 }
 
 Bitboard GetCheckersBB(const S_Board* pos, const int side) {
+    const int kingSquare = KingSQ(pos, side);
     Bitboard Occ = pos->Occupancy(BOTH);
-    int kingSquare = KingSQ(pos, side);
     // Bitboard of pawns that attack the king square
     const Bitboard pawn_mask = pos->GetPieceColorBB(PAWN, side ^ 1) & pawn_attacks[side][kingSquare];
     // Bitboard of knights that attack the king square
@@ -439,6 +441,38 @@ Bitboard GetCheckersBB(const S_Board* pos, const int side) {
     return checkers;
 }
 
+void UpdatePinMasks(S_Board* pos, const int side) {
+    const int kingSquare = KingSQ(pos, side);
+    Bitboard them = pos->Enemy();
+    // Bitboard of bishops and queens that diagonally attack the king square
+    const Bitboard bishopsQueens = pos->GetPieceColorBB(BISHOP, side^1) | pos->GetPieceColorBB(QUEEN, side^1);
+    // Bitboard of rooks and queens that attack the king square
+    const Bitboard rooksQueens = pos->GetPieceColorBB(ROOK, side^1) | pos->GetPieceColorBB(QUEEN, side^1);
+    Bitboard bishop_pin_mask = bishopsQueens & GetBishopAttacks(kingSquare, them);
+    // Bitboard of rooks and queens that attack the king square
+    Bitboard rook_pin_mask = rooksQueens & GetRookAttacks(kingSquare, them);
+
+    Bitboard bishop_pin, rook_pin;
+    bishop_pin = rook_pin = 0ULL;
+
+    while (bishop_pin_mask) {
+        int index = GetLsbIndex(bishop_pin_mask);
+        Bitboard possible_pin = RayBetween(kingSquare, index) | (1ULL << index);
+        if (CountBits(possible_pin & pos->Occupancy(side)) == 1)
+            bishop_pin |= possible_pin;
+        pop_bit(bishop_pin_mask, index);
+    }
+    while (rook_pin_mask) {
+        int index = GetLsbIndex(rook_pin_mask);
+        Bitboard possible_pin = RayBetween(kingSquare, index) | (1ULL << index);
+        if (CountBits(possible_pin & pos->Occupancy(side)) == 1)
+            rook_pin |= possible_pin;
+        pop_bit(rook_pin_mask, index);
+    }
+    pos->pinHV = rook_pin;
+    pos->pinD = bishop_pin;
+}
+
 Bitboard RayBetween(int square1, int square2) {
     return SQUARES_BETWEEN_BB[square1][square2];
 }

diff --git a/src/board.h b/src/board.h
@@ -78,6 +78,8 @@ struct S_Undo {
     int plyFromNull = 0;
     Bitboard checkers = 0ULL;
     Bitboard checkMask = fullCheckmask;
+    Bitboard pinHV;
+    Bitboard pinD;
 }; // stores a move and the state of the game before that move is made
 // for rollback purposes
 
@@ -252,6 +254,7 @@ void ResetInfo(S_SearchINFO* info);
 // Get on what square of the board the king of color c resides
 [[nodiscard]] int KingSQ(const S_Board* pos, const int c);
 [[nodiscard]] Bitboard GetCheckersBB(const S_Board* pos, const int side);
+void UpdatePinMasks(S_Board* pos, const int side);
 Bitboard RayBetween(int square1, int square2);
 [[nodiscard]] int GetEpSquare(const S_Board* pos);
 [[nodiscard]] uint64_t GetMaterialValue(const S_Board* pos);

diff --git a/src/init.cpp b/src/init.cpp
@@ -163,37 +163,6 @@ void initializeLookupTables() {
     }
 }
 
-void DoPinMask(S_Board* pos, int color, int sq) {
-    Bitboard them = pos->Enemy();
-    Bitboard bishop_mask = (pos->bitboards[(color ^ 1) * 6 + 2] |
-        pos->bitboards[(color ^ 1) * 6 + 4]) &
-        GetBishopAttacks(sq, them);
-    Bitboard rook_mask = (pos->bitboards[(color ^ 1) * 6 + 3] |
-        pos->bitboards[0 + (color ^ 1) * 6 + 4]) &
-        GetRookAttacks(sq, them);
-    Bitboard rook_pin = 0ULL;
-    Bitboard bishop_pin = 0ULL;
-    pos->pinD = 0ULL;
-    pos->pinHV = 0ULL;
-
-    while (rook_mask) {
-        int index = GetLsbIndex(rook_mask);
-        Bitboard possible_pin = (SQUARES_BETWEEN_BB[sq][index] | (1ULL << index));
-        if (CountBits(possible_pin & pos->occupancies[color]) == 1)
-            rook_pin |= possible_pin;
-        pop_bit(rook_mask, index);
-    }
-    while (bishop_mask) {
-        int index = GetLsbIndex(bishop_mask);
-        Bitboard possible_pin = (SQUARES_BETWEEN_BB[sq][index] | (1ULL << index));
-        if (CountBits(possible_pin & pos->occupancies[color]) == 1)
-            bishop_pin |= possible_pin;
-        pop_bit(bishop_mask, index);
-    }
-    pos->pinHV = rook_pin;
-    pos->pinD = bishop_pin;
-}
-
 // PreCalculate the logarithms used in the reduction calculation
 void InitReductions() {
     // Avoid log(0) because it's bad

diff --git a/src/init.h b/src/init.h
@@ -18,7 +18,3 @@ void InitLeapersAttacks();
 void InitSlidersAttacks();
 
 void InitAll();
-
-[[nodiscard]] Bitboard DoCheckmask(S_Board* pos, int color, int sq);
-
-void DoPinMask(S_Board* pos, int color, int sq);
diff --git a/src/makemove.cpp b/src/makemove.cpp
@@ -171,6 +171,8 @@ void MakeUCIMove(const int move, S_Board* pos) {
     }
     else
         pos->checkMask = fullCheckmask;
+    // Update pinmasks
+    UpdatePinMasks(pos, pos->side);
 }
 
 // make move on chess board
@@ -182,7 +184,8 @@ void MakeMove(const int move, S_Board* pos) {
     pos->history[pos->hisPly].plyFromNull = pos->plyFromNull;
     pos->history[pos->hisPly].checkers = pos->checkers;
     pos->history[pos->hisPly].checkMask = pos->checkMask;
-
+    pos->history[pos->hisPly].pinHV = pos->pinHV;
+    pos->history[pos->hisPly].pinD = pos->pinD;
     // Store position key in the array of searched position
     pos->played_positions.emplace_back(pos->posKey);
 
@@ -217,6 +220,7 @@ void MakeMove(const int move, S_Board* pos) {
     else if (capture) {
         const int pieceCap = pos->pieces[targetSquare];
         assert(pieceCap != EMPTY);
+        assert(GetPieceType(pieceCap) != KING);
         ClearPieceNNUE(pieceCap, targetSquare, pos);
 
         pos->history[pos->hisPly].capture = pieceCap;
@@ -292,6 +296,8 @@ void MakeMove(const int move, S_Board* pos) {
     }
     else
         pos->checkMask = fullCheckmask;
+    // Update pinmasks
+    UpdatePinMasks(pos, pos->side);
 }
 
 void UnmakeMove(const int move, S_Board* pos) {
@@ -305,6 +311,8 @@ void UnmakeMove(const int move, S_Board* pos) {
     pos->plyFromNull = pos->history[pos->hisPly].plyFromNull;
     pos->checkers = pos->history[pos->hisPly].checkers;
     pos->checkMask = pos->history[pos->hisPly].checkMask;
+    pos->pinHV = pos->history[pos->hisPly].pinHV;
+    pos->pinD = pos->history[pos->hisPly].pinD;
 
     // parse move
     const int sourceSquare = From(move);
@@ -389,6 +397,8 @@ void MakeNullMove(S_Board* pos) {
     pos->history[pos->hisPly].plyFromNull = pos->plyFromNull;
     pos->history[pos->hisPly].checkers = pos->checkers;
     pos->history[pos->hisPly].checkMask = pos->checkMask;
+    pos->history[pos->hisPly].pinHV = pos->pinHV;
+    pos->history[pos->hisPly].pinD = pos->pinD;
     // Store position key in the array of searched position
     pos->played_positions.emplace_back(pos->posKey);
 
@@ -404,18 +414,22 @@ void MakeNullMove(S_Board* pos) {
 
     pos->ChangeSide();
     HashKey(pos, SideKey);
+    // Update pinmasks
+    UpdatePinMasks(pos, pos->side);
 }
 
 // Take back a null move
 void TakeNullMove(S_Board* pos) {
     pos->hisPly--;
 
-    pos->castleperm = pos->history[pos->hisPly].castlePerm;
-    pos->fiftyMove = pos->history[pos->hisPly].fiftyMove;
     pos->enPas = pos->history[pos->hisPly].enPas;
+    pos->fiftyMove = pos->history[pos->hisPly].fiftyMove;
+    pos->castleperm = pos->history[pos->hisPly].castlePerm;
     pos->plyFromNull = pos->history[pos->hisPly].plyFromNull;
     pos->checkers = pos->history[pos->hisPly].checkers;
     pos->checkMask = pos->history[pos->hisPly].checkMask;
+    pos->pinHV = pos->history[pos->hisPly].pinHV;
+    pos->pinD = pos->history[pos->hisPly].pinD;
 
     pos->ChangeSide();
     pos->posKey = pos->played_positions.back();

diff --git a/src/movegen.cpp b/src/movegen.cpp
@@ -35,9 +35,6 @@ static inline Bitboard PawnPush(int color, int sq) {
     return (1ULL << (sq + 8));
 }
 
-static inline void init(S_Board* pos, int color, int sq) {
-    DoPinMask(pos, color, sq);
-}
 // Check for move legality by generating the list of legal moves in a position and checking if that move is present
 int MoveExists(S_Board* pos, const int move) {
     S_MOVELIST list[1];
@@ -199,10 +196,8 @@ void GenerateMoves(S_MOVELIST* move_list, S_Board* pos) { // init move count
     // define source & target squares
     int sourceSquare, targetSquare;
 
-    init(pos, pos->side, KingSQ(pos, pos->side));
-
     const int checks = CountBits(pos->checkers);
-
+    
     if (checks < 2) {
         Bitboard pawns = pos->GetPieceColorBB(PAWN, pos->side);
         while (pawns) {
@@ -353,8 +348,6 @@ void GenerateCaptures(S_MOVELIST* move_list, S_Board* pos) {
     // define source & target squares
     int sourceSquare, targetSquare;
 
-    init(pos, pos->side, KingSQ(pos, pos->side));
-
     const int checks = CountBits(pos->checkers);
 
     if (checks < 2) {

diff --git a/src/types.h b/src/types.h
@@ -2,7 +2,7 @@
 
 #include <cstdint>
 
-#define NAME "Alexandria-5.1.11.1"
+#define NAME "Alexandria-5.1.12"
 
 // define bitboard data type
 using Bitboard = uint64_t;