template<MoveType Type, SquareDelta Delta>
inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) {
- // Calculate our parametrized parameters at compile time
- const Bitboard TRank8BB = (Delta == DELTA_NE || Delta == DELTA_NW ? Rank8BB : Rank1BB);
const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
Bitboard b;
Square to;
// Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black)
- if (Type == CAPTURE || Type == EVASION)
- {
- b = move_pawns<Delta>(pawns) & target & ~TFileABB & ~TRank8BB;
- SERIALIZE_MOVES_D(b, -Delta);
- }
+ b = move_pawns<Delta>(pawns) & target & ~TFileABB;
+ SERIALIZE_MOVES_D(b, -Delta);
return mlist;
}
template<Color Us, MoveType Type, SquareDelta Delta>
- inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawns, Bitboard target) {
+ inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) {
- // Calculate our parametrized parameters at compile time
- const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
- const bool IsPush = (Delta == DELTA_N || Delta == DELTA_S);
Bitboard b;
Square to;
- // Promotions and under-promotions
- b = move_pawns<Delta>(pawns) & target & TRank8BB;
+ // Promotions and under-promotions, both captures and non-captures
+ b = move_pawns<Delta>(pawnsOn7) & target;
if (Delta != DELTA_N && Delta != DELTA_S)
b &= ~TFileABB;
(*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT);
}
- // This is the only possible under promotion that can give a check
- // not already included in the queen-promotion. It is not sure that
- // the promoted knight will give check, but it doesn't worth to verify.
- if (Type == CHECK && !IsPush)
- (*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT);
-
// This is the only possible under promotion that can give a check
// not already included in the queen-promotion.
- if (Type == CHECK && IsPush && bit_is_set(pos.attacks_from<KNIGHT>(to), pos.king_square(opposite_color(Us))))
+ if ( Type == CHECK
+ && bit_is_set(pos.attacks_from<KNIGHT>(to), pos.king_square(opposite_color(Us))))
(*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT);
+ else (void)pos; // Silence a warning under MSVC
}
return mlist;
}
template<Color Us, MoveType Type>
MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) {
- // Calculate our parametrized parameters at compile time
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
- const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
- const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ // Calculate our parametrized parameters at compile time, named
+ // according to the point of view of white side.
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
Square to;
- Bitboard b1, b2, enemyPieces, emptySquares;
+ Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares;
Bitboard pawns = pos.pieces(PAWN, Us);
+ Bitboard pawnsOn7 = pawns & TRank7BB;
+ Bitboard enemyPieces = (Type == CAPTURE ? target : pos.pieces_of_color(Them));
- // Standard captures and capturing promotions and underpromotions
- if (Type == CAPTURE || Type == EVASION || (pawns & TRank7BB))
+ // Pre-calculate pawn pushes before changing emptySquares definition
+ if (Type != CAPTURE)
{
- enemyPieces = (Type == CAPTURE ? target : pos.pieces_of_color(opposite_color(Us)));
-
- if (Type == EVASION)
- enemyPieces &= target; // Capture only the checker piece
+ emptySquares = (Type == NON_CAPTURE ? target : pos.empty_squares());
+ pawnPushes = move_pawns<TDELTA_N>(pawns & ~TRank7BB) & emptySquares;
+ }
- mlist = generate_promotions<Us, Type, TDELTA_NE>(pos, mlist, pawns, enemyPieces);
- mlist = generate_pawn_captures<Type, TDELTA_NE>(mlist, pawns, enemyPieces);
- mlist = generate_promotions<Us, Type, TDELTA_NW>(pos, mlist, pawns, enemyPieces);
- mlist = generate_pawn_captures<Type, TDELTA_NW>(mlist, pawns, enemyPieces);
+ if (Type == EVASION)
+ {
+ emptySquares &= target; // Only blocking squares
+ enemyPieces &= target; // Capture only the checker piece
}
- // Non-capturing promotions and underpromotions
- if (pawns & TRank7BB)
+ // Promotions and underpromotions
+ if (pawnsOn7)
{
- b1 = pos.empty_squares();
+ if (Type == CAPTURE)
+ emptySquares = pos.empty_squares();
- if (Type == EVASION)
- b1 &= target; // Only blocking promotion pushes
+ pawns &= ~TRank7BB;
+ mlist = generate_promotions<Us, Type, TDELTA_NE>(pos, mlist, pawnsOn7, enemyPieces);
+ mlist = generate_promotions<Us, Type, TDELTA_NW>(pos, mlist, pawnsOn7, enemyPieces);
+ mlist = generate_promotions<Us, Type, TDELTA_N >(pos, mlist, pawnsOn7, emptySquares);
+ }
- mlist = generate_promotions<Us, Type, TDELTA_N>(pos, mlist, pawns, b1);
+ // Standard captures
+ if (Type == CAPTURE || Type == EVASION)
+ {
+ mlist = generate_pawn_captures<Type, TDELTA_NE>(mlist, pawns, enemyPieces);
+ mlist = generate_pawn_captures<Type, TDELTA_NW>(mlist, pawns, enemyPieces);
}
- // Standard pawn pushes and double pushes
+ // Single and double pawn pushes
if (Type != CAPTURE)
{
- emptySquares = (Type == NON_CAPTURE ? target : pos.empty_squares());
-
- // Single and double pawn pushes
- b1 = move_pawns<TDELTA_N>(pawns) & emptySquares & ~TRank8BB;
- b2 = move_pawns<TDELTA_N>(b1 & TRank3BB) & emptySquares;
+ b1 = pawnPushes & emptySquares;
+ b2 = move_pawns<TDELTA_N>(pawnPushes & TRank3BB) & emptySquares;
- // Filter out unwanted pushes according to the move type
- if (Type == EVASION)
- {
- b1 &= target;
- b2 &= target;
- }
- else if (Type == CHECK)
+ if (Type == CHECK)
{
- // Pawn moves which give direct cheks
+ // Condider only pawn moves which give direct checks
b1 &= pos.attacks_from<PAWN>(ksq, Them);
b2 &= pos.attacks_from<PAWN>(ksq, Them);
- // Pawn moves which gives discovered check. This is possible only if
- // the pawn is not on the same file as the enemy king, because we
- // don't generate captures.
+ // Add pawn moves which gives discovered check. This is possible only
+ // if the pawn is not on the same file as the enemy king, because we
+ // don't generate captures.
if (pawns & target) // For CHECK type target is dc bitboard
{
- Bitboard dc1 = move_pawns<TDELTA_N>(pawns & target & ~file_bb(ksq)) & emptySquares & ~TRank8BB;
- Bitboard dc2 = move_pawns<TDELTA_N>(dc1 & TRank3BB) & emptySquares;
+ dc1 = move_pawns<TDELTA_N>(pawns & target & ~file_bb(ksq)) & emptySquares;
+ dc2 = move_pawns<TDELTA_N>(dc1 & TRank3BB) & emptySquares;
b1 |= dc1;
b2 |= dc2;