/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
*/
#include <cassert>
+#include <algorithm>
#include "bitcount.h"
#include "movegen.h"
+#include "position.h"
+#include "misc.h"
// Simple macro to wrap a very common while loop, no facny, no flexibility,
// hardcoded list name 'mlist' and from square 'from'.
namespace {
- enum CastlingSide {
- KING_SIDE,
- QUEEN_SIDE
- };
+ enum CastlingSide { KING_SIDE, QUEEN_SIDE };
- template<CastlingSide>
- MoveStack* generate_castle_moves(const Position&, MoveStack*, Color us);
+ template<CastlingSide Side>
+ MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) {
- template<Color, MoveType>
- MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square);
+ const CastleRight CR[] = { Side ? WHITE_OOO : WHITE_OO,
+ Side ? BLACK_OOO : BLACK_OO };
- template<PieceType Pt>
- inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) {
+ if (!pos.can_castle(CR[us]))
+ return mlist;
+
+ // After castling, the rook and king final positions are the same in Chess960
+ // as they would be in standard chess.
+ Square kfrom = pos.king_square(us);
+ Square rfrom = pos.castle_rook_square(CR[us]);
+ Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
+ Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
+ Bitboard enemies = pos.pieces(flip(us));
+
+ assert(!pos.in_check());
+ assert(pos.piece_on(kfrom) == make_piece(us, KING));
+ assert(pos.piece_on(rfrom) == make_piece(us, ROOK));
+
+ // Unimpeded rule: All the squares between the king's initial and final squares
+ // (including the final square), and all the squares between the rook's initial
+ // and final squares (including the final square), must be vacant except for
+ // the king and castling rook.
+ for (Square s = std::min(rfrom, rto), e = std::max(rfrom, rto); s <= e; s++)
+ if (s != kfrom && s != rfrom && !pos.square_is_empty(s))
+ return mlist;
- assert(Pt != QUEEN);
+ for (Square s = std::min(kfrom, kto), e = std::max(kfrom, kto); s <= e; s++)
+ if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s))
+ ||(pos.attackers_to(s) & enemies))
+ return mlist;
- Bitboard b = pos.attacks_from<Pt>(from) & pos.empty_squares();
- if (Pt == KING)
+ // Because we generate only legal castling moves we need to verify that
+ // when moving the castling rook we do not discover some hidden checker.
+ // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1.
+ if (pos.is_chess960())
{
- Square ksq = pos.king_square(opposite_color(pos.side_to_move()));
- b &= ~QueenPseudoAttacks[ksq];
+ Bitboard occ = pos.occupied_squares();
+ clear_bit(&occ, rfrom);
+ if (pos.attackers_to(kto, occ) & enemies)
+ return mlist;
}
- SERIALIZE_MOVES(b);
+
+ (*mlist++).move = make_castle(kfrom, rfrom);
+
+ return mlist;
+ }
+
+
+ template<Square Delta>
+ inline Bitboard move_pawns(Bitboard p) {
+
+ return Delta == DELTA_N ? p << 8 : Delta == DELTA_S ? p >> 8 :
+ Delta == DELTA_NE ? p << 9 : Delta == DELTA_SE ? p >> 7 :
+ Delta == DELTA_NW ? p << 7 : Delta == DELTA_SW ? p >> 9 : p;
+ }
+
+
+ template<Square Delta>
+ inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) {
+
+ const Bitboard TFileABB = ( Delta == DELTA_NE
+ || Delta == DELTA_SE ? FileABB : FileHBB);
+ Bitboard b;
+ Square to;
+
+ b = move_pawns<Delta>(pawns) & target & ~TFileABB;
+ SERIALIZE_MOVES_D(b, -Delta);
return mlist;
}
+
+ template<MoveType Type, Square Delta>
+ inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) {
+
+ const Bitboard TFileABB = ( Delta == DELTA_NE
+ || Delta == DELTA_SE ? FileABB : FileHBB);
+ Bitboard b;
+ Square to;
+
+ b = move_pawns<Delta>(pawnsOn7) & target;
+
+ if (Delta != DELTA_N && Delta != DELTA_S)
+ b &= ~TFileABB;
+
+ while (b)
+ {
+ to = pop_1st_bit(&b);
+
+ if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
+ (*mlist++).move = make_promotion(to - Delta, to, QUEEN);
+
+ if (Type == MV_NON_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
+ {
+ (*mlist++).move = make_promotion(to - Delta, to, ROOK);
+ (*mlist++).move = make_promotion(to - Delta, to, BISHOP);
+ (*mlist++).move = make_promotion(to - Delta, to, KNIGHT);
+ }
+
+ // Knight-promotion is the only one that can give a check (direct or
+ // discovered) not already included in the queen-promotion.
+ if ( Type == MV_CHECK
+ && bit_is_set(StepAttacksBB[W_KNIGHT][to], ksq))
+ (*mlist++).move = make_promotion(to - Delta, to, KNIGHT);
+ else
+ (void)ksq; // 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, 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 Square UP = (Us == WHITE ? DELTA_N : DELTA_S);
+ const Square RIGHT = (Us == WHITE ? DELTA_NE : DELTA_SW);
+ const Square LEFT = (Us == WHITE ? DELTA_NW : DELTA_SE);
+
+ Square to;
+ Bitboard b1, b2, dc1, dc2, emptySquares;
+
+ Bitboard pawns = pos.pieces(PAWN, Us);
+ Bitboard pawnsOn7 = pawns & TRank7BB;
+ Bitboard pawnsNotOn7 = pawns & ~TRank7BB;
+
+ Bitboard enemies = (Type == MV_EVASION ? pos.pieces(Them) & target:
+ Type == MV_CAPTURE ? target : pos.pieces(Them));
+
+ // Single and double pawn pushes, no promotions
+ if (Type != MV_CAPTURE)
+ {
+ emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares());
+
+ b1 = move_pawns<UP>(pawnsNotOn7) & emptySquares;
+ b2 = move_pawns<UP>(b1 & TRank3BB) & emptySquares;
+
+ if (Type == MV_EVASION)
+ {
+ b1 &= target; // Consider only blocking squares
+ b2 &= target;
+ }
+
+ if (Type == MV_CHECK)
+ {
+ // Consider only direct checks
+ b1 &= pos.attacks_from<PAWN>(ksq, Them);
+ b2 &= pos.attacks_from<PAWN>(ksq, Them);
+
+ // Add pawn pushes which give 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. Note that a possible discovery check
+ // promotion has been already generated among captures.
+ if (pawnsNotOn7 & target) // For CHECK type target is dc bitboard
+ {
+ dc1 = move_pawns<UP>(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq);
+ dc2 = move_pawns<UP>(dc1 & TRank3BB) & emptySquares;
+
+ b1 |= dc1;
+ b2 |= dc2;
+ }
+ }
+
+ SERIALIZE_MOVES_D(b1, -UP);
+ SERIALIZE_MOVES_D(b2, -UP -UP);
+ }
+
+ // Promotions and underpromotions
+ if (pawnsOn7)
+ {
+ if (Type == MV_CAPTURE)
+ emptySquares = pos.empty_squares();
+
+ if (Type == MV_EVASION)
+ emptySquares &= target;
+
+ mlist = generate_promotions<Type, RIGHT>(mlist, pawnsOn7, enemies, ksq);
+ mlist = generate_promotions<Type, LEFT>(mlist, pawnsOn7, enemies, ksq);
+ mlist = generate_promotions<Type, UP>(mlist, pawnsOn7, emptySquares, ksq);
+ }
+
+ // Standard and en-passant captures
+ if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION)
+ {
+ mlist = generate_pawn_captures<RIGHT>(mlist, pawnsNotOn7, enemies);
+ mlist = generate_pawn_captures<LEFT >(mlist, pawnsNotOn7, enemies);
+
+ if (pos.ep_square() != SQ_NONE)
+ {
+ assert(rank_of(pos.ep_square()) == (Us == WHITE ? RANK_6 : RANK_3));
+
+ // An en passant capture can be an evasion only if the checking piece
+ // is the double pushed pawn and so is in the target. Otherwise this
+ // is a discovery check and we are forced to do otherwise.
+ if (Type == MV_EVASION && !bit_is_set(target, pos.ep_square() - UP))
+ return mlist;
+
+ b1 = pawnsNotOn7 & pos.attacks_from<PAWN>(pos.ep_square(), Them);
+
+ assert(b1);
+
+ while (b1)
+ (*mlist++).move = make_enpassant(pop_1st_bit(&b1), pos.ep_square());
+ }
+ }
+
+ return mlist;
+ }
+
+
template<PieceType Pt>
inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
Bitboard dc, Square ksq) {
- assert(Pt != KING);
+ assert(Pt != KING && Pt != PAWN);
Bitboard checkSqs, b;
Square from;
return mlist;
}
+
template<>
FORCE_INLINE MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
: generate_pawn_moves<BLACK, MV_CHECK>(p, m, dc, ksq));
}
+
template<PieceType Pt, MoveType Type>
FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) {
assert(Pt == PAWN);
- assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION);
-
return (us == WHITE ? generate_pawn_moves<WHITE, Type>(p, m, t, SQ_NONE)
: generate_pawn_moves<BLACK, Type>(p, m, t, SQ_NONE));
}
+
template<PieceType Pt>
FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
return mlist;
}
+
template<>
FORCE_INLINE MoveStack* generate_piece_moves<KING>(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
return mlist;
}
-}
+} // namespace
/// generate<MV_CAPTURE> generates all pseudo-legal captures and queen
template<MoveType Type>
MoveStack* generate(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
+ assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_NON_EVASION);
assert(!pos.in_check());
Color us = pos.side_to_move();
Bitboard target;
- if (Type == MV_CAPTURE || Type == MV_NON_EVASION)
- target = pos.pieces(opposite_color(us));
+ if (Type == MV_CAPTURE)
+ target = pos.pieces(flip(us));
+
else if (Type == MV_NON_CAPTURE)
target = pos.empty_squares();
- else
- assert(false);
- if (Type == MV_NON_EVASION)
- {
- mlist = generate_piece_moves<PAWN, MV_CAPTURE>(pos, mlist, us, target);
- mlist = generate_piece_moves<PAWN, MV_NON_CAPTURE>(pos, mlist, us, pos.empty_squares());
- target |= pos.empty_squares();
- }
- else
- mlist = generate_piece_moves<PAWN, Type>(pos, mlist, us, target);
+ else if (Type == MV_NON_EVASION)
+ target = pos.pieces(flip(us)) | pos.empty_squares();
+ mlist = generate_piece_moves<PAWN, Type>(pos, mlist, us, target);
mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
if (Type != MV_CAPTURE && pos.can_castle(us))
{
- if (pos.can_castle(us == WHITE ? WHITE_OO : BLACK_OO))
- mlist = generate_castle_moves<KING_SIDE>(pos, mlist, us);
-
- if (pos.can_castle(us == WHITE ? WHITE_OOO : BLACK_OOO))
- mlist = generate_castle_moves<QUEEN_SIDE>(pos, mlist, us);
+ mlist = generate_castle_moves<KING_SIDE>(pos, mlist, us);
+ mlist = generate_castle_moves<QUEEN_SIDE>(pos, mlist, us);
}
return mlist;
template MoveStack* generate<MV_NON_EVASION>(const Position& pos, MoveStack* mlist);
-/// generate_non_capture_checks() generates all pseudo-legal non-captures and knight
+/// generate<MV_NON_CAPTURE_CHECK> generates all pseudo-legal non-captures and knight
/// underpromotions that give check. Returns a pointer to the end of the move list.
template<>
MoveStack* generate<MV_NON_CAPTURE_CHECK>(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
assert(!pos.in_check());
Bitboard b, dc;
Square from;
+ PieceType pt;
Color us = pos.side_to_move();
- Square ksq = pos.king_square(opposite_color(us));
+ Square ksq = pos.king_square(flip(us));
- assert(pos.piece_on(ksq) == make_piece(opposite_color(us), KING));
+ assert(pos.piece_on(ksq) == make_piece(flip(us), KING));
// Discovered non-capture checks
- b = dc = pos.discovered_check_candidates(us);
+ b = dc = pos.discovered_check_candidates();
while (b)
{
from = pop_1st_bit(&b);
- switch (piece_type(pos.piece_on(from)))
- {
- case PAWN: /* Will be generated togheter with pawns direct checks */ break;
- case KNIGHT: mlist = generate_discovered_checks<KNIGHT>(pos, mlist, from); break;
- case BISHOP: mlist = generate_discovered_checks<BISHOP>(pos, mlist, from); break;
- case ROOK: mlist = generate_discovered_checks<ROOK>(pos, mlist, from); break;
- case KING: mlist = generate_discovered_checks<KING>(pos, mlist, from); break;
- default: assert(false); break;
- }
+ pt = type_of(pos.piece_on(from));
+
+ if (pt == PAWN)
+ continue; // Will be generated togheter with direct checks
+
+ b = pos.attacks_from(Piece(pt), from) & pos.empty_squares();
+
+ if (pt == KING)
+ b &= ~QueenPseudoAttacks[ksq];
+
+ SERIALIZE_MOVES(b);
}
// Direct non-capture checks
}
-/// generate_evasions() generates all pseudo-legal check evasions when
-/// the side to move is in check. Returns a pointer to the end of the move list.
+/// generate<MV_EVASION> generates all pseudo-legal check evasions when the side
+/// to move is in check. Returns a pointer to the end of the move list.
template<>
MoveStack* generate<MV_EVASION>(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
assert(pos.in_check());
Bitboard b, target;
Color us = pos.side_to_move();
Square ksq = pos.king_square(us);
Bitboard checkers = pos.checkers();
- Bitboard sliderAttacks = EmptyBoardBB;
+ Bitboard sliderAttacks = 0;
assert(pos.piece_on(ksq) == make_piece(us, KING));
assert(checkers);
checkersCnt++;
checksq = pop_1st_bit(&b);
- assert(piece_color(pos.piece_on(checksq)) == opposite_color(us));
+ assert(color_of(pos.piece_on(checksq)) == flip(us));
- switch (piece_type(pos.piece_on(checksq)))
+ switch (type_of(pos.piece_on(checksq)))
{
case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break;
case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break;
template<>
MoveStack* generate<MV_LEGAL>(const Position& pos, MoveStack* mlist) {
- assert(pos.is_ok());
-
MoveStack *last, *cur = mlist;
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+ Bitboard pinned = pos.pinned_pieces();
last = pos.in_check() ? generate<MV_EVASION>(pos, mlist)
: generate<MV_NON_EVASION>(pos, mlist);
return last;
}
-
-
-namespace {
-
- template<Square Delta>
- inline Bitboard move_pawns(Bitboard p) {
-
- return Delta == DELTA_N ? p << 8 : Delta == DELTA_S ? p >> 8 :
- Delta == DELTA_NE ? p << 9 : Delta == DELTA_SE ? p >> 7 :
- Delta == DELTA_NW ? p << 7 : Delta == DELTA_SW ? p >> 9 : p;
- }
-
- template<MoveType Type, Square Delta>
- inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) {
-
- 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)
- b = move_pawns<Delta>(pawns) & target & ~TFileABB;
- SERIALIZE_MOVES_D(b, -Delta);
- return mlist;
- }
-
- template<Color Us, MoveType Type, Square Delta>
- inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) {
-
- const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB);
-
- Bitboard b;
- Square to;
-
- // Promotions and under-promotions, both captures and non-captures
- b = move_pawns<Delta>(pawnsOn7) & target;
-
- if (Delta != DELTA_N && Delta != DELTA_S)
- b &= ~TFileABB;
-
- while (b)
- {
- to = pop_1st_bit(&b);
-
- if (Type == MV_CAPTURE || Type == MV_EVASION)
- (*mlist++).move = make_promotion_move(to - Delta, to, QUEEN);
-
- if (Type == MV_NON_CAPTURE || Type == MV_EVASION)
- {
- (*mlist++).move = make_promotion_move(to - Delta, to, ROOK);
- (*mlist++).move = make_promotion_move(to - Delta, to, BISHOP);
- (*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 == MV_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, 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 Square TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- const Square TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
- const Square TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
-
- Square to;
- Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares;
- Bitboard pawns = pos.pieces(PAWN, Us);
- Bitboard pawnsOn7 = pawns & TRank7BB;
- Bitboard enemyPieces = (Type == MV_CAPTURE ? target : pos.pieces(Them));
-
- // Pre-calculate pawn pushes before changing emptySquares definition
- if (Type != MV_CAPTURE)
- {
- emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares());
- pawnPushes = move_pawns<TDELTA_N>(pawns & ~TRank7BB) & emptySquares;
- }
-
- if (Type == MV_EVASION)
- {
- emptySquares &= target; // Only blocking squares
- enemyPieces &= target; // Capture only the checker piece
- }
-
- // Promotions and underpromotions
- if (pawnsOn7)
- {
- if (Type == MV_CAPTURE)
- emptySquares = pos.empty_squares();
-
- 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);
- }
-
- // Standard captures
- if (Type == MV_CAPTURE || Type == MV_EVASION)
- {
- mlist = generate_pawn_captures<Type, TDELTA_NE>(mlist, pawns, enemyPieces);
- mlist = generate_pawn_captures<Type, TDELTA_NW>(mlist, pawns, enemyPieces);
- }
-
- // Single and double pawn pushes
- if (Type != MV_CAPTURE)
- {
- b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares);
- b2 = move_pawns<TDELTA_N>(pawnPushes & TRank3BB) & emptySquares;
-
- if (Type == MV_CHECK)
- {
- // Consider only pawn moves which give direct checks
- b1 &= pos.attacks_from<PAWN>(ksq, Them);
- b2 &= pos.attacks_from<PAWN>(ksq, Them);
-
- // 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
- {
- dc1 = move_pawns<TDELTA_N>(pawns & target & ~file_bb(ksq)) & emptySquares;
- dc2 = move_pawns<TDELTA_N>(dc1 & TRank3BB) & emptySquares;
-
- b1 |= dc1;
- b2 |= dc2;
- }
- }
- SERIALIZE_MOVES_D(b1, -TDELTA_N);
- SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
- }
-
- // En passant captures
- if ((Type == MV_CAPTURE || Type == MV_EVASION) && pos.ep_square() != SQ_NONE)
- {
- assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6);
- assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3);
-
- // An en passant capture can be an evasion only if the checking piece
- // is the double pushed pawn and so is in the target. Otherwise this
- // is a discovery check and we are forced to do otherwise.
- if (Type == MV_EVASION && !bit_is_set(target, pos.ep_square() - TDELTA_N))
- return mlist;
-
- b1 = pawns & pos.attacks_from<PAWN>(pos.ep_square(), Them);
-
- assert(b1 != EmptyBoardBB);
-
- while (b1)
- {
- to = pop_1st_bit(&b1);
- (*mlist++).move = make_ep_move(to, pos.ep_square());
- }
- }
- return mlist;
- }
-
- template<CastlingSide Side>
- MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) {
-
- CastleRight f = CastleRight((Side == KING_SIDE ? WHITE_OO : WHITE_OOO) << us);
- Color them = opposite_color(us);
-
- // After castling, the rook and king's final positions are exactly the same
- // in Chess960 as they would be in standard chess.
- Square kfrom = pos.king_square(us);
- Square rfrom = pos.castle_rook_square(f);
- Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
- Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
-
- assert(!pos.in_check());
- assert(pos.piece_on(kfrom) == make_piece(us, KING));
- assert(pos.piece_on(rfrom) == make_piece(us, ROOK));
-
- // Unimpeded rule: All the squares between the king's initial and final squares
- // (including the final square), and all the squares between the rook's initial
- // and final squares (including the final square), must be vacant except for
- // the king and castling rook.
- for (Square s = Min(kfrom, kto); s <= Max(kfrom, kto); s++)
- if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- ||(pos.attackers_to(s) & pos.pieces(them)))
- return mlist;
-
- for (Square s = Min(rfrom, rto); s <= Max(rfrom, rto); s++)
- if (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- return mlist;
-
- // Because we generate only legal castling moves we need to verify that
- // when moving the castling rook we do not discover some hidden checker.
- // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1.
- if (pos.is_chess960())
- {
- Bitboard occ = pos.occupied_squares();
- clear_bit(&occ, rfrom);
- if (pos.attackers_to(kto, occ) & pos.pieces(them))
- return mlist;
- }
-
- (*mlist++).move = make_castle_move(kfrom, rfrom);
-
- return mlist;
- }
-
-} // namespace
projects / stockfish / blobdiff