internal static void init()
{
for (int i = 0; i < Constants.BROKER_SLOTS; i++)
{
_pool[i] = new CheckInfo[0];
}
}
internal static CheckInfo GetObject()
{
int slotID = System.Threading.Thread.CurrentThread.ManagedThreadId & Constants.BROKER_SLOT_MASK;
if (_cnt[slotID] == _pool[slotID].Length)
{
int poolLength = _pool[slotID].Length;
CheckInfo[] temp = new CheckInfo[poolLength + Constants.BrokerCapacity];
Array.Copy(_pool[slotID], temp, poolLength);
for (int i = 0; i < Constants.BrokerCapacity; i++)
{
temp[poolLength + i] = new CheckInfo();
}
_pool[slotID] = temp;
}
return _pool[slotID][_cnt[slotID]++];
}
private static void generate_all(
GenType type,
Position pos,
MoveStack[] mlist,
ref int mpos,
int us,
ulong target,
CheckInfo ci)
{
var Checks = type == GenType.QUIET_CHECKS;
generate_pawn_moves(us, type, pos, mlist, ref mpos, target, ci);
generate_moves(PieceTypeC.KNIGHT, Checks, pos, mlist, ref mpos, us, target, ci);
generate_moves(PieceTypeC.BISHOP, Checks, pos, mlist, ref mpos, us, target, ci);
generate_moves(PieceTypeC.ROOK, Checks, pos, mlist, ref mpos, us, target, ci);
generate_moves(PieceTypeC.QUEEN, Checks, pos, mlist, ref mpos, us, target, ci);
if (!Checks && type != GenType.EVASIONS)
{
Square from = pos.king_square(us);
Bitboard b = Position.attacks_from_KING(from) & target;
// SERIALIZE(b);
while (b != 0)
{
#if X64
Bitboard bb = b;
b &= (b - 1);
mlist[mpos++].move = ((Utils.BSFTable[((bb & (0xffffffffffffffff - bb + 1)) * DeBruijn_64) >> 58]) | (from << 6));
#else
mlist[mpos++].move = Utils.make_move(from, Utils.pop_lsb(ref b));
#endif
}
}
if (type != GenType.CAPTURES && type != GenType.EVASIONS && pos.can_castle_C(us) != 0)
{
generate_castle(CastlingSideC.KING_SIDE, Checks, pos, mlist, ref mpos, us);
generate_castle(CastlingSideC.QUEEN_SIDE, Checks, pos, mlist, ref mpos, us);
}
}
private static void generate_moves(
int Pt,
bool Checks,
Position pos,
MoveStack[] mlist,
ref int mpos,
int us,
ulong target,
CheckInfo ci)
{
Debug.Assert(Pt != PieceTypeC.KING && Pt != PieceTypeC.PAWN);
var pl = pos.pieceList[us][Pt];
var plPos = 0;
for (var from = pl[plPos]; from != SquareC.SQ_NONE; from = pl[++plPos])
{
if (Checks)
{
if ((Pt == PieceTypeC.BISHOP || Pt == PieceTypeC.ROOK || Pt == PieceTypeC.QUEEN)
&& ((Utils.PseudoAttacks[Pt][from] & (ulong)target & ci.checkSq[Pt]) == 0))
{
continue;
}
if ((ci.dcCandidates != 0) && (Utils.bit_is_set(ci.dcCandidates, from) != 0))
{
continue;
}
}
var b = pos.attacks_from_PTS(Pt, from) & (ulong)target;
if (Checks)
{
b &= ci.checkSq[Pt];
}
// SERIALIZE(b);
while (b != 0)
{
mlist[mpos++].move = Utils.make_move(from, Utils.pop_lsb(ref b));
}
}
}
private static void generate_promotions(
GenType Type,
int Delta,
MoveStack[] ms,
ref int mpos,
ulong pawnsOn7,
ulong target,
CheckInfo ci)
{
var b = move_pawns(Delta, pawnsOn7) & target;
while (b != 0)
{
var to = Utils.pop_lsb(ref b);
if (Type == GenType.CAPTURES || Type == GenType.EVASIONS || Type == GenType.NON_EVASIONS)
{
ms[mpos++].move = Utils.make(to - Delta, to, MoveTypeC.PROMOTION, PieceTypeC.QUEEN);
}
if (Type == GenType.QUIETS || Type == GenType.EVASIONS || Type == GenType.NON_EVASIONS)
{
ms[mpos++].move = Utils.make(to - Delta, to, MoveTypeC.PROMOTION, PieceTypeC.ROOK);
ms[mpos++].move = Utils.make(to - Delta, to, MoveTypeC.PROMOTION, PieceTypeC.BISHOP);
ms[mpos++].move = Utils.make(to - Delta, to, MoveTypeC.PROMOTION, PieceTypeC.KNIGHT);
}
// Knight-promotion is the only one that can give a direct check not
// already included in the queen-promotion.
if (Type == GenType.QUIET_CHECKS
&& (Utils.bit_is_set(Utils.StepAttacksBB[PieceC.W_KNIGHT][to], ci.ksq) != 0))
{
ms[mpos++].move = Utils.make(to - Delta, to, MoveTypeC.PROMOTION, PieceTypeC.KNIGHT);
}
}
}
private static void generate_pawn_moves(
int Us,
GenType Type,
Position pos,
MoveStack[] ms,
ref int mpos,
ulong target,
CheckInfo ci)
{
// Compute our parametrized parameters at compile time, named according to
// the point of view of white side.
var Them = (Us == ColorC.WHITE ? ColorC.BLACK : ColorC.WHITE);
var TRank8BB = (Us == ColorC.WHITE ? Constants.Rank8BB : Constants.Rank1BB);
var TRank7BB = (Us == ColorC.WHITE ? Constants.Rank7BB : Constants.Rank2BB);
var TRank3BB = (Us == ColorC.WHITE ? Constants.Rank3BB : Constants.Rank6BB);
var UP = (Us == ColorC.WHITE ? SquareC.DELTA_N : SquareC.DELTA_S);
var RIGHT = (Us == ColorC.WHITE ? SquareC.DELTA_NE : SquareC.DELTA_SW);
var LEFT = (Us == ColorC.WHITE ? SquareC.DELTA_NW : SquareC.DELTA_SE);
ulong b1, b2, dc1, dc2, emptySquares = 0;
int to;
var pawnsOn7 = (pos.byTypeBB[PieceTypeC.PAWN] & pos.byColorBB[Us]) & TRank7BB;
var pawnsNotOn7 = (pos.byTypeBB[PieceTypeC.PAWN] & pos.byColorBB[Us]) & ~TRank7BB;
var enemies = (Type == GenType.EVASIONS
? pos.byColorBB[Them] & target
: Type == GenType.CAPTURES ? target : pos.byColorBB[Them]);
// Single and double pawn pushes, no promotions
if (Type != GenType.CAPTURES)
{
emptySquares = (Type == GenType.QUIETS ? target : ~pos.occupied_squares);
b1 = move_pawns(UP, pawnsNotOn7) & emptySquares;
b2 = move_pawns(UP, b1 & TRank3BB) & emptySquares;
if (Type == GenType.EVASIONS) // Consider only blocking squares
{
b1 &= target;
b2 &= target;
}
if (Type == GenType.QUIET_CHECKS)
{
b1 &= Utils.StepAttacksBB[((Them << 3) | PieceTypeC.PAWN)][ci.ksq];
b2 &= Utils.StepAttacksBB[((Them << 3) | PieceTypeC.PAWN)][ci.ksq];
// 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 & ci.dcCandidates) != 0) // Target is dc bitboard
{
dc1 = move_pawns(UP, pawnsNotOn7 & ci.dcCandidates) & emptySquares & ~(Utils.FileBB[ci.ksq & 7]);
dc2 = move_pawns(UP, dc1 & TRank3BB) & emptySquares;
b1 |= dc1;
b2 |= dc2;
}
}
while (b1 != 0)
{
to = Utils.pop_lsb(ref b1);
ms[mpos++].move = (to | ((to - UP) << 6));
}
while (b2 != 0)
{
to = Utils.pop_lsb(ref b2);
ms[mpos++].move = (to | ((to - UP - UP) << 6));
}
}
// Promotions and underpromotions
if ((pawnsOn7 != 0) && (Type != GenType.EVASIONS || ((target & TRank8BB) != 0)))
{
if (Type == GenType.CAPTURES)
{
emptySquares = ~pos.occupied_squares;
}
if (Type == GenType.EVASIONS)
{
emptySquares &= target;
}
generate_promotions(Type, RIGHT, ms, ref mpos, pawnsOn7, enemies, ci);
generate_promotions(Type, LEFT, ms, ref mpos, pawnsOn7, enemies, ci);
generate_promotions(Type, UP, ms, ref mpos, pawnsOn7, emptySquares, ci);
}
// Standard and en-passant captures
if (Type == GenType.CAPTURES || Type == GenType.EVASIONS || Type == GenType.NON_EVASIONS)
{
b1 = move_pawns(RIGHT, pawnsNotOn7) & enemies;
b2 = move_pawns(LEFT, pawnsNotOn7) & enemies;
while (b1 != 0)
{
to = Utils.pop_lsb(ref b1);
ms[mpos++].move = (to | ((to - RIGHT) << 6));
}
while (b2 != 0)
{
to = Utils.pop_lsb(ref b2);
ms[mpos++].move = (to | ((to - LEFT) << 6));
}
if (pos.st.epSquare != SquareC.SQ_NONE)
{
Debug.Assert(Utils.rank_of(pos.st.epSquare) == Utils.relative_rank_CR(Us, RankC.RANK_6));
// 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 == GenType.EVASIONS && (((target & Utils.SquareBB[pos.st.epSquare - UP]) == 0)))
{
return;
}
b1 = pawnsNotOn7 & Utils.StepAttacksBB[((Them << 3) | PieceTypeC.PAWN)][pos.st.epSquare];
Debug.Assert(b1 != 0);
while (b1 != 0)
{
ms[mpos++].move = Utils.make(Utils.pop_lsb(ref b1), pos.st.epSquare, MoveTypeC.ENPASSANT);
}
}
}
}
private static void generate_direct_checks(PieceType Pt, Position pos, MoveStack[] ms, ref int mpos, Color us, CheckInfo ci)
{
Debug.Assert(Pt != PieceTypeC.KING && Pt != PieceTypeC.PAWN);
Bitboard b, target;
Square[] pl = pos.pieceList[us][Pt];
int plPos = 0;
Square from = pl[plPos];
if ((from = pl[plPos]) != SquareC.SQ_NONE)
{
target = ci.checkSq[Pt] & ~pos.occupied_squares; // Non capture checks only
do
{
if ((Pt == PieceTypeC.BISHOP || Pt == PieceTypeC.ROOK || Pt == PieceTypeC.QUEEN)
&& ((Utils.PseudoAttacks[Pt][from] & target) == 0))
continue;
if ((ci.dcCandidates != 0) && (Utils.bit_is_set(ci.dcCandidates, from) != 0))
continue;
b = pos.attacks_from_PTS(Pt, from) & target;
while (b != 0) { ms[mpos++].move = Utils.make_move(from, Utils.pop_1st_bit(ref b)); }
} while ((from = pl[++plPos]) != SquareC.SQ_NONE);
}
}
internal void do_move(Move m, StateInfo newSt, CheckInfo ci, bool moveIsCheck)
{
Debug.Assert(Utils.is_ok_M(m));
Debug.Assert(newSt != st);
nodes++;
Key k = st.key;
newSt.pawnKey = st.pawnKey;
newSt.materialKey = st.materialKey;
newSt.npMaterialWHITE = st.npMaterialWHITE;
newSt.npMaterialBLACK = st.npMaterialBLACK;
newSt.castleRights = st.castleRights;
newSt.rule50 = st.rule50;
newSt.pliesFromNull = st.pliesFromNull;
newSt.psqScore = st.psqScore;
newSt.epSquare = st.epSquare;
newSt.previous = st;
st = newSt;
// Update side to move
k ^= zobSideToMove;
// Increment the 50 moves rule draw counter. Resetting it to zero in the
// case of a capture or a pawn move is taken care of later.
st.rule50++;
st.pliesFromNull++;
if ((m & (3 << 14)) == (3 << 14))
{
st.key = k;
do_castle_move(true, m);
return;
}
Color us = sideToMove;
Color them = us ^ 1;
Square from = ((m >> 6) & 0x3F);
Square to = (m & 0x3F);
Piece piece = board[from];
PieceType pt = (piece & 7);
PieceType capture = ((m & (3 << 14)) == (2 << 14)) ? PieceTypeC.PAWN : (board[to] & 7);
Debug.Assert(Utils.color_of(piece) == us);
Debug.Assert(Utils.color_of(piece_on(to)) != us);
Debug.Assert(capture != PieceTypeC.KING);
if (capture != 0)
{
Square capsq = to;
// If the captured piece is a pawn, update pawn hash key, otherwise
// update non-pawn material.
if (capture == PieceTypeC.PAWN)
{
if ((m & (3 << 14)) == (2 << 14))
{
capsq += (them == ColorC.WHITE ? SquareC.DELTA_N : SquareC.DELTA_S);
Debug.Assert(pt == PieceTypeC.PAWN);
Debug.Assert(to == st.epSquare);
Debug.Assert(Utils.relative_rank_CS(us, to) == RankC.RANK_6);
Debug.Assert(piece_on(to) == PieceC.NO_PIECE);
Debug.Assert(piece_on(capsq) == Utils.make_piece(them, PieceTypeC.PAWN));
board[capsq] = PieceC.NO_PIECE;
}
st.pawnKey ^= zobrist[them][PieceTypeC.PAWN][capsq];
}
else
{
if (them == 0) { st.npMaterialWHITE -= PieceValueMidgame[capture]; } else { st.npMaterialBLACK -= PieceValueMidgame[capture]; }
}
// Remove the captured piece
Bitboard capPieceMask = Utils.SquareBB[capsq];
occupied_squares ^= capPieceMask;
byTypeBB[capture] ^= capPieceMask;
byColorBB[them] ^= capPieceMask;
// Update piece list, move the last piece at index[capsq] position and
// shrink the list.
//
// WARNING: This is a not revresible operation. When we will reinsert the
// captured piece in undo_move() we will put it at the end of the list and
// not in its original place, it means index[] and pieceList[] are not
// guaranteed to be invariant to a do_move() + undo_move() sequence.
int[] plThemCapture = pieceList[them][capture];
int pcThemCapture = --pieceCount[them][capture];
Square lastSquare = plThemCapture[pcThemCapture];
index[lastSquare] = index[capsq];
plThemCapture[index[lastSquare]] = lastSquare;
plThemCapture[pcThemCapture] = SquareC.SQ_NONE;
// Update hash keys
k ^= zobrist[them][capture][capsq];
st.materialKey ^= zobrist[them][capture][pcThemCapture];
// Update incremental scores
st.psqScore -= pieceSquareTable[((them << 3) | capture)][capsq];
// Reset rule 50 counter
st.rule50 = 0;
}
// Update hash key
k ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
// Reset en passant square
if (st.epSquare != SquareC.SQ_NONE)
{
k ^= zobEp[st.epSquare & 7];
st.epSquare = SquareC.SQ_NONE;
}
// Update castle rights if needed
if ((st.castleRights != 0) && ((castleRightsMask[from] | castleRightsMask[to]) != 0))
{
int cr = castleRightsMask[from] | castleRightsMask[to];
k ^= zobCastle[st.castleRights & cr];
st.castleRights &= ~cr;
}
// Move the piece
Bitboard from_to_bb = Utils.SquareBB[from] ^ Utils.SquareBB[to];
occupied_squares ^= from_to_bb;
byTypeBB[pt] ^= from_to_bb;
byColorBB[us] ^= from_to_bb;
board[to] = board[from];
board[from] = PieceC.NO_PIECE;
// Update piece lists, index[from] is not updated and becomes stale. This
// works as long as index[] is accessed just by known occupied squares.
index[to] = index[from];
pieceList[us][pt][index[to]] = to;
// If the moving piece is a pawn do some special extra work
if (pt == PieceTypeC.PAWN)
{
// Set en-passant square, only if moved pawn can be captured
if ((to ^ from) == 16
&& ((((Utils.StepAttacksBB[((us << 3) | PieceTypeC.PAWN)][from + (us == ColorC.WHITE ? SquareC.DELTA_N : SquareC.DELTA_S)]) & (byTypeBB[PieceTypeC.PAWN] & byColorBB[them]))) != 0))
{
st.epSquare = ((from + to) / 2);
k ^= zobEp[st.epSquare & 7];
}
if ((m & (3 << 14)) == (1 << 14))
{
PieceType promotion = (((m >> 12) & 3) + 2);
Debug.Assert(Utils.relative_rank_CS(us, to) == RankC.RANK_8);
Debug.Assert(promotion >= PieceTypeC.KNIGHT && promotion <= PieceTypeC.QUEEN);
// Replace the pawn with the promoted piece
byTypeBB[PieceTypeC.PAWN] ^= Utils.SquareBB[to];
byTypeBB[promotion] |= Utils.SquareBB[to];
board[to] = ((us << 3) | promotion);
// Update piece lists, move the last pawn at index[to] position
// and shrink the list. Add a new promotion piece to the list.
int[] plUsPawn = pieceList[us][PieceTypeC.PAWN];
Square lastSquare = plUsPawn[--pieceCount[us][PieceTypeC.PAWN]];
index[lastSquare] = index[to];
plUsPawn[index[lastSquare]] = lastSquare;
plUsPawn[pieceCount[us][PieceTypeC.PAWN]] = SquareC.SQ_NONE;
index[to] = pieceCount[us][promotion];
pieceList[us][promotion][index[to]] = to;
// Update hash keys
k ^= zobrist[us][PieceTypeC.PAWN][to] ^ zobrist[us][promotion][to];
st.pawnKey ^= zobrist[us][PieceTypeC.PAWN][to];
st.materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]++]
^ zobrist[us][PieceTypeC.PAWN][pieceCount[us][PieceTypeC.PAWN]];
// Update incremental score
st.psqScore += pieceSquareTable[((us << 3) | promotion)][to] - pieceSquareTable[((us << 3) | PieceTypeC.PAWN)][to];
// Update material
if (us == 0) { st.npMaterialWHITE += PieceValueMidgame[promotion]; }
else { st.npMaterialBLACK += PieceValueMidgame[promotion]; }
}
// Update pawn hash key
st.pawnKey ^= zobrist[us][PieceTypeC.PAWN][from] ^ zobrist[us][PieceTypeC.PAWN][to];
// Reset rule 50 draw counter
st.rule50 = 0;
}
// Update incremental scores
st.psqScore += (pieceSquareTable[piece][to] - pieceSquareTable[piece][from]);
// Set capture piece
st.capturedType = capture;
// Update the key with the final value
st.key = k;
// Update checkers bitboard, piece must be already moved
st.checkersBB = 0;
if (moveIsCheck)
{
if ((m & (3 << 14)) != 0)
st.checkersBB = attackers_to(pieceList[them][PieceTypeC.KING][0]) & byColorBB[us];
else
{
// Direct checks
if ((ci.checkSq[pt] & Utils.SquareBB[to]) != 0)
{
st.checkersBB |= Utils.SquareBB[to];
}
// Discovery checks
if ((ci.dcCandidates != 0) && ((ci.dcCandidates & Utils.SquareBB[from]) != 0))
{
if (pt != PieceTypeC.ROOK)
st.checkersBB |= attacks_from_ROOK(pieceList[them][PieceTypeC.KING][0]) & ((byTypeBB[PieceTypeC.ROOK] | byTypeBB[PieceTypeC.QUEEN]) & byColorBB[us]);
if (pt != PieceTypeC.BISHOP)
st.checkersBB |= attacks_from_BISHOP(pieceList[them][PieceTypeC.KING][0]) & ((byTypeBB[PieceTypeC.BISHOP] | byTypeBB[PieceTypeC.QUEEN]) & byColorBB[us]);
}
}
}
// Finish
sideToMove = sideToMove ^ 1;
Debug.Assert(pos_is_ok());
}
/// move_gives_check() tests whether a pseudo-legal move gives a check
internal bool move_gives_check(Move m, CheckInfo ci)
{
Debug.Assert(Utils.is_ok_M(m));
Debug.Assert(ci.dcCandidates == discovered_check_candidates());
Debug.Assert(Utils.color_of(piece_moved(m)) == sideToMove);
Square from = (m >> 6) & 0x3F;
Square to = m & 0x3F;
PieceType pt = board[from] & 7;
// Direct check ?
if ((ci.checkSq[pt] & Utils.SquareBB[to]) != 0)
return true;
// Discovery check ?
if ((ci.dcCandidates != 0) && ((ci.dcCandidates & Utils.SquareBB[from]) != 0))
{
// For pawn and king moves we need to verify also direction
if ((pt != PieceTypeC.PAWN && pt != PieceTypeC.KING)
|| (((Utils.BetweenBB[from][to] | Utils.BetweenBB[from][pieceList[sideToMove ^ 1][PieceTypeC.KING][0]] | Utils.BetweenBB[to][pieceList[sideToMove ^ 1][PieceTypeC.KING][0]]) & (Utils.SquareBB[from] | Utils.SquareBB[to] | Utils.SquareBB[pieceList[sideToMove ^ 1][PieceTypeC.KING][0]])) == 0))
return true;
}
// Can we skip the ugly special cases ?
if ((m & (3 << 14)) == 0)
return false;
Color us = sideToMove;
Square ksq = pieceList[sideToMove ^ 1][PieceTypeC.KING][0];
// Promotion with check ?
if ((m & (3 << 14)) == (1 << 14))
{
return (attacks_from((((m >> 12) & 3) + 2), to, occupied_squares ^ Utils.SquareBB[from]) & Utils.SquareBB[ksq]) != 0;
}
// En passant capture with check ? We have already handled the case
// of direct checks and ordinary discovered check, the only case we
// need to handle is the unusual case of a discovered check through
// the captured pawn.
if ((m & (3 << 14)) == (2 << 14))
{
Square capsq = (((from >> 3) << 3) | (to & 7));
Bitboard b = (occupied_squares ^ Utils.SquareBB[from] ^ Utils.SquareBB[capsq]) | Utils.SquareBB[to];
return ((Utils.rook_attacks_bb(ksq, b) & ((byTypeBB[PieceTypeC.ROOK] | byTypeBB[PieceTypeC.QUEEN]) & byColorBB[us])) != 0)
|| ((Utils.bishop_attacks_bb(ksq, b) & ((byTypeBB[PieceTypeC.BISHOP] | byTypeBB[PieceTypeC.QUEEN]) & byColorBB[us])) != 0);
}
// Castling with check ?
if ((m & (3 << 14)) == (3 << 14))
{
Square kfrom = from;
Square rfrom = to; // 'King captures the rook' notation
Square kto = ((rfrom > kfrom ? SquareC.SQ_G1 : SquareC.SQ_C1) ^ (us * 56));
Square rto = ((rfrom > kfrom ? SquareC.SQ_F1 : SquareC.SQ_D1) ^ (us * 56));
Bitboard b = (occupied_squares ^ Utils.SquareBB[kfrom] ^ Utils.SquareBB[rfrom]) | Utils.SquareBB[rto] | Utils.SquareBB[kto];
return (Utils.rook_attacks_bb(rto, b) & Utils.SquareBB[ksq]) != 0;
}
return false;
}
internal void do_move(int m, StateInfo newSt, CheckInfo ci, bool moveIsCheck)
{
Debug.Assert(Utils.is_ok_M(m));
Debug.Assert(newSt != this.st);
this.nodes++;
var k = this.st.key;
newSt.pawnKey = this.st.pawnKey;
newSt.materialKey = this.st.materialKey;
newSt.npMaterialWHITE = this.st.npMaterialWHITE;
newSt.npMaterialBLACK = this.st.npMaterialBLACK;
newSt.castleRights = this.st.castleRights;
newSt.rule50 = this.st.rule50;
newSt.pliesFromNull = this.st.pliesFromNull;
newSt.psqScore = this.st.psqScore;
newSt.epSquare = this.st.epSquare;
newSt.previous = this.st;
this.st = newSt;
// Update side to move
k ^= Zobrist.side;
// Increment the 50 moves rule draw counter. Resetting it to zero in the
// case of a capture or a pawn move is taken care of later.
this.st.rule50++;
this.st.pliesFromNull++;
var us = this.sideToMove;
var them = us ^ 1;
Square from = Utils.from_sq(m);
Square to = Utils.to_sq(m);
Piece piece = piece_on(from);
PieceType pt = Utils.type_of(piece);
PieceType capture = Utils.type_of_move(m) == MoveTypeC.ENPASSANT ? PieceTypeC.PAWN : Utils.type_of(piece_on(to));
Debug.Assert(Utils.color_of(piece) == us);
Debug.Assert(piece_on(to) == PieceC.NO_PIECE || Utils.color_of(piece_on(to)) == them || Utils.type_of_move(m) == MoveTypeC.CASTLING);
Debug.Assert(capture != PieceTypeC.KING);
if (Utils.type_of_move(m) == MoveTypeC.CASTLING)
{
Debug.Assert(piece == Utils.make_piece(us, PieceTypeC.KING));
bool kingSide = to > from;
Square rfrom = to; // Castle is encoded as "king captures friendly rook"
Square rto = Utils.relative_square(us, kingSide ? SquareC.SQ_F1 : SquareC.SQ_D1);
to = Utils.relative_square(us, kingSide ? SquareC.SQ_G1 : SquareC.SQ_C1);
capture = PieceTypeC.NO_PIECE_TYPE;
do_castle(from, to, rfrom, rto);
st.psqScore += psq_delta(Utils.make_piece(us, PieceTypeC.ROOK), rfrom, rto);
k ^= Zobrist.psq[us][PieceTypeC.ROOK][rfrom] ^ Zobrist.psq[us][PieceTypeC.ROOK][rto];
}
if (capture != 0)
{
var capsq = to;
// If the captured piece is a pawn, update pawn hash key, otherwise
// update non-pawn material.
if (capture == PieceTypeC.PAWN)
{
if (Utils.type_of_move(m) == MoveTypeC.ENPASSANT)
{
capsq += (them == ColorC.WHITE ? SquareC.DELTA_N : SquareC.DELTA_S);
Debug.Assert(pt == PieceTypeC.PAWN);
Debug.Assert(to == this.st.epSquare);
Debug.Assert(Utils.relative_rank_CS(us, to) == RankC.RANK_6);
Debug.Assert(this.piece_on(to) == PieceC.NO_PIECE);
Debug.Assert(this.piece_on(capsq) == Utils.make_piece(them, PieceTypeC.PAWN));
this.board[capsq] = PieceC.NO_PIECE;
}
this.st.pawnKey ^= Zobrist.psq[them][PieceTypeC.PAWN][capsq];
}
else
{
if (them == 0)
{
this.st.npMaterialWHITE -= PieceValue[PhaseC.MG][capture];
}
else
{
this.st.npMaterialBLACK -= PieceValue[PhaseC.MG][capture];
}
}
// Remove the captured piece
var capPieceMask = Utils.SquareBB[capsq];
this.occupied_squares ^= capPieceMask;
this.byTypeBB[capture] ^= capPieceMask;
this.byColorBB[them] ^= capPieceMask;
// Update piece list, move the last piece at index[capsq] position and
// shrink the list.
//
// WARNING: This is a not revresible operation. When we will reinsert the
// captured piece in undo_move() we will put it at the end of the list and
// not in its original place, it means index[] and pieceList[] are not
// guaranteed to be invariant to a do_move() + undo_move() sequence.
var plThemCapture = this.pieceList[them][capture];
var pcThemCapture = --this.pieceCount[them][capture];
var lastSquare = plThemCapture[pcThemCapture];
this.index[lastSquare] = this.index[capsq];
plThemCapture[this.index[lastSquare]] = lastSquare;
plThemCapture[pcThemCapture] = SquareC.SQ_NONE;
// Update hash keys
k ^= Zobrist.psq[them][capture][capsq];
this.st.materialKey ^= Zobrist.psq[them][capture][pcThemCapture];
// Update incremental scores
this.st.psqScore -= Zobrist.PieceSquareTable[((them << 3) | capture)][capsq];
// Reset rule 50 counter
this.st.rule50 = 0;
}
// Update hash key
k ^= Zobrist.psq[us][pt][from] ^ Zobrist.psq[us][pt][to];
// Reset en passant square
if (this.st.epSquare != SquareC.SQ_NONE)
{
k ^= Zobrist.enpassant[this.st.epSquare & 7];
this.st.epSquare = SquareC.SQ_NONE;
}
// Update castle rights if needed
if ((this.st.castleRights != 0) && ((this.castleRightsMask[from] | this.castleRightsMask[to]) != 0))
{
var cr = this.castleRightsMask[from] | this.castleRightsMask[to];
k ^= Zobrist.castle[this.st.castleRights & cr];
this.st.castleRights &= ~cr;
}
// Move the piece. The tricky Chess960 castle is handled earlier
if (Utils.type_of_move(m) != MoveTypeC.CASTLING)
{
Bitboard from_to_bb = Utils.SquareBB[from] ^ Utils.SquareBB[to];
occupied_squares ^= from_to_bb;
byTypeBB[pt] ^= from_to_bb;
byColorBB[us] ^= from_to_bb;
board[from] = PieceC.NO_PIECE;
board[to] = piece;
// Update piece lists, index[from] is not updated and becomes stale. This
// works as long as index[] is accessed just by known occupied squares.
index[to] = index[from];
pieceList[us][pt][index[to]] = to;
}
// If the moving piece is a pawn do some special extra work
if (pt == PieceTypeC.PAWN)
{
// Set en-passant square, only if moved pawn can be captured
if ((to ^ from) == 16
&& ((((Utils.StepAttacksBB[((us << 3) | PieceTypeC.PAWN)][
from + (us == ColorC.WHITE ? SquareC.DELTA_N : SquareC.DELTA_S)])
& (this.byTypeBB[PieceTypeC.PAWN] & this.byColorBB[them]))) != 0))
{
this.st.epSquare = ((from + to) / 2);
k ^= Zobrist.enpassant[this.st.epSquare & 7];
}
if (Utils.type_of_move(m) == MoveTypeC.PROMOTION)
{
var promotion = (((m >> 12) & 3) + 2);
Debug.Assert(Utils.relative_rank_CS(us, to) == RankC.RANK_8);
Debug.Assert(promotion >= PieceTypeC.KNIGHT && promotion <= PieceTypeC.QUEEN);
// Replace the pawn with the promoted piece
this.byTypeBB[PieceTypeC.PAWN] ^= Utils.SquareBB[to];
this.byTypeBB[promotion] |= Utils.SquareBB[to];
this.board[to] = ((us << 3) | promotion);
// Update piece lists, move the last pawn at index[to] position
// and shrink the list. Add a new promotion piece to the list.
var plUsPawn = this.pieceList[us][PieceTypeC.PAWN];
var lastSquare = plUsPawn[--this.pieceCount[us][PieceTypeC.PAWN]];
this.index[lastSquare] = this.index[to];
plUsPawn[this.index[lastSquare]] = lastSquare;
plUsPawn[this.pieceCount[us][PieceTypeC.PAWN]] = SquareC.SQ_NONE;
this.index[to] = this.pieceCount[us][promotion];
this.pieceList[us][promotion][this.index[to]] = to;
// Update hash keys
k ^= Zobrist.psq[us][PieceTypeC.PAWN][to] ^ Zobrist.psq[us][promotion][to];
this.st.pawnKey ^= Zobrist.psq[us][PieceTypeC.PAWN][to];
this.st.materialKey ^= Zobrist.psq[us][promotion][this.pieceCount[us][promotion]++]
^ Zobrist.psq[us][PieceTypeC.PAWN][this.pieceCount[us][PieceTypeC.PAWN]];
// Update incremental score
this.st.psqScore += Zobrist.PieceSquareTable[((us << 3) | promotion)][to]
- Zobrist.PieceSquareTable[((us << 3) | PieceTypeC.PAWN)][to];
// Update material
if (us == 0)
{
this.st.npMaterialWHITE += PieceValue[PhaseC.MG][promotion];
}
else
{
this.st.npMaterialBLACK += PieceValue[PhaseC.MG][promotion];
}
}
// Update pawn hash key
this.st.pawnKey ^= Zobrist.psq[us][PieceTypeC.PAWN][from] ^ Zobrist.psq[us][PieceTypeC.PAWN][to];
// Reset rule 50 draw counter
this.st.rule50 = 0;
}
// Update incremental scores
this.st.psqScore += (Zobrist.PieceSquareTable[piece][to] - Zobrist.PieceSquareTable[piece][from]);
// Set capture piece
this.st.capturedType = capture;
// Update the key with the final value
this.st.key = k;
// Update checkers bitboard, piece must be already moved
this.st.checkersBB = 0;
if (moveIsCheck)
{
if (Utils.type_of_move(m) != MoveTypeC.NORMAL)
{
this.st.checkersBB = this.attackers_to(this.pieceList[them][PieceTypeC.KING][0])
& this.byColorBB[us];
}
else
{
// Direct checks
if ((ci.checkSq[pt] & Utils.SquareBB[to]) != 0)
{
this.st.checkersBB |= Utils.SquareBB[to];
}
// Discovery checks
if ((ci.dcCandidates != 0) && ((ci.dcCandidates & Utils.SquareBB[from]) != 0))
{
if (pt != PieceTypeC.ROOK)
{
this.st.checkersBB |= this.attacks_from_ROOK(this.pieceList[them][PieceTypeC.KING][0])
& ((this.byTypeBB[PieceTypeC.ROOK] | this.byTypeBB[PieceTypeC.QUEEN])
& this.byColorBB[us]);
}
if (pt != PieceTypeC.BISHOP)
{
this.st.checkersBB |= this.attacks_from_BISHOP(this.pieceList[them][PieceTypeC.KING][0])
& ((this.byTypeBB[PieceTypeC.BISHOP] | this.byTypeBB[PieceTypeC.QUEEN])
& this.byColorBB[us]);
}
}
}
}
// Finish
this.sideToMove = this.sideToMove ^ 1;
Debug.Assert(this.pos_is_ok());
}
/// move_gives_check() tests whether a pseudo-legal move gives a check
internal bool move_gives_check(int m, CheckInfo ci)
{
Debug.Assert(Utils.is_ok_M(m));
Debug.Assert(ci.dcCandidates == this.discovered_check_candidates());
Debug.Assert(Utils.color_of(this.piece_moved(m)) == this.sideToMove);
var from = (m >> 6) & 0x3F;
var to = m & 0x3F;
var pt = this.board[from] & 7;
// Direct check ?
if ((ci.checkSq[pt] & Utils.SquareBB[to]) != 0)
{
return true;
}
// Discovery check ?
if ((ci.dcCandidates != 0) && ((ci.dcCandidates & Utils.SquareBB[from]) != 0))
{
// For pawn and king moves we need to verify also direction
if ((pt != PieceTypeC.PAWN && pt != PieceTypeC.KING)
|| (((Utils.BetweenBB[from][to]
| Utils.BetweenBB[from][this.pieceList[this.sideToMove ^ 1][PieceTypeC.KING][0]]
| Utils.BetweenBB[to][this.pieceList[this.sideToMove ^ 1][PieceTypeC.KING][0]])
& (Utils.SquareBB[from] | Utils.SquareBB[to]
| Utils.SquareBB[this.pieceList[this.sideToMove ^ 1][PieceTypeC.KING][0]])) == 0))
{
return true;
}
}
// Can we skip the ugly special cases ?
if (Utils.type_of_move(m) == MoveTypeC.NORMAL)
{
return false;
}
var us = this.sideToMove;
var ksq = this.pieceList[this.sideToMove ^ 1][PieceTypeC.KING][0];
switch (Utils.type_of_move(m))
{
case MoveTypeC.PROMOTION:
return (attacks_from((((m >> 12) & 3) + 2), to, this.occupied_squares ^ Utils.SquareBB[from]) & Utils.SquareBB[ksq]) != 0;
// En passant capture with check ? We have already handled the case
// of direct checks and ordinary discovered check, the only case we
// need to handle is the unusual case of a discovered check through
// the captured pawn.
case MoveTypeC.ENPASSANT:
{
var capsq = (((from >> 3) << 3) | (to & 7));
var b = (this.occupied_squares ^ Utils.SquareBB[from] ^ Utils.SquareBB[capsq]) | Utils.SquareBB[to];
return ((Utils.rook_attacks_bb(ksq, b)
& ((this.byTypeBB[PieceTypeC.ROOK] | this.byTypeBB[PieceTypeC.QUEEN]) & this.byColorBB[us]))
!= 0)
|| ((Utils.bishop_attacks_bb(ksq, b)
& ((this.byTypeBB[PieceTypeC.BISHOP] | this.byTypeBB[PieceTypeC.QUEEN]) & this.byColorBB[us]))
!= 0);
}
case MoveTypeC.CASTLING:
if (Utils.type_of_move(m) == MoveTypeC.CASTLING)
{
var kfrom = from;
var rfrom = to; // 'King captures the rook' notation
var kto = ((rfrom > kfrom ? SquareC.SQ_G1 : SquareC.SQ_C1) ^ (us * 56));
var rto = ((rfrom > kfrom ? SquareC.SQ_F1 : SquareC.SQ_D1) ^ (us * 56));
var b = (this.occupied_squares ^ Utils.SquareBB[kfrom] ^ Utils.SquareBB[rfrom]) | Utils.SquareBB[rto]
| Utils.SquareBB[kto];
return (Utils.rook_attacks_bb(rto, b) & Utils.SquareBB[ksq]) != 0;
}
Debug.Assert(false);
return false;
default:
Debug.Assert(false);
return false;
}
}
