static void add_en_passant_captures(list_t * list, const board_t * board) {
int from, to;
int me;
int inc;
int pawn;
ASSERT(list!=NULL);
ASSERT(board!=NULL);
to = board->ep_square;
if (to != SquareNone) {
me = board->turn;
inc = PAWN_MOVE_INC(me);
pawn = PAWN_MAKE(me);
from = to - (inc-1);
if (board->square[from] == pawn) {
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE_FLAGS(from,to,MoveEnPassant));
}
from = to - (inc+1);
if (board->square[from] == pawn) {
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE_FLAGS(from,to,MoveEnPassant));
}
}
}
static void alist_build(alist_t * alist, const board_t * board, int to, int colour) {
const sq_t * ptr;
int from;
int piece;
int delta;
int inc;
int sq;
int pawn;
ASSERT(alist!=NULL);
ASSERT(board!=NULL);
ASSERT(SQUARE_IS_OK(to));
ASSERT(COLOUR_IS_OK(colour));
// piece attacks
for (ptr = &board->piece[colour][0]; (from=*ptr) != SquareNone; ptr++) {
piece = board->square[from];
delta = to - from;
if (PSEUDO_ATTACK(piece,delta)) {
inc = DELTA_INC_ALL(delta);
ASSERT(inc!=IncNone);
sq = from;
do {
sq += inc;
if (sq == to) { // attack
alist_add(alist,from,board);
break;
}
} while (board->square[sq] == Empty);
}
}
// pawn attacks
inc = PAWN_MOVE_INC(colour);
pawn = PAWN_MAKE(colour);
from = to - (inc-1);
if (board->square[from] == pawn) alist_add(alist,from,board);
from = to - (inc+1);
if (board->square[from] == pawn) alist_add(alist,from,board);
}
static bool add_pawn_moves(list_t * list, const board_t * board, int to, bool legal, bool stop) {
int me;
int inc;
int pawn;
int from;
int piece;
ASSERT(list!=NULL);
ASSERT(board!=NULL);
ASSERT(SQUARE_IS_OK(to));
ASSERT(legal==true||legal==false);
ASSERT(stop==true||stop==false);
ASSERT(board->square[to]==Empty);
me = board->turn;
inc = PAWN_MOVE_INC(me);
pawn = PAWN_MAKE(me);
from = to - inc;
piece = board->square[from];
if (piece == pawn) { // single push
if (!legal || !is_pinned(board,from,me)) {
if (stop) return true;
add_pawn_move(list,from,to);
}
} else if (piece == Empty && PAWN_RANK(to,me) == Rank4) { // double push
from = to - (2*inc);
if (board->square[from] == pawn) {
if (!legal || !is_pinned(board,from,me)) {
if (stop) return true;
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
}
return false;
}
bool is_attacked(const board_t * board, int to, int colour) {
int inc;
int pawn;
const sq_t * ptr;
int from;
int piece;
int delta;
int sq;
ASSERT(board!=NULL);
ASSERT(SQUARE_IS_OK(to));
ASSERT(COLOUR_IS_OK(colour));
// pawn attack
inc = PAWN_MOVE_INC(colour);
pawn = PAWN_MAKE(colour);
if (board->square[to-(inc-1)] == pawn) return true;
if (board->square[to-(inc+1)] == pawn) return true;
// piece attack
for (ptr = &board->piece[colour][0]; (from=*ptr) != SquareNone; ptr++) {
piece = board->square[from];
delta = to - from;
if (PSEUDO_ATTACK(piece,delta)) {
inc = DELTA_INC_ALL(delta);
ASSERT(inc!=IncNone);
sq = from;
do {
sq += inc;
if (sq == to) return true;
} while (board->square[sq] == Empty);
}
}
return false;
}
void board_from_fen(board_t * board, const char fen[]) {
int pos;
int file, rank, sq;
int c;
int i, len;
int piece;
int pawn;
ASSERT(board!=NULL);
ASSERT(fen!=NULL);
board_clear(board);
pos = 0;
c = fen[pos];
// piece placement
for (rank = Rank8; rank >= Rank1; rank--) {
for (file = FileA; file <= FileH;) {
if (c >= '1' && c <= '8') { // empty square(s)
len = c - '0';
for (i = 0; i < len; i++) {
if (file > FileH) my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
board->square[SQUARE_MAKE(file,rank)] = Empty;
file++;
}
} else { // piece
piece = piece_from_char(c);
if (piece == PieceNone256) my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
board->square[SQUARE_MAKE(file,rank)] = piece;
file++;
}
c = fen[++pos];
}
if (rank > Rank1) {
if (c != '/') my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
c = fen[++pos];
}
}
// active colour
if (c != ' ') my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
c = fen[++pos];
switch (c) {
case 'w':
board->turn = White;
break;
case 'b':
board->turn = Black;
break;
default:
my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
break;
}
c = fen[++pos];
// castling
if (c != ' ') my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
c = fen[++pos];
board->flags = FlagsNone;
if (c == '-') { // no castling rights
c = fen[++pos];
} else {
if (c == 'K') {
if (board->square[E1] == WK && board->square[H1] == WR) board->flags |= FlagsWhiteKingCastle;
c = fen[++pos];
}
if (c == 'Q') {
if (board->square[E1] == WK && board->square[A1] == WR) board->flags |= FlagsWhiteQueenCastle;
c = fen[++pos];
}
if (c == 'k') {
if (board->square[E8] == BK && board->square[H8] == BR) board->flags |= FlagsBlackKingCastle;
c = fen[++pos];
}
if (c == 'q') {
if (board->square[E8] == BK && board->square[A8] == BR) board->flags |= FlagsBlackQueenCastle;
c = fen[++pos];
}
}
// en-passant
if (c != ' ') my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
c = fen[++pos];
if (c == '-') { // no en-passant
sq = SquareNone;
c = fen[++pos];
} else {
if (c < 'a' || c > 'h') my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
file = file_from_char(c);
c = fen[++pos];
if (c != (COLOUR_IS_WHITE(board->turn) ? '6' : '3')) my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
rank = rank_from_char(c);
c = fen[++pos];
sq = SQUARE_MAKE(file,rank);
pawn = SQUARE_EP_DUAL(sq);
if (board->square[sq] != Empty
|| board->square[pawn] != PAWN_MAKE(COLOUR_OPP(board->turn))
|| (board->square[pawn-1] != PAWN_MAKE(board->turn)
&& board->square[pawn+1] != PAWN_MAKE(board->turn))) {
sq = SquareNone;
}
}
board->ep_square = sq;
// halfmove clock
board->ply_nb = 0;
if (c != ' ') {
if (!Strict) goto update;
my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
}
c = fen[++pos];
if (!isdigit(c)) {
if (!Strict) goto update;
my_fatal("board_from_fen(): bad FEN (pos=%d)\n",pos);
}
board->ply_nb = atoi(&fen[pos]);
// board update
update:
board_init_list(board);
}
static bool add_pawn_captures(list_t * list, const board_t * board, int to, bool legal, bool stop) {
int me;
int inc;
int pawn;
int from;
ASSERT(list!=NULL);
ASSERT(board!=NULL);
ASSERT(SQUARE_IS_OK(to));
ASSERT(legal==true||legal==false);
ASSERT(stop==true||stop==false);
ASSERT(COLOUR_IS(board->square[to],COLOUR_OPP(board->turn)));
me = board->turn;
inc = PAWN_MOVE_INC(me);
pawn = PAWN_MAKE(me);
from = to - (inc-1);
if (board->square[from] == pawn) {
if (!legal || !is_pinned(board,from,me)) {
if (stop) return true;
add_pawn_move(list,from,to);
}
}
from = to - (inc+1);
if (board->square[from] == pawn) {
if (!legal || !is_pinned(board,from,me)) {
if (stop) return true;
add_pawn_move(list,from,to);
}
}
if (board->ep_square != SquareNone
&& to == SQUARE_EP_DUAL(board->ep_square)) {
ASSERT(PAWN_RANK(to,me)==Rank5);
ASSERT(PIECE_IS_PAWN(board->square[to]));
to = board->ep_square;
ASSERT(PAWN_RANK(to,me)==Rank6);
ASSERT(board->square[to]==Empty);
from = to - (inc-1);
if (board->square[from] == pawn) {
if (!legal || !is_pinned(board,from,me)) {
if (stop) return true;
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE_FLAGS(from,to,MoveEnPassant));
}
}
from = to - (inc+1);
if (board->square[from] == pawn) {
if (!legal || !is_pinned(board,from,me)) {
if (stop) return true;
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE_FLAGS(from,to,MoveEnPassant));
}
}
}
return false;
}
static void add_quiet_checks(list_t * list, const board_t * board) {
int me, opp;
int king;
const sq_t * ptr, * ptr_2;
int from, to, sq;
int piece;
const inc_t * inc_ptr;
int inc;
int pawn;
int rank;
int pin[8+1];
ASSERT(list!=NULL);
ASSERT(board!=NULL);
// init
me = board->turn;
opp = COLOUR_OPP(me);
king = KING_POS(board,opp);
find_pins(pin,board);
// indirect checks
for (ptr = pin; (from=*ptr) != SquareNone; ptr++) {
piece = board->square[from];
ASSERT(is_pinned(board,from,opp));
if (PIECE_IS_PAWN(piece)) {
inc = PAWN_MOVE_INC(me);
rank = PAWN_RANK(from,me);
if (rank != Rank7) { // promotes are generated with captures
to = from + inc;
if (board->square[to] == Empty) {
if (DELTA_INC_LINE(to-king) != DELTA_INC_LINE(from-king)) {
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE(from,to));
if (rank == Rank2) {
to = from + (2*inc);
if (board->square[to] == Empty) {
ASSERT(DELTA_INC_LINE(to-king)!=DELTA_INC_LINE(from-king));
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
}
}
}
} else if (PIECE_IS_SLIDER(piece)) {
for (inc_ptr = PIECE_INC(piece); (inc=*inc_ptr) != IncNone; inc_ptr++) {
for (to = from+inc; board->square[to] == Empty; to += inc) {
ASSERT(DELTA_INC_LINE(to-king)!=DELTA_INC_LINE(from-king));
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
} else {
for (inc_ptr = PIECE_INC(piece); (inc=*inc_ptr) != IncNone; inc_ptr++) {
to = from + inc;
if (board->square[to] == Empty) {
if (DELTA_INC_LINE(to-king) != DELTA_INC_LINE(from-king)) {
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
}
}
}
// piece direct checks
for (ptr = &board->piece[me][1]; (from=*ptr) != SquareNone; ptr++) { // HACK: no king
for (ptr_2 = pin; (sq=*ptr_2) != SquareNone; ptr_2++) {
if (sq == from) goto next_piece;
}
ASSERT(!is_pinned(board,from,opp));
piece = board->square[from];
inc_ptr = PIECE_INC(piece);
if (PIECE_IS_SLIDER(piece)) {
for (; (inc=*inc_ptr) != IncNone; inc_ptr++) {
for (to = from+inc; board->square[to] == Empty; to += inc) {
if (PIECE_ATTACK(board,piece,to,king)) {
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
}
} else {
for (; (inc=*inc_ptr) != IncNone; inc_ptr++) {
to = from + inc;
if (board->square[to] == Empty) {
if (PSEUDO_ATTACK(piece,king-to)) {
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
}
}
next_piece:
;
}
// pawn direct checks
inc = PAWN_MOVE_INC(me);
pawn = PAWN_MAKE(me);
to = king - (inc-1);
ASSERT(PSEUDO_ATTACK(pawn,king-to));
from = to - inc;
if (board->square[from] == pawn) {
if (board->square[to] == Empty) {
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE(from,to));
}
} else {
from = to - (2*inc);
if (board->square[from] == pawn) {
if (PAWN_RANK(from,me) == Rank2
&& board->square[to] == Empty
&& board->square[from+inc] == Empty) {
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
}
to = king - (inc+1);
ASSERT(PSEUDO_ATTACK(pawn,king-to));
from = to - inc;
if (board->square[from] == pawn) {
if (board->square[to] == Empty) {
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE(from,to));
}
} else {
from = to - (2*inc);
if (board->square[from] == pawn) {
if (PAWN_RANK(from,me) == Rank2
&& board->square[to] == Empty
&& board->square[from+inc] == Empty) {
ASSERT(!SQUARE_IS_PROMOTE(to));
LIST_ADD(list,MOVE_MAKE(from,to));
}
}
}
}
void move_do(board_t * board, int move, undo_t * undo) {
int me, opp;
int from, to;
int piece, pos, capture;
int old_flags, new_flags;
int delta;
int sq;
int pawn, rook;
ASSERT(board!=NULL);
ASSERT(move_is_ok(move));
ASSERT(undo!=NULL);
ASSERT(board_is_legal(board));
// initialise undo
undo->capture = false;
undo->turn = board->turn;
undo->flags = board->flags;
undo->ep_square = board->ep_square;
undo->ply_nb = board->ply_nb;
undo->cap_sq = board->cap_sq;
undo->opening = board->opening;
undo->endgame = board->endgame;
undo->key = board->key;
undo->pawn_key = board->pawn_key;
undo->material_key = board->material_key;
// init
me = board->turn;
opp = COLOUR_OPP(me);
from = MOVE_FROM(move);
to = MOVE_TO(move);
piece = board->square[from];
ASSERT(COLOUR_IS(piece,me));
// update key stack
ASSERT(board->sp<StackSize);
board->stack[board->sp++] = board->key;
// update turn
board->turn = opp;
board->key ^= RANDOM_64(RandomTurn);
// update castling rights
old_flags = board->flags;
new_flags = old_flags & CastleMask[from] & CastleMask[to];
board->flags = new_flags;
board->key ^= Castle64[new_flags^old_flags]; // HACK
// update en-passant square
if ((sq=board->ep_square) != SquareNone) {
board->key ^= RANDOM_64(RandomEnPassant+SQUARE_FILE(sq)-FileA);
board->ep_square = SquareNone;
}
if (PIECE_IS_PAWN(piece)) {
delta = to - from;
if (delta == +32 || delta == -32) {
pawn = PAWN_MAKE(opp);
if (board->square[to-1] == pawn || board->square[to+1] == pawn) {
board->ep_square = (from + to) / 2;
board->key ^= RANDOM_64(RandomEnPassant+SQUARE_FILE(to)-FileA);
}
}
}
// update move number (captures are handled later)
board->ply_nb++;
if (PIECE_IS_PAWN(piece)) board->ply_nb = 0; // conversion
// update last square
board->cap_sq = SquareNone;
// remove the captured piece
sq = to;
if (MOVE_IS_EN_PASSANT(move)) sq = SQUARE_EP_DUAL(sq);
if ((capture=board->square[sq]) != Empty) {
ASSERT(COLOUR_IS(capture,opp));
ASSERT(!PIECE_IS_KING(capture));
undo->capture = true;
undo->capture_square = sq;
undo->capture_piece = capture;
undo->capture_pos = board->pos[sq];
square_clear(board,sq,capture,true);
board->ply_nb = 0; // conversion
board->cap_sq = to;
}
// move the piece
if (MOVE_IS_PROMOTE(move)) {
// promote
undo->pawn_pos = board->pos[from];
square_clear(board,from,piece,true);
piece = move_promote(move);
// insert the promote piece in MV order
for (pos = board->piece_size[me]; pos > 0 && piece > board->square[board->piece[me][pos-1]]; pos--) // HACK
;
square_set(board,to,piece,pos,true);
board->cap_sq = to;
} else {
// normal move
square_move(board,from,to,piece,true);
}
// move the rook in case of castling
if (MOVE_IS_CASTLE(move)) {
rook = Rook64 | COLOUR_FLAG(me); // HACK
if (to == G1) {
square_move(board,H1,F1,rook,true);
} else if (to == C1) {
square_move(board,A1,D1,rook,true);
} else if (to == G8) {
square_move(board,H8,F8,rook,true);
} else if (to == C8) {
square_move(board,A8,D8,rook,true);
} else {
ASSERT(false);
}
}
// debug
ASSERT(board_is_ok(board));
}
void move_undo(board_t * board, int move, const undo_t * undo) {
int me;
int from, to;
int piece, pos;
int rook;
ASSERT(board!=NULL);
ASSERT(move_is_ok(move));
ASSERT(undo!=NULL);
// init
me = undo->turn;
from = MOVE_FROM(move);
to = MOVE_TO(move);
piece = board->square[to];
ASSERT(COLOUR_IS(piece,me));
// castle
if (MOVE_IS_CASTLE(move)) {
rook = Rook64 | COLOUR_FLAG(me); // HACK
if (to == G1) {
square_move(board,F1,H1,rook,false);
} else if (to == C1) {
square_move(board,D1,A1,rook,false);
} else if (to == G8) {
square_move(board,F8,H8,rook,false);
} else if (to == C8) {
square_move(board,D8,A8,rook,false);
} else {
ASSERT(false);
}
}
// move the piece backward
if (MOVE_IS_PROMOTE(move)) {
// promote
ASSERT(piece==move_promote(move));
square_clear(board,to,piece,false);
piece = PAWN_MAKE(me);
pos = undo->pawn_pos;
square_set(board,from,piece,pos,false);
} else {
// normal move
square_move(board,to,from,piece,false);
}
// put the captured piece back
if (undo->capture) {
square_set(board,undo->capture_square,undo->capture_piece,undo->capture_pos,false);
}
// update board info
board->turn = undo->turn;
board->flags = undo->flags;
board->ep_square = undo->ep_square;
board->ply_nb = undo->ply_nb;
board->cap_sq = undo->cap_sq;
board->opening = undo->opening;
board->endgame = undo->endgame;
board->key = undo->key;
board->pawn_key = undo->pawn_key;
board->material_key = undo->material_key;
// update key stack
ASSERT(board->sp>0);
board->sp--;
// debug
ASSERT(board_is_ok(board));
ASSERT(board_is_legal(board));
}
void attack_set(attack_t * attack, const board_t * board) {
int me, opp;
const sq_t * ptr;
int from, to;
int inc;
int pawn;
int delta, piece;
int sq;
ASSERT(attack!=NULL);
ASSERT(board!=NULL);
// init
attack->dn = 0;
me = board->turn;
opp = COLOUR_OPP(me);
to = KING_POS(board,me);
// pawn attacks
inc = PAWN_MOVE_INC(opp);
pawn = PAWN_MAKE(opp);
from = to - (inc-1);
if (board->square[from] == pawn) {
attack->ds[attack->dn] = from;
attack->di[attack->dn] = IncNone;
attack->dn++;
}
from = to - (inc+1);
if (board->square[from] == pawn) {
attack->ds[attack->dn] = from;
attack->di[attack->dn] = IncNone;
attack->dn++;
}
// piece attacks
for (ptr = &board->piece[opp][1]; (from=*ptr) != SquareNone; ptr++) { // HACK: no king
piece = board->square[from];
delta = to - from;
ASSERT(delta_is_ok(delta));
if (PSEUDO_ATTACK(piece,delta)) {
inc = IncNone;
if (PIECE_IS_SLIDER(piece)) {
// check for blockers
inc = DELTA_INC_LINE(delta);
ASSERT(inc!=IncNone);
sq = from;
do sq += inc; while (board->square[sq] == Empty);
if (sq != to) continue; // blocker => next attacker
}
attack->ds[attack->dn] = from;
attack->di[attack->dn] = -inc; // HACK
attack->dn++;
}
}
attack->ds[attack->dn] = SquareNone;
attack->di[attack->dn] = IncNone;
// debug
ASSERT(attack_is_ok(attack));
}
