int __generateSimpleMove(ChessMoveGenerator* self, ChessPiece* piece,
int dRank, int dFile, int validate){
//returns 1 if the move was succesfull,
//0 if it failed because of check,
//and -1 if it failed because it was out of bounds/blocked
ChessPiece* capture;
int rank, file;
location_t to;
move_t move;
rank = GET_RANK(piece->location)+dRank;
file = GET_FILE(piece->location)+dFile;
//if the move is in the board (0<=rank<8)&&(0<=file<8)
if(((rank&7)==rank) && ((file&7)==file)){
to = RANK_FILE(rank,file);
move = NEW_MOVE(piece->location, to);
capture = self->board->squares[to];
if((capture!=NULL) && ((capture->color) != (self->toPlay)))
move|=CAPTURE_MOVE_FLAG;
else if(capture!=NULL)
return -1; //the same color
ChessBoard_makeMove(self->board, move);
if(__finalizeAndUndo(self, validate)) return 1;
else return 0;
}
return -1;
}
char __getChar(ChessBoard* self, location_t loc){
assert(self!=NULL);
assert(0<=loc);
assert(loc<64);
ChessPiece* piece = self->squares[loc];
if(piece==NULL)
return ((GET_RANK(loc)^GET_FILE(loc))%2)?' ':'+';
return __getPieceChar(piece);
}
void __generatePawnMoves(ChessMoveGenerator* self){
int i, rank, file;
assert(self!=NULL);
assert(self->curSet!=NULL);
int size = self->curSet->piecesCounts[PAWN_INDEX];
int pawnDirection = self->toPlay==WHITE?1:-1;
int pawnHomeRank = self->toPlay==WHITE?1:6;
int lastRank = self->toPlay==WHITE?6:1;
ChessPiece* pawn;
move_t move;
location_t to;
//since the order of the pawns might change in the set
//durring operations, we must store a local copy
ChessPiece** pawns = (ChessPiece**)malloc(
sizeof(ChessPiece*)*size);
memcpy(pawns, self->curSet->piecesByType[PAWN_INDEX],
sizeof(ChessPiece*)*size);
for(i=0;i<size;i++){
pawn = pawns[i];
rank = GET_RANK(pawn->location);
file = GET_FILE(pawn->location);
//try to move forward
to = RANK_FILE(rank+pawnDirection, file);
if(self->board->squares[to]==NULL){
move = NEW_MOVE(pawn->location,to);
if(rank==lastRank){
//generate promotions
__generatePawnPromotions(self, move);
}
else{
//generate regular forward push
ChessBoard_makeMove(self->board, move);
if((__finalizeAndUndo(self, 1)||self->inCheck)
&& pawnHomeRank==rank){
to = RANK_FILE(rank+pawnDirection*2, file);
if(self->board->squares[to]==NULL){
move = NEW_MOVE(pawn->location,to);
move|=DOUBLE_PAWN_PUSH_MOVE;
ChessBoard_makeMove(self->board, move);
__finalizeAndUndo(self, self->inCheck);
}
}
}
}
if(file>0){//try to capture left
__generatePawnCapture(self, rank, file, pawnDirection, -1,
lastRank);
}
if(file<7){//try to capture right
__generatePawnCapture(self, rank, file, pawnDirection, 1,
lastRank);
}
}//end for
free(pawns);
}
//Initializes pawn eval masks
void Init_Pawn_Masks(void)
{
int index,rank,file,rank_index,file_index;
//Clear all masks;
for (index = 0; index < 64; index++)
{
white_passed_masks[index] = 0;
black_passed_masks[index] = 0;
isolated_masks[index] = 0;
doubled_masks[index] = 0;
}
//For each square on the board
for (index = 0; index < 64; index++)
{
rank = GET_RANK(index);
file = GET_FILE(index);
for (rank_index = RANK_1; rank_index <= RANK_8; rank_index++)
{
for (file_index = FILE_A; file_index <= FILE_H; file_index++)
{
//white passed mask
//If file is neighboring and space is above index
if (abs(file - file_index) <= 1 && rank_index > rank)
{
SET_BIT(white_passed_masks[index], RANK_FILE_TO_SQUARE(rank_index, file_index));
}
//black passed mask
//If file is neighboring and space is below index
if (abs(file - file_index) <= 1 && rank_index < rank)
{
SET_BIT(black_passed_masks[index], RANK_FILE_TO_SQUARE(rank_index, file_index));
}
//isolated mask
//If file is neighboring and space is not equal to index
if (abs(file - file_index) <= 1 && (file != file_index || rank != rank_index))
{
SET_BIT(isolated_masks[index], RANK_FILE_TO_SQUARE(rank_index, file_index));
}
//Doubled mask
//If file is the same and rank is different
if (file == file_index && rank != rank_index)
{
SET_BIT(doubled_masks[index], RANK_FILE_TO_SQUARE(rank_index, file_index));
}
}
}
}
}
void __generateDirectionalMoves(ChessMoveGenerator* self,
ChessPiece* piece, int dRank, int dFile){
ChessPiece* capture;
int rank, file;
rank = GET_RANK(piece->location)+dRank;
file = GET_FILE(piece->location)+dFile;
int validated = 0;
location_t to;
move_t move;
//while inside the board (0<=rank<8 && 0<=file<8)
while(((rank&7)==rank) && ((file&7)==file)){
to = RANK_FILE(rank,file);
capture = self->board->squares[to];
if(capture==NULL){
move = NEW_MOVE(piece->location, to);
ChessBoard_makeMove(self->board, move);
if(__finalizeAndUndo(self, (!validated)||self->inCheck)){
if(self->inCheck)
break; //move blocks some directional check,
//any further move in this direction
//will not.
validated = 1;
}
else if(!self->inCheck){
break; //move puts you in check, any move in
//this direction will also put you in check
}
}
else if(capture->color != self->toPlay){
move = NEW_MOVE(piece->location, to)|CAPTURE_MOVE_FLAG;
ChessBoard_makeMove(self->board, move);
__finalizeAndUndo(self, self->inCheck||(!validated));
break;
}
else break; //you hit your own piece
rank+=dRank;
file+=dFile;
}
}
void ChessBoard_makeMove(ChessBoard* self, move_t move){
//push the move onto the move stack
GameInfo* info = (GameInfo*)self->extra;
BoardBackup* backup = &(info->backups[info->movesCount]);
backup->hash = self->hash;
backup->flags = self->flags;
backup->fiftyMoveCount = self->fiftyMoveCount;
info->moves[info->movesCount++] = move;
if(self->flags&TO_PLAY_FLAG) //black
self->fiftyMoveCount++;
__toggleToPlay(self);
__clearEnPassantFlags(self);
int meta = GET_META(move);
location_t from = GET_FROM(move);
location_t to = GET_TO(move);
if((self->squares[from]->type==PAWN) || (meta&CAPTURE_MOVE_FLAG))
self->fiftyMoveCount=0;
int rank, file;
//do special moves
switch(meta){
case DOUBLE_PAWN_PUSH_MOVE:
__setEnPassantFlags(self, GET_FILE(to));
break;
case KING_CASTLE_MOVE:
case QUEEN_CASTLE_MOVE:
rank = GET_RANK(from);
if(meta==KING_CASTLE_MOVE)
__movePieceByLoc(self,
RANK_FILE(rank, 7), RANK_FILE(rank, 5));
else
__movePieceByLoc(self,
RANK_FILE(rank, 0), RANK_FILE(rank, 3));
if(rank==0){//white
__unsetCastleFlag(self, WHITE_KING_CASTLE_FLAG);
__unsetCastleFlag(self, WHITE_QUEEN_CASTLE_FLAG);
}
else{//black
__unsetCastleFlag(self, BLACK_KING_CASTLE_FLAG);
__unsetCastleFlag(self, BLACK_QUEEN_CASTLE_FLAG);
}
break;
case EN_PASSANT_MOVE:
rank = GET_RANK(from);
file = GET_FILE(to);
__capturePiece(self,
self->squares[RANK_FILE(rank,file)]);
break;
default:
if(meta&CAPTURE_MOVE_FLAG){
ChessPiece* captured = self->squares[to];
__capturePiece(self, captured);
if(captured->type==ROOK){
switch(to){
case WHITE_QUEEN_ROOK_START:
__unsetCastleFlag(self, WHITE_QUEEN_CASTLE_FLAG);
break;
case WHITE_KING_ROOK_START:
__unsetCastleFlag(self, WHITE_KING_CASTLE_FLAG);
break;
case BLACK_QUEEN_ROOK_START:
__unsetCastleFlag(self, BLACK_QUEEN_CASTLE_FLAG);
break;
case BLACK_KING_ROOK_START:
__unsetCastleFlag(self, BLACK_KING_CASTLE_FLAG);
break;
}
}
}
if(meta&PROMOTION_MOVE_FLAG){
ChessPiece* piece = self->squares[from];
__removePiece(self, piece);
switch(meta&PROMOTION_MASK){
case QUEEN_PROMOTION:
piece->type=QUEEN;
break;
case ROOK_PROMOTION:
piece->type=ROOK;
break;
case KNIGHT_PROMOTION:
piece->type=KNIGHT;
break;
case BISHOP_PROMOTION:
piece->type=BISHOP;
break;
default:
assert(0);
}
__addPiece(self, piece);
}
}
if(meta==0 || meta==CAPTURE_MOVE_FLAG){
switch(from){
case WHITE_QUEEN_ROOK_START:
__unsetCastleFlag(self, WHITE_QUEEN_CASTLE_FLAG);
break;
case WHITE_KING_ROOK_START:
__unsetCastleFlag(self, WHITE_KING_CASTLE_FLAG);
break;
case WHITE_KING_START:
__unsetCastleFlag(self, WHITE_QUEEN_CASTLE_FLAG);
__unsetCastleFlag(self, WHITE_KING_CASTLE_FLAG);
break;
case BLACK_QUEEN_ROOK_START:
__unsetCastleFlag(self, BLACK_QUEEN_CASTLE_FLAG);
break;
case BLACK_KING_ROOK_START:
__unsetCastleFlag(self, BLACK_KING_CASTLE_FLAG);
break;
case BLACK_KING_START:
__unsetCastleFlag(self, BLACK_QUEEN_CASTLE_FLAG);
__unsetCastleFlag(self, BLACK_KING_CASTLE_FLAG);
break;
}
}
__movePieceByLoc(self, from, to);
}
void toAlgebraicNotation(move_t move, ChessBoard* board, char* out, int* outSize){
location_t from = GET_FROM(move);
location_t to = GET_TO(move);
int meta = GET_META(move);
int i = 0;
ChessBoard_makeMove(board, move);
int isInCheck = ChessBoard_testForCheck(board);
ChessMoveGenerator* gen = ChessMoveGenerator_new(board);
ChessMoveGenerator_generateMoves(gen, isInCheck, NULL);
int isInCheckmate = isInCheck&&(gen->nextCount==0);
ChessBoard_unmakeMove(board);
ChessMoveGenerator_generateMoves(gen, ChessBoard_testForCheck(board), NULL);
if(meta==KING_CASTLE_MOVE){
char* notation = "O-O";
for(i = 0; i < 3; i++)
out[i] = notation[i];
}
else if(meta==QUEEN_CASTLE_MOVE){
char* notation = "O-O-O";
for(i = 0; i < 5; i++)
out[i] = notation[i];
}
else{
//write piece indicator
ChessPiece* piece = board->squares[from];
if(piece->type==KING)
out[i++] = 'K';
else{
//for each other move,
//check to see if there are multiple pieces
//of this piece's type that can move to the 'to' square.
int j;
move_t otherMoves[20];
int otherMovesCount = 0;
move_t otherMove;
for(j = 0; j < gen->nextCount; j++){
otherMove = gen->next[j];
if((GET_TO(otherMove)==to) &&
(GET_FROM(otherMove)!=from) &&
(board->squares[GET_FROM(otherMove)]->type==
piece->type)){
if(piece->type==PAWN &&
(move&CAPTURE_MOVE_FLAG)!=
(otherMove&CAPTURE_MOVE_FLAG))
continue;
if(otherMove==move)
continue;
otherMoves[otherMovesCount++] = otherMove;
}
}
//note if there are multiple moves
//from the same rank or file
int sameRank = 0, sameFile = 0;
for(j = 0; j < otherMovesCount; j++){
otherMove = otherMoves[j];
if(GET_RANK(from)==GET_RANK(GET_FROM(otherMove)))
sameRank = 1;
if(GET_FILE(from)==GET_FILE(GET_FROM(otherMove)))
sameFile = 1;
}
if(piece->type!=PAWN)
out[i++] = __pieceTypeToChar(piece->type);
else if(meta&CAPTURE_MOVE_FLAG)
out[i++] = __fileToChar(GET_FILE(from));
if(piece->type!=PAWN && otherMovesCount){
if(!sameFile)
out[i++] = __fileToChar(GET_FILE(from));
else if(!sameRank)
out[i++] = __rankToChar(GET_RANK(from));
else{
out[i++] = __fileToChar(GET_FILE(from));
out[i++] = __rankToChar(GET_RANK(from));
}
}
}
//if capture
if(meta&CAPTURE_MOVE_FLAG)
out[i++] = 'x';
//write destination
out[i++] = __fileToChar(GET_FILE(to));
out[i++] = __rankToChar(GET_RANK(to));
if(meta&PROMOTION_MOVE_FLAG){
out[i++] = '=';
switch(meta&PROMOTION_MASK){
case KNIGHT_PROMOTION:
out[i++] = 'N';
break;
case BISHOP_PROMOTION:
out[i++] = 'B';
break;
case ROOK_PROMOTION:
out[i++] = 'R';
break;
case QUEEN_PROMOTION:
out[i++] = 'Q';
break;
default:
assert(0);
}
}
}
if(isInCheckmate)
out[i++] = '#';
else if(isInCheck)
out[i++] = '+';
out[i] = '\0';
(*outSize) = i;
ChessMoveGenerator_delete(gen);
}
int __testForCheck(ChessBoard* board, color_e color){
GameInfo* info = (GameInfo*)board->extra;
ChessPieceSet* pieces = info->pieceSets[color];
ChessPieceSet* opPieces = info->pieceSets[OTHER_COLOR(color)];
ChessPiece* king = pieces->piecesByType[TYPE_TO_INT(KING)][0];
int kingRank, kingFile;
kingRank = GET_RANK(king->location);
kingFile = GET_FILE(king->location);
//test for check by a pawn
if((color==WHITE && kingRank<6) || (color==BLACK && kingRank>1)){
int opPawnDirection = color==WHITE?-1:1;
int pawnRank = kingRank-opPawnDirection;
ChessPiece* pawn;
if(kingFile>0){
pawn = board->squares[RANK_FILE(pawnRank, kingFile-1)];
if((pawn!=NULL) && (pawn->type==PAWN) &&
(pawn->color!=color)){
return 1;
}
}
if(kingFile<7){
pawn = board->squares[RANK_FILE(pawnRank, kingFile+1)];
if((pawn!=NULL) && (pawn->type==PAWN) &&
(pawn->color!=color)){
return 1;
}
}
}
//test for check by knight
int i, rankDelta, fileDelta, rank, file;
int size = opPieces->piecesCounts[KNIGHT_INDEX];
ChessPiece* knight;
for(i=0; i<size; i++){
knight = opPieces->piecesByType[KNIGHT_INDEX][i];
rankDelta = kingRank-GET_RANK(knight->location);
fileDelta = kingFile-GET_FILE(knight->location);
if((rankDelta*rankDelta+fileDelta*fileDelta)==5)
return 1;
}
//test for check by bishop
size = opPieces->piecesCounts[BISHOP_INDEX];
ChessPiece* bishop;
for(i=0; i<size; i++){
bishop = opPieces->piecesByType[BISHOP_INDEX][i];
rankDelta = kingRank-GET_RANK(bishop->location);
fileDelta = kingFile-GET_FILE(bishop->location);
if(rankDelta*rankDelta == fileDelta*fileDelta){
//the king is on a diagonal with this opposing bishop
//check every square inbetween to see if the bishop
//is blocked
assert(rankDelta!=0);
rankDelta = rankDelta>0?1:-1;
fileDelta = fileDelta>0?1:-1;
rank = GET_RANK(bishop->location)+rankDelta;
file = GET_FILE(bishop->location)+fileDelta;
while(rank!=kingRank){
if(board->squares[RANK_FILE(rank,file)]!=NULL)
break;
rank+=rankDelta;
file+=fileDelta;
}
if(rank==kingRank)
return 1;
}
}
//test for check by rook
size = opPieces->piecesCounts[TYPE_TO_INT(ROOK)];
ChessPiece* rook;
for(i=0; i<size; i++){
rook = opPieces->piecesByType[TYPE_TO_INT(ROOK)][i];
rankDelta = kingRank-GET_RANK(rook->location);
fileDelta = kingFile-GET_FILE(rook->location);
if((rankDelta == 0)||(fileDelta == 0)){
//the king is on a rank or a file with this opposing rook
//check every square inbetween to see if the rook
//is blocked
if(fileDelta!=0) fileDelta = fileDelta>0?1:-1;
if(rankDelta!=0) rankDelta = rankDelta>0?1:-1;
rank = GET_RANK(rook->location)+rankDelta;
file = GET_FILE(rook->location)+fileDelta;
while(rank!=kingRank || file!=kingFile){
if(board->squares[RANK_FILE(rank,file)]!=NULL)
break;
rank+=rankDelta;
file+=fileDelta;
}
if(rank==kingRank && file==kingFile){
return 1;
}
}
}
//test for check by queen
size = opPieces->piecesCounts[TYPE_TO_INT(QUEEN)];
ChessPiece* queen;
for(i=0; i<size; i++){
queen = opPieces->piecesByType[TYPE_TO_INT(QUEEN)][i];
rankDelta = kingRank-GET_RANK(queen->location);
fileDelta = kingFile-GET_FILE(queen->location);
if((rankDelta*rankDelta == fileDelta*fileDelta)||
(rankDelta == 0)||(fileDelta == 0)){
//the king is on a diagonal, rank or file with
//this opposing queen, check every square
//inbetween to see if the queen is blocked
if(fileDelta!=0) fileDelta = fileDelta>0?1:-1;
if(rankDelta!=0) rankDelta = rankDelta>0?1:-1;
rank = GET_RANK(queen->location)+rankDelta;
file = GET_FILE(queen->location)+fileDelta;
while(rank!=kingRank || file!=kingFile){
if(board->squares[RANK_FILE(rank,file)]!=NULL){
break;
}
rank+=rankDelta;
file+=fileDelta;
}
if(rank==kingRank && file==kingFile){
return 1;
}
}
}
//test for check by other king
//for hypothetical moves that are blocked
//by the opposing king
ChessPiece* opKing = opPieces->piecesByType[TYPE_TO_INT(KING)][0];
rankDelta = kingRank-GET_RANK(opKing->location);
fileDelta = kingFile-GET_FILE(opKing->location);
if((rankDelta*rankDelta+fileDelta*fileDelta)<=2){
return 1;
}
//Otherwise, the king is not in check
return 0;
}
//Looks at pawn shielding around each king and returns white - black score
int Get_King_Safety_Score(BOARD_STRUCT *board)
{
int white_score = 0;
int black_score = 0;
U64 temp = board->piece_bitboards[wK];
int white_king_square = pop_1st_bit(&temp);
temp = board->piece_bitboards[bK];
int black_king_square = pop_1st_bit(&temp);
//White king on kingside
if (GET_FILE(white_king_square) > FILE_E && GET_RANK(white_king_square) == RANK_1) {
if (board->board_array[F2] == wP) white_score += PAWN_SHIELD_SCORE;
else if (board->board_array[F3] == wP) white_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[G2] == wP) white_score += PAWN_SHIELD_SCORE;
else if (board->board_array[G3] == wP) white_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[H2] == wP) white_score += PAWN_SHIELD_SCORE;
else if (board->board_array[H3] == wP) white_score += PAWN_SHIELD_SCORE / 2;
}
else if (GET_FILE(white_king_square) < FILE_D && GET_RANK(white_king_square) == RANK_1) {
if (board->board_array[A2] == wP) white_score += PAWN_SHIELD_SCORE;
else if (board->board_array[A3] == wP) white_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[B2] == wP) white_score += PAWN_SHIELD_SCORE;
else if (board->board_array[B3] == wP) white_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[C2] == wP) white_score += PAWN_SHIELD_SCORE;
else if (board->board_array[C3] == wP) white_score += PAWN_SHIELD_SCORE / 2;
}
//Black king on kingside
if (GET_FILE(black_king_square) > FILE_E && GET_RANK(black_king_square) == RANK_8) {
if (board->board_array[F7] == bP) black_score += PAWN_SHIELD_SCORE;
else if (board->board_array[F6] == bP) black_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[G7] == bP) black_score += PAWN_SHIELD_SCORE;
else if (board->board_array[G6] == bP) black_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[H7] == bP) black_score += PAWN_SHIELD_SCORE;
else if (board->board_array[H6] == bP) black_score += PAWN_SHIELD_SCORE / 2;
}
else if (GET_FILE(black_king_square) < FILE_D && GET_RANK(black_king_square) == RANK_8) {
if (board->board_array[A7] == bP) black_score += PAWN_SHIELD_SCORE;
else if (board->board_array[A6] == bP) black_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[B7] == bP) black_score += PAWN_SHIELD_SCORE;
else if (board->board_array[B6] == bP) black_score += PAWN_SHIELD_SCORE / 2;
if (board->board_array[C7] == bP) black_score += PAWN_SHIELD_SCORE;
else if (board->board_array[C6] == bP) black_score += PAWN_SHIELD_SCORE / 2;
}
return white_score - black_score;
}