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FabianoLothor/gchess.js

Last active April 1, 2018 01:06
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gchess.js
"use strict";
// Perf TODO:
// Merge material updating with psq values
// Put move scoring inline in generator
// Remove need for fliptable in psq tables. Access them by color
// Optimize pawn move generation
// Non-perf todo:
// Checks in first q?
// Pawn eval.
// Better king evaluation
// Better move sorting in PV nodes (especially root)
var g_debug = true;
var g_timeout = 40;
function GetFen(){
var result = "";
for (var row = 0; row < 8; row++) {
if (row != 0)
result += '/';
var empty = 0;
for (var col = 0; col < 8; col++) {
var piece = g_board[((row + 2) << 4) + col + 4];
if (piece == 0) {
empty++;
}
else {
if (empty != 0)
result += empty;
empty = 0;
var pieceChar = [" ", "p", "n", "b", "r", "q", "k", " "][(piece & 0x7)];
result += ((piece & colorWhite) != 0) ? pieceChar.toUpperCase() : pieceChar;
}
}
if (empty != 0) {
result += empty;
}
}
result += g_toMove == colorWhite ? " w" : " b";
result += " ";
if (g_castleRights == 0) {
result += "-";
}
else {
if ((g_castleRights & 1) != 0)
result += "K";
if ((g_castleRights & 2) != 0)
result += "Q";
if ((g_castleRights & 4) != 0)
result += "k";
if ((g_castleRights & 8) != 0)
result += "q";
}
result += " ";
if (g_enPassentSquare == -1) {
result += '-';
}
else {
result += FormatSquare(g_enPassentSquare);
}
return result;
}
function GetMoveSAN(move, validMoves) {
var from = move & 0xFF;
var to = (move >> 8) & 0xFF;
if (move & moveflagCastleKing) return "O-O";
if (move & moveflagCastleQueen) return "O-O-O";
var pieceType = g_board[from] & 0x7;
var result = ["", "", "N", "B", "R", "Q", "K", ""][pieceType];
var dupe = false, rowDiff = true, colDiff = true;
if (validMoves == null) {
validMoves = GenerateValidMoves();
}
for (var i = 0; i < validMoves.length; i++) {
var moveFrom = validMoves[i] & 0xFF;
var moveTo = (validMoves[i] >> 8) & 0xFF;
if (moveFrom != from &&
moveTo == to &&
(g_board[moveFrom] & 0x7) == pieceType) {
dupe = true;
if ((moveFrom & 0xF0) == (from & 0xF0)) {
rowDiff = false;
}
if ((moveFrom & 0x0F) == (from & 0x0F)) {
colDiff = false;
}
}
}
if (dupe) {
if (colDiff) {
result += FormatSquare(from).charAt(0);
} else if (rowDiff) {
result += FormatSquare(from).charAt(1);
} else {
result += FormatSquare(from);
}
} else if (pieceType == piecePawn && (g_board[to] != 0 || (move & moveflagEPC))) {
result += FormatSquare(from).charAt(0);
}
if (g_board[to] != 0 || (move & moveflagEPC)) {
result += "x";
}
result += FormatSquare(to);
if (move & moveflagPromotion) {
if (move & moveflagPromoteBishop) result += "=B";
else if (move & moveflagPromoteKnight) result += "=N";
else if (move & moveflagPromoteQueen) result += "=Q";
else result += "=R";
}
MakeMove(move);
if (g_inCheck) {
result += GenerateValidMoves().length == 0 ? "#" : "+";
}
UnmakeMove(move);
return result;
}
function FormatSquare(square) {
var letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
return letters[(square & 0xF) - 4] + ((9 - (square >> 4)) + 1);
}
function FormatMove(move) {
var result = FormatSquare(move & 0xFF) + FormatSquare((move >> 8) & 0xFF);
if (move & moveflagPromotion) {
if (move & moveflagPromoteBishop) result += "b";
else if (move & moveflagPromoteKnight) result += "n";
else if (move & moveflagPromoteQueen) result += "q";
else result += "r";
}
return result;
}
function GetMoveFromString(moveString) {
var moves = GenerateValidMoves();
for (var i = 0; i < moves.length; i++) {
if (FormatMove(moves[i]) == moveString) {
return moves[i];
}
}
alert("busted! ->" + moveString + " fen:" + GetFen());
}
function PVFromHash(move, ply) {
if (ply == 0)
return "";
if (move == 0) {
if (g_inCheck) return "checkmate";
return "stalemate";
}
var pvString = " " + GetMoveSAN(move);
MakeMove(move);
var hashNode = g_hashTable[g_hashKeyLow & g_hashMask];
if (hashNode != null && hashNode.lock == g_hashKeyHigh && hashNode.bestMove != null) {
pvString += PVFromHash(hashNode.bestMove, ply - 1);
}
UnmakeMove(move);
return pvString;
}
//
// Searching code
//
var g_startTime;
var g_nodeCount;
var g_qNodeCount;
var g_searchValid;
var g_globalPly = 0;
function Search(finishMoveCallback, maxPly, finishPlyCallback) {
var lastEval;
var alpha = minEval;
var beta = maxEval;
g_globalPly++;
g_nodeCount = 0;
g_qNodeCount = 0;
g_searchValid = true;
var bestMove = 0;
var value;
g_startTime = (new Date()).getTime();
var i;
for (i = 1; i <= maxPly && g_searchValid; i++) {
var tmp = AlphaBeta(i, 0, alpha, beta);
if (!g_searchValid) break;
value = tmp;
if (value > alpha && value < beta) {
alpha = value - 500;
beta = value + 500;
if (alpha < minEval) alpha = minEval;
if (beta > maxEval) beta = maxEval;
} else if (alpha != minEval) {
alpha = minEval;
beta = maxEval;
i--;
}
if (g_hashTable[g_hashKeyLow & g_hashMask] != null) {
bestMove = g_hashTable[g_hashKeyLow & g_hashMask].bestMove;
}
if (finishPlyCallback != null) {
finishPlyCallback(bestMove, value, (new Date()).getTime() - g_startTime, i);
}
}
if (finishMoveCallback != null) {
finishMoveCallback(bestMove, value, (new Date()).getTime() - g_startTime, i - 1);
}
}
var minEval = -2000000;
var maxEval = +2000000;
var minMateBuffer = minEval + 2000;
var maxMateBuffer = maxEval - 2000;
var materialTable = [0, 800, 3350, 3450, 5000, 9750, 600000];
var pawnAdj =
[
0, 0, 0, 0, 0, 0, 0, 0,
-25, 105, 135, 270, 270, 135, 105, -25,
-80, 0, 30, 176, 176, 30, 0, -80,
-85, -5, 25, 175, 175, 25, -5, -85,
-90, -10, 20, 125, 125, 20, -10, -90,
-95, -15, 15, 75, 75, 15, -15, -95,
-100, -20, 10, 70, 70, 10, -20, -100,
0, 0, 0, 0, 0, 0, 0, 0
];
var knightAdj =
[-200, -100, -50, -50, -50, -50, -100, -200,
-100, 0, 0, 0, 0, 0, 0, -100,
-50, 0, 60, 60, 60, 60, 0, -50,
-50, 0, 30, 60, 60, 30, 0, -50,
-50, 0, 30, 60, 60, 30, 0, -50,
-50, 0, 30, 30, 30, 30, 0, -50,
-100, 0, 0, 0, 0, 0, 0, -100,
-200, -50, -25, -25, -25, -25, -50, -200
];
var bishopAdj =
[ -50,-50,-25,-10,-10,-25,-50,-50,
-50,-25,-10, 0, 0,-10,-25,-50,
-25,-10, 0, 25, 25, 0,-10,-25,
-10, 0, 25, 40, 40, 25, 0,-10,
-10, 0, 25, 40, 40, 25, 0,-10,
-25,-10, 0, 25, 25, 0,-10,-25,
-50,-25,-10, 0, 0,-10,-25,-50,
-50,-50,-25,-10,-10,-25,-50,-50
];
var rookAdj =
[ -60, -30, -10, 20, 20, -10, -30, -60,
40, 70, 90,120,120, 90, 70, 40,
-60, -30, -10, 20, 20, -10, -30, -60,
-60, -30, -10, 20, 20, -10, -30, -60,
-60, -30, -10, 20, 20, -10, -30, -60,
-60, -30, -10, 20, 20, -10, -30, -60,
-60, -30, -10, 20, 20, -10, -30, -60,
-60, -30, -10, 20, 20, -10, -30, -60
];
var kingAdj =
[ 50, 150, -25, -125, -125, -25, 150, 50,
50, 150, -25, -125, -125, -25, 150, 50,
50, 150, -25, -125, -125, -25, 150, 50,
50, 150, -25, -125, -125, -25, 150, 50,
50, 150, -25, -125, -125, -25, 150, 50,
50, 150, -25, -125, -125, -25, 150, 50,
50, 150, -25, -125, -125, -25, 150, 50,
150, 250, 75, -25, -25, 75, 250, 150
];
var emptyAdj =
[0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
];
var pieceSquareAdj = new Array(8);
// Returns the square flipped
var flipTable = new Array(256);
function PawnEval(color) {
var pieceIdx = (color | 1) << 4;
var from = g_pieceList[pieceIdx++];
while (from != 0) {
from = g_pieceList[pieceIdx++];
}
}
function Mobility(color) {
var result = 0;
var from, to, mob, pieceIdx;
var enemy = color == 8 ? 0x10 : 0x8
var mobUnit = color == 8 ? g_mobUnit[0] : g_mobUnit[1];
// Knight mobility
mob = -3;
pieceIdx = (color | 2) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
mob += mobUnit[g_board[from + 31]];
mob += mobUnit[g_board[from + 33]];
mob += mobUnit[g_board[from + 14]];
mob += mobUnit[g_board[from - 14]];
mob += mobUnit[g_board[from - 31]];
mob += mobUnit[g_board[from - 33]];
mob += mobUnit[g_board[from + 18]];
mob += mobUnit[g_board[from - 18]];
from = g_pieceList[pieceIdx++];
}
result += 65 * mob;
// Bishop mobility
mob = -4;
pieceIdx = (color | 3) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from - 15; while (g_board[to] == 0) { to -= 15; mob++; }
if (g_board[to] & enemy) {
mob++;
if (!(g_board[to] & piecePawn)) {
to -= 15; while (g_board[to] == 0) to -= 15;
mob += mobUnit[g_board[to]] << 2;
}
}
to = from - 17; while (g_board[to] == 0) { to -= 17; mob++; }
if (g_board[to] & enemy) {
mob++;
if (!(g_board[to] & piecePawn)) {
to -= 17; while (g_board[to] == 0) to -= 17;
mob += mobUnit[g_board[to]] << 2;
}
}
to = from + 15; while (g_board[to] == 0) { to += 15; mob++; }
if (g_board[to] & enemy) {
mob++;
if (!(g_board[to] & piecePawn)) {
to += 15; while (g_board[to] == 0) to += 15;
mob += mobUnit[g_board[to]] << 2;
}
}
to = from + 17; while (g_board[to] == 0) { to += 17; mob++; }
if (g_board[to] & enemy) {
mob++;
if (!(g_board[to] & piecePawn)) {
to += 17; while (g_board[to] == 0) to += 17;
mob += mobUnit[g_board[to]] << 2;
}
}
from = g_pieceList[pieceIdx++];
}
result += 44 * mob;
// Rook mobility
mob = -4;
pieceIdx = (color | 4) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from - 1; while (g_board[to] == 0) { to--; mob++;} if (g_board[to] & enemy) mob++;
to = from + 1; while (g_board[to] == 0) { to++; mob++; } if (g_board[to] & enemy) mob++;
to = from + 16; while (g_board[to] == 0) { to += 16; mob++; } if (g_board[to] & enemy) mob++;
to = from - 16; while (g_board[to] == 0) { to -= 16; mob++; } if (g_board[to] & enemy) mob++;
from = g_pieceList[pieceIdx++];
}
result += 25 * mob;
// Queen mobility
mob = -2;
pieceIdx = (color | 5) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from - 15; while (g_board[to] == 0) { to -= 15; mob++; } if (g_board[to] & enemy) mob++;
to = from - 17; while (g_board[to] == 0) { to -= 17; mob++; } if (g_board[to] & enemy) mob++;
to = from + 15; while (g_board[to] == 0) { to += 15; mob++; } if (g_board[to] & enemy) mob++;
to = from + 17; while (g_board[to] == 0) { to += 17; mob++; } if (g_board[to] & enemy) mob++;
to = from - 1; while (g_board[to] == 0) { to--; mob++; } if (g_board[to] & enemy) mob++;
to = from + 1; while (g_board[to] == 0) { to++; mob++; } if (g_board[to] & enemy) mob++;
to = from + 16; while (g_board[to] == 0) { to += 16; mob++; } if (g_board[to] & enemy) mob++;
to = from - 16; while (g_board[to] == 0) { to -= 16; mob++; } if (g_board[to] & enemy) mob++;
from = g_pieceList[pieceIdx++];
}
result += 22 * mob;
return result;
}
function Evaluate() {
var curEval = g_baseEval;
var evalAdjust = 0;
// Black queen gone, then cancel white's penalty for king movement
if (g_pieceList[pieceQueen << 4] == 0)
evalAdjust -= pieceSquareAdj[pieceKing][g_pieceList[(colorWhite | pieceKing) << 4]];
// White queen gone, then cancel black's penalty for king movement
if (g_pieceList[(colorWhite | pieceQueen) << 4] == 0)
evalAdjust += pieceSquareAdj[pieceKing][flipTable[g_pieceList[pieceKing << 4]]];
// Black bishop pair
if (g_pieceCount[pieceBishop] >= 2)
evalAdjust -= 500;
// White bishop pair
if (g_pieceCount[pieceBishop | colorWhite] >= 2)
evalAdjust += 500;
var mobility = Mobility(8) - Mobility(0);
if (g_toMove == 0) {
// Black
curEval -= mobility;
curEval -= evalAdjust;
}
else {
curEval += mobility;
curEval += evalAdjust;
}
return curEval;
}
function ScoreMove(move){
var moveTo = (move >> 8) & 0xFF;
var captured = g_board[moveTo] & 0x7;
var piece = g_board[move & 0xFF];
var score;
if (captured != 0) {
var pieceType = piece & 0x7;
score = (captured << 5) - pieceType;
} else {
score = historyTable[piece & 0xF][moveTo];
}
return score;
}
function QSearch(alpha, beta, ply) {
g_qNodeCount++;
var realEval = g_inCheck ? (minEval + 1) : Evaluate();
if (realEval >= beta)
return realEval;
if (realEval > alpha)
alpha = realEval;
var moves = new Array();
var moveScores = new Array();
var wasInCheck = g_inCheck;
if (wasInCheck) {
// TODO: Fast check escape generator and fast checking moves generator
GenerateCaptureMoves(moves, null);
GenerateAllMoves(moves);
for (var i = 0; i < moves.length; i++) {
moveScores[i] = ScoreMove(moves[i]);
}
} else {
GenerateCaptureMoves(moves, null);
for (var i = 0; i < moves.length; i++) {
var captured = g_board[(moves[i] >> 8) & 0xFF] & 0x7;
var pieceType = g_board[moves[i] & 0xFF] & 0x7;
moveScores[i] = (captured << 5) - pieceType;
}
}
for (var i = 0; i < moves.length; i++) {
var bestMove = i;
for (var j = moves.length - 1; j > i; j--) {
if (moveScores[j] > moveScores[bestMove]) {
bestMove = j;
}
}
{
var tmpMove = moves[i];
moves[i] = moves[bestMove];
moves[bestMove] = tmpMove;
var tmpScore = moveScores[i];
moveScores[i] = moveScores[bestMove];
moveScores[bestMove] = tmpScore;
}
if (!wasInCheck && !See(moves[i])) {
continue;
}
if (!MakeMove(moves[i])) {
continue;
}
var value = -QSearch(-beta, -alpha, ply - 1);
UnmakeMove(moves[i]);
if (value > realEval) {
if (value >= beta)
return value;
if (value > alpha)
alpha = value;
realEval = value;
}
}
/* Disable checks... Too slow currently
if (ply == 0 && !wasInCheck) {
moves = new Array();
GenerateAllMoves(moves);
for (var i = 0; i < moves.length; i++) {
moveScores[i] = ScoreMove(moves[i]);
}
for (var i = 0; i < moves.length; i++) {
var bestMove = i;
for (var j = moves.length - 1; j > i; j--) {
if (moveScores[j] > moveScores[bestMove]) {
bestMove = j;
}
}
{
var tmpMove = moves[i];
moves[i] = moves[bestMove];
moves[bestMove] = tmpMove;
var tmpScore = moveScores[i];
moveScores[i] = moveScores[bestMove];
moveScores[bestMove] = tmpScore;
}
if (!MakeMove(moves[i])) {
continue;
}
var checking = g_inCheck;
UnmakeMove(moves[i]);
if (!checking) {
continue;
}
if (!See(moves[i])) {
continue;
}
MakeMove(moves[i]);
var value = -QSearch(-beta, -alpha, ply - 1);
UnmakeMove(moves[i]);
if (value > realEval) {
if (value >= beta)
return value;
if (value > alpha)
alpha = value;
realEval = value;
}
}
}
*/
return realEval;
}
function StoreHash(value, flags, ply, move, depth) {
if (value >= maxMateBuffer)
value += depth;
else if (value <= minMateBuffer)
value -= depth;
g_hashTable[g_hashKeyLow & g_hashMask] = new HashEntry(g_hashKeyHigh, value, flags, ply, move);
}
function IsHashMoveValid(hashMove) {
var from = hashMove & 0xFF;
var to = (hashMove >> 8) & 0xFF;
var ourPiece = g_board[from];
var pieceType = ourPiece & 0x7;
if (pieceType < piecePawn || pieceType > pieceKing) return false;
// Can't move a piece we don't control
if (g_toMove != (ourPiece & 0x8))
return false;
// Can't move to a square that has something of the same color
if (g_board[to] != 0 && (g_toMove == (g_board[to] & 0x8)))
return false;
if (pieceType == piecePawn) {
if (hashMove & moveflagEPC) {
return false;
}
// Valid moves are push, capture, double push, promotions
var dir = to - from;
if ((g_toMove == colorWhite) != (dir < 0)) {
// Pawns have to move in the right direction
return false;
}
var row = to & 0xF0;
if (((row == 0x90 && !g_toMove) ||
(row == 0x20 && g_toMove)) != (hashMove & moveflagPromotion)) {
// Handle promotions
return false;
}
if (dir == -16 || dir == 16) {
// White/Black push
return g_board[to] == 0;
} else if (dir == -15 || dir == -17 || dir == 15 || dir == 17) {
// White/Black capture
return g_board[to] != 0;
} else if (dir == -32) {
// Double white push
if (row != 0x60) return false;
if (g_board[to] != 0) return false;
if (g_board[from - 16] != 0) return false;
} else if (dir == 32) {
// Double black push
if (row != 0x50) return false;
if (g_board[to] != 0) return false;
if (g_board[from + 16] != 0) return false;
} else {
return false;
}
return true;
} else {
// This validates that this piece type can actually make the attack
if (hashMove >> 16) return false;
return IsSquareAttackableFrom(to, from);
}
}
function IsRepDraw() {
var stop = g_moveCount - 1 - g_move50;
stop = stop < 0 ? 0 : stop;
for (var i = g_moveCount - 5; i >= stop; i -= 2) {
if (g_repMoveStack[i] == g_hashKeyLow)
return true;
}
return false;
}
function MovePicker(hashMove, depth, killer1, killer2) {
this.hashMove = hashMove;
this.depth = depth;
this.killer1 = killer1;
this.killer2 = killer2;
this.moves = new Array();
this.losingCaptures = null;
this.moveCount = 0;
this.atMove = -1;
this.moveScores = null;
this.stage = 0;
this.nextMove = function () {
if (++this.atMove == this.moveCount) {
this.stage++;
if (this.stage == 1) {
if (this.hashMove != null && IsHashMoveValid(hashMove)) {
this.moves[0] = hashMove;
this.moveCount = 1;
}
if (this.moveCount != 1) {
this.hashMove = null;
this.stage++;
}
}
if (this.stage == 2) {
GenerateCaptureMoves(this.moves, null);
this.moveCount = this.moves.length;
this.moveScores = new Array(this.moveCount);
// Move ordering
for (var i = this.atMove; i < this.moveCount; i++) {
var captured = g_board[(this.moves[i] >> 8) & 0xFF] & 0x7;
var pieceType = g_board[this.moves[i] & 0xFF] & 0x7;
this.moveScores[i] = (captured << 5) - pieceType;
}
// No moves, onto next stage
if (this.atMove == this.moveCount) this.stage++;
}
if (this.stage == 3) {
if (IsHashMoveValid(this.killer1) &&
this.killer1 != this.hashMove) {
this.moves[this.moves.length] = this.killer1;
this.moveCount = this.moves.length;
} else {
this.killer1 = 0;
this.stage++;
}
}
if (this.stage == 4) {
if (IsHashMoveValid(this.killer2) &&
this.killer2 != this.hashMove) {
this.moves[this.moves.length] = this.killer2;
this.moveCount = this.moves.length;
} else {
this.killer2 = 0;
this.stage++;
}
}
if (this.stage == 5) {
GenerateAllMoves(this.moves);
this.moveCount = this.moves.length;
// Move ordering
for (var i = this.atMove; i < this.moveCount; i++) this.moveScores[i] = ScoreMove(this.moves[i]);
// No moves, onto next stage
if (this.atMove == this.moveCount) this.stage++;
}
if (this.stage == 6) {
// Losing captures
if (this.losingCaptures != null) {
for (var i = 0; i < this.losingCaptures.length; i++) {
this.moves[this.moves.length] = this.losingCaptures[i];
}
for (var i = this.atMove; i < this.moveCount; i++) this.moveScores[i] = ScoreMove(this.moves[i]);
this.moveCount = this.moves.length;
}
// No moves, onto next stage
if (this.atMove == this.moveCount) this.stage++;
}
if (this.stage == 7)
return 0;
}
var bestMove = this.atMove;
for (var j = this.atMove + 1; j < this.moveCount; j++) {
if (this.moveScores[j] > this.moveScores[bestMove]) {
bestMove = j;
}
}
if (bestMove != this.atMove) {
var tmpMove = this.moves[this.atMove];
this.moves[this.atMove] = this.moves[bestMove];
this.moves[bestMove] = tmpMove;
var tmpScore = this.moveScores[this.atMove];
this.moveScores[this.atMove] = this.moveScores[bestMove];
this.moveScores[bestMove] = tmpScore;
}
var candidateMove = this.moves[this.atMove];
if ((this.stage > 1 && candidateMove == this.hashMove) ||
(this.stage > 3 && candidateMove == this.killer1) ||
(this.stage > 4 && candidateMove == this.killer2)) {
return this.nextMove();
}
if (this.stage == 2 && !See(candidateMove)) {
if (this.losingCaptures == null) {
this.losingCaptures = new Array();
}
this.losingCaptures[this.losingCaptures.length] = candidateMove;
return this.nextMove();
}
return this.moves[this.atMove];
}
}
function AllCutNode(ply, depth, beta, allowNull) {
if (ply <= 0) {
return QSearch(beta - 1, beta, 0);
}
if ((g_nodeCount & 127) == 127) {
if ((new Date()).getTime() - g_startTime > g_timeout) {
// Time cutoff
g_searchValid = false;
return beta - 1;
}
}
g_nodeCount++;
if (IsRepDraw())
return 0;
// Mate distance pruning
if (minEval + depth >= beta)
return beta;
if (maxEval - (depth + 1) < beta)
return beta - 1;
var hashMove = null;
var hashNode = g_hashTable[g_hashKeyLow & g_hashMask];
if (hashNode != null && hashNode.lock == g_hashKeyHigh) {
hashMove = hashNode.bestMove;
if (hashNode.hashDepth >= ply) {
var hashValue = hashNode.value;
// Fixup mate scores
if (hashValue >= maxMateBuffer)
hashValue -= depth;
else if (hashValue <= minMateBuffer)
hashValue += depth;
if (hashNode.flags == hashflagExact)
return hashValue;
if (hashNode.flags == hashflagAlpha && hashValue < beta)
return hashValue;
if (hashNode.flags == hashflagBeta && hashValue >= beta)
return hashValue;
}
}
// TODO - positional gain?
if (!g_inCheck &&
allowNull &&
beta > minMateBuffer &&
beta < maxMateBuffer) {
// Try some razoring
if (hashMove == null &&
ply < 4) {
var razorMargin = 2500 + 200 * ply;
if (g_baseEval < beta - razorMargin) {
var razorBeta = beta - razorMargin;
var v = QSearch(razorBeta - 1, razorBeta, 0);
if (v < razorBeta)
return v;
}
}
// TODO - static null move
// Null move
if (ply > 1 &&
g_baseEval >= beta - (ply >= 4 ? 2500 : 0) &&
// Disable null move if potential zugzwang (no big pieces)
(g_pieceCount[pieceBishop | g_toMove] != 0 ||
g_pieceCount[pieceKnight | g_toMove] != 0 ||
g_pieceCount[pieceRook | g_toMove] != 0 ||
g_pieceCount[pieceQueen | g_toMove] != 0)) {
var r = 3 + (ply >= 5 ? 1 : ply / 4);
if (g_baseEval - beta > 1500) r++;
g_toMove = 8 - g_toMove;
g_baseEval = -g_baseEval;
g_hashKeyLow ^= g_zobristBlackLow;
g_hashKeyHigh ^= g_zobristBlackHigh;
var value = -AllCutNode(ply - r, depth + 1, -(beta - 1), false);
g_hashKeyLow ^= g_zobristBlackLow;
g_hashKeyHigh ^= g_zobristBlackHigh;
g_toMove = 8 - g_toMove;
g_baseEval = -g_baseEval;
if (value >= beta)
return beta;
}
}
var moveMade = false;
var realEval = minEval - 1;
var inCheck = g_inCheck;
var movePicker = new MovePicker(hashMove, depth, g_killers[depth][0], g_killers[depth][1]);
for (;;) {
var currentMove = movePicker.nextMove();
if (currentMove == 0) {
break;
}
var plyToSearch = ply - 1;
if (!MakeMove(currentMove)) {
continue;
}
var value;
var doFullSearch = true;
if (g_inCheck) {
// Check extensions
plyToSearch++;
} else {
var reduced = plyToSearch - (movePicker.atMove > 14 ? 2 : 1);
// Futility pruning
/* if (movePicker.stage == 5 && !inCheck) {
if (movePicker.atMove >= (15 + (1 << (5 * ply) >> 2)) &&
realEval > minMateBuffer) {
UnmakeMove(currentMove);
continue;
}
if (ply < 7) {
var reducedPly = reduced <= 0 ? 0 : reduced;
var futilityValue = -g_baseEval + (900 * (reducedPly + 2)) - (movePicker.atMove * 10);
if (futilityValue < beta) {
if (futilityValue > realEval) {
realEval = futilityValue;
}
UnmakeMove(currentMove);
continue;
}
}
}*/
// Late move reductions
if (movePicker.stage == 5 && movePicker.atMove > 5 && ply >= 3) {
value = -AllCutNode(reduced, depth + 1, -(beta - 1), true);
doFullSearch = (value >= beta);
}
}
if (doFullSearch) {
value = -AllCutNode(plyToSearch, depth + 1, -(beta - 1), true);
}
moveMade = true;
UnmakeMove(currentMove);
if (!g_searchValid) {
return beta - 1;
}
if (value > realEval) {
if (value >= beta) {
var histTo = (currentMove >> 8) & 0xFF;
if (g_board[histTo] == 0) {
var histPiece = g_board[currentMove & 0xFF] & 0xF;
historyTable[histPiece][histTo] += ply * ply;
if (historyTable[histPiece][histTo] > 32767) {
historyTable[histPiece][histTo] >>= 1;
}
if (g_killers[depth][0] != currentMove) {
g_killers[depth][1] = g_killers[depth][0];
g_killers[depth][0] = currentMove;
}
}
StoreHash(value, hashflagBeta, ply, currentMove, depth);
return value;
}
realEval = value;
hashMove = currentMove;
}
}
if (!moveMade) {
// If we have no valid moves it's either stalemate or checkmate
if (g_inCheck)
// Checkmate.
return minEval + depth;
else
// Stalemate
return 0;
}
StoreHash(realEval, hashflagAlpha, ply, hashMove, depth);
return realEval;
}
function AlphaBeta(ply, depth, alpha, beta) {
if (ply <= 0) {
return QSearch(alpha, beta, 0);
}
g_nodeCount++;
if (depth > 0 && IsRepDraw())
return 0;
// Mate distance pruning
var oldAlpha = alpha;
alpha = alpha < minEval + depth ? alpha : minEval + depth;
beta = beta > maxEval - (depth + 1) ? beta : maxEval - (depth + 1);
if (alpha >= beta)
return alpha;
var hashMove = null;
var hashFlag = hashflagAlpha;
var hashNode = g_hashTable[g_hashKeyLow & g_hashMask];
if (hashNode != null && hashNode.lock == g_hashKeyHigh) {
hashMove = hashNode.bestMove;
}
var inCheck = g_inCheck;
var moveMade = false;
var realEval = minEval;
var movePicker = new MovePicker(hashMove, depth, g_killers[depth][0], g_killers[depth][1]);
for (;;) {
var currentMove = movePicker.nextMove();
if (currentMove == 0) {
break;
}
var plyToSearch = ply - 1;
if (!MakeMove(currentMove)) {
continue;
}
if (g_inCheck) {
// Check extensions
plyToSearch++;
}
var value;
if (moveMade) {
value = -AllCutNode(plyToSearch, depth + 1, -alpha, true);
if (value > alpha) {
value = -AlphaBeta(plyToSearch, depth + 1, -beta, -alpha);
}
} else {
value = -AlphaBeta(plyToSearch, depth + 1, -beta, -alpha);
}
moveMade = true;
UnmakeMove(currentMove);
if (!g_searchValid) {
return alpha;
}
if (value > realEval) {
if (value >= beta) {
var histTo = (currentMove >> 8) & 0xFF;
if (g_board[histTo] == 0) {
var histPiece = g_board[currentMove & 0xFF] & 0xF;
historyTable[histPiece][histTo] += ply * ply;
if (historyTable[histPiece][histTo] > 32767) {
historyTable[histPiece][histTo] >>= 1;
}
if (g_killers[depth][0] != currentMove) {
g_killers[depth][1] = g_killers[depth][0];
g_killers[depth][0] = currentMove;
}
}
StoreHash(value, hashflagBeta, ply, currentMove, depth);
return value;
}
if (value > oldAlpha) {
hashFlag = hashflagExact;
alpha = value;
}
realEval = value;
hashMove = currentMove;
}
}
if (!moveMade) {
// If we have no valid moves it's either stalemate or checkmate
if (inCheck)
// Checkmate.
return minEval + depth;
else
// Stalemate
return 0;
}
StoreHash(realEval, hashFlag, ply, hashMove, depth);
return realEval;
}
//
// Board code
//
// This somewhat funky scheme means that a piece is indexed by it's lower 4 bits when accessing in arrays. The fifth bit (black bit)
// is used to allow quick edge testing on the board.
var colorBlack = 0x10;
var colorWhite = 0x08;
var pieceEmpty = 0x00;
var piecePawn = 0x01;
var pieceKnight = 0x02;
var pieceBishop = 0x03;
var pieceRook = 0x04;
var pieceQueen = 0x05;
var pieceKing = 0x06;
var g_vectorDelta = new Array(256);
var g_bishopDeltas = [-15, -17, 15, 17];
var g_knightDeltas = [31, 33, 14, -14, -31, -33, 18, -18];
var g_rookDeltas = [-1, +1, -16, +16];
var g_queenDeltas = [-1, +1, -15, +15, -17, +17, -16, +16];
var g_castleRightsMask = [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 7,15,15,15, 3,15,15,11, 0, 0, 0, 0,
0, 0, 0, 0,15,15,15,15,15,15,15,15, 0, 0, 0, 0,
0, 0, 0, 0,15,15,15,15,15,15,15,15, 0, 0, 0, 0,
0, 0, 0, 0,15,15,15,15,15,15,15,15, 0, 0, 0, 0,
0, 0, 0, 0,15,15,15,15,15,15,15,15, 0, 0, 0, 0,
0, 0, 0, 0,15,15,15,15,15,15,15,15, 0, 0, 0, 0,
0, 0, 0, 0,15,15,15,15,15,15,15,15, 0, 0, 0, 0,
0, 0, 0, 0,13,15,15,15,12,15,15,14, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
var moveflagEPC = 0x2 << 16;
var moveflagCastleKing = 0x4 << 16;
var moveflagCastleQueen = 0x8 << 16;
var moveflagPromotion = 0x10 << 16;
var moveflagPromoteKnight = 0x20 << 16;
var moveflagPromoteQueen = 0x40 << 16;
var moveflagPromoteBishop = 0x80 << 16;
function MT() {
var N = 624;
var M = 397;
var MAG01 = [0x0, 0x9908b0df];
this.mt = new Array(N);
this.mti = N + 1;
this.setSeed = function()
{
var a = arguments;
switch (a.length) {
case 1:
if (a[0].constructor === Number) {
this.mt[0]= a[0];
for (var i = 1; i < N; ++i) {
var s = this.mt[i - 1] ^ (this.mt[i - 1] >>> 30);
this.mt[i] = ((1812433253 * ((s & 0xffff0000) >>> 16))
<< 16)
+ 1812433253 * (s & 0x0000ffff)
+ i;
}
this.mti = N;
return;
}
this.setSeed(19650218);
var l = a[0].length;
var i = 1;
var j = 0;
for (var k = N > l ? N : l; k != 0; --k) {
var s = this.mt[i - 1] ^ (this.mt[i - 1] >>> 30)
this.mt[i] = (this.mt[i]
^ (((1664525 * ((s & 0xffff0000) >>> 16)) << 16)
+ 1664525 * (s & 0x0000ffff)))
+ a[0][j]
+ j;
if (++i >= N) {
this.mt[0] = this.mt[N - 1];
i = 1;
}
if (++j >= l) {
j = 0;
}
}
for (var k = N - 1; k != 0; --k) {
var s = this.mt[i - 1] ^ (this.mt[i - 1] >>> 30);
this.mt[i] = (this.mt[i]
^ (((1566083941 * ((s & 0xffff0000) >>> 16)) << 16)
+ 1566083941 * (s & 0x0000ffff)))
- i;
if (++i >= N) {
this.mt[0] = this.mt[N-1];
i = 1;
}
}
this.mt[0] = 0x80000000;
return;
default:
var seeds = new Array();
for (var i = 0; i < a.length; ++i) {
seeds.push(a[i]);
}
this.setSeed(seeds);
return;
}
}
this.setSeed(0x1BADF00D);
this.next = function (bits)
{
if (this.mti >= N) {
var x = 0;
for (var k = 0; k < N - M; ++k) {
x = (this.mt[k] & 0x80000000) | (this.mt[k + 1] & 0x7fffffff);
this.mt[k] = this.mt[k + M] ^ (x >>> 1) ^ MAG01[x & 0x1];
}
for (var k = N - M; k < N - 1; ++k) {
x = (this.mt[k] & 0x80000000) | (this.mt[k + 1] & 0x7fffffff);
this.mt[k] = this.mt[k + (M - N)] ^ (x >>> 1) ^ MAG01[x & 0x1];
}
x = (this.mt[N - 1] & 0x80000000) | (this.mt[0] & 0x7fffffff);
this.mt[N - 1] = this.mt[M - 1] ^ (x >>> 1) ^ MAG01[x & 0x1];
this.mti = 0;
}
var y = this.mt[this.mti++];
y ^= y >>> 11;
y ^= (y << 7) & 0x9d2c5680;
y ^= (y << 15) & 0xefc60000;
y ^= y >>> 18;
return (y >>> (32 - bits)) & 0xFFFFFFFF;
}
}
// Position variables
var g_board = new Array(256); // Sentinel 0x80, pieces are in low 4 bits, 0x8 for color, 0x7 bits for piece type
var g_toMove; // side to move, 0 or 8, 0 = black, 8 = white
var g_castleRights; // bitmask representing castling rights, 1 = wk, 2 = wq, 4 = bk, 8 = bq
var g_enPassentSquare;
var g_baseEval;
var g_hashKeyLow, g_hashKeyHigh;
var g_inCheck;
// Utility variables
var g_moveCount = 0;
var g_moveUndoStack = new Array();
var g_move50 = 0;
var g_repMoveStack = new Array();
var g_hashSize = 1 << 22;
var g_hashMask = g_hashSize - 1;
var g_hashTable;
var g_killers;
var historyTable = new Array(32);
var g_zobristLow;
var g_zobristHigh;
var g_zobristBlackLow;
var g_zobristBlackHigh;
// Evaulation variables
var g_mobUnit;
var hashflagAlpha = 1;
var hashflagBeta = 2;
var hashflagExact = 3;
function HashEntry(lock, value, flags, hashDepth, bestMove, globalPly) {
this.lock = lock;
this.value = value;
this.flags = flags;
this.hashDepth = hashDepth;
this.bestMove = bestMove;
}
function MakeSquare(row, column) {
return ((row + 2) << 4) | (column + 4);
}
function MakeTable(table) {
var result = new Array(256);
for (var i = 0; i < 256; i++) {
result[i] = 0;
}
for (var row = 0; row < 8; row++) {
for (var col = 0; col < 8; col++) {
result[MakeSquare(row, col)] = table[row * 8 + col];
}
}
return result;
}
function ResetGame() {
g_killers = new Array(128);
for (var i = 0; i < 128; i++) {
g_killers[i] = [0, 0];
}
g_hashTable = new Array(g_hashSize);
for (var i = 0; i < 32; i++) {
historyTable[i] = new Array(256);
for (var j = 0; j < 256; j++)
historyTable[i][j] = 0;
}
var mt = new MT(0x1badf00d);
g_zobristLow = new Array(256);
g_zobristHigh = new Array(256);
for (var i = 0; i < 256; i++) {
g_zobristLow[i] = new Array(16);
g_zobristHigh[i] = new Array(16);
for (var j = 0; j < 16; j++) {
g_zobristLow[i][j] = mt.next(32);
g_zobristHigh[i][j] = mt.next(32);
}
}
g_zobristBlackLow = mt.next(32);
g_zobristBlackHigh = mt.next(32);
for (var row = 0; row < 8; row++) {
for (var col = 0; col < 8; col++) {
var square = MakeSquare(row, col);
flipTable[square] = MakeSquare(7 - row, col);
}
}
pieceSquareAdj[piecePawn] = MakeTable(pawnAdj);
pieceSquareAdj[pieceKnight] = MakeTable(knightAdj);
pieceSquareAdj[pieceBishop] = MakeTable(bishopAdj);
pieceSquareAdj[pieceRook] = MakeTable(rookAdj);
pieceSquareAdj[pieceQueen] = MakeTable(emptyAdj);
pieceSquareAdj[pieceKing] = MakeTable(kingAdj);
var pieceDeltas = [[], [], g_knightDeltas, g_bishopDeltas, g_rookDeltas, g_queenDeltas, g_queenDeltas];
for (var i = 0; i < 256; i++) {
g_vectorDelta[i] = new Object();
g_vectorDelta[i].delta = 0;
g_vectorDelta[i].pieceMask = new Array(2);
g_vectorDelta[i].pieceMask[0] = 0;
g_vectorDelta[i].pieceMask[1] = 0;
}
// Initialize the vector delta table
for (var row = 0; row < 0x80; row += 0x10)
for (var col = 0; col < 0x8; col++) {
var square = row | col;
// Pawn moves
var index = square - (square - 17) + 128;
g_vectorDelta[index].pieceMask[colorWhite >> 3] |= (1 << piecePawn);
index = square - (square - 15) + 128;
g_vectorDelta[index].pieceMask[colorWhite >> 3] |= (1 << piecePawn);
index = square - (square + 17) + 128;
g_vectorDelta[index].pieceMask[0] |= (1 << piecePawn);
index = square - (square + 15) + 128;
g_vectorDelta[index].pieceMask[0] |= (1 << piecePawn);
for (var i = pieceKnight; i <= pieceKing; i++) {
for (var dir = 0; dir < pieceDeltas[i].length; dir++) {
var target = square + pieceDeltas[i][dir];
while (!(target & 0x88)) {
index = square - target + 128;
g_vectorDelta[index].pieceMask[colorWhite >> 3] |= (1 << i);
g_vectorDelta[index].pieceMask[0] |= (1 << i);
var flip = -1;
if (square < target)
flip = 1;
if ((square & 0xF0) == (target & 0xF0)) {
// On the same row
g_vectorDelta[index].delta = flip * 1;
} else if ((square & 0x0F) == (target & 0x0F)) {
// On the same column
g_vectorDelta[index].delta = flip * 16;
} else if ((square % 15) == (target % 15)) {
g_vectorDelta[index].delta = flip * 15;
} else if ((square % 17) == (target % 17)) {
g_vectorDelta[index].delta = flip * 17;
}
if (i == pieceKnight) {
g_vectorDelta[index].delta = pieceDeltas[i][dir];
break;
}
if (i == pieceKing)
break;
target += pieceDeltas[i][dir];
}
}
}
}
InitializeEval();
InitializeFromFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1");
}
function InitializeEval() {
g_mobUnit = new Array(2);
for (var i = 0; i < 2; i++) {
g_mobUnit[i] = new Array();
var enemy = i == 0 ? 0x10 : 8;
var friend = i == 0 ? 8 : 0x10;
g_mobUnit[i][0] = 1;
g_mobUnit[i][0x80] = 0;
g_mobUnit[i][enemy | piecePawn] = 1;
g_mobUnit[i][enemy | pieceBishop] = 2;
g_mobUnit[i][enemy | pieceKnight] = 2;
g_mobUnit[i][enemy | pieceRook] = 4;
g_mobUnit[i][enemy | pieceQueen] = 6;
g_mobUnit[i][enemy | pieceKing] = 6;
g_mobUnit[i][friend | piecePawn] = 0;
g_mobUnit[i][friend | pieceBishop] = 0;
g_mobUnit[i][friend | pieceKnight] = 0;
g_mobUnit[i][friend | pieceRook] = 0;
g_mobUnit[i][friend | pieceQueen] = 0;
g_mobUnit[i][friend | pieceKing] = 0;
}
}
function SetHash() {
var result = new Object();
result.hashKeyLow = 0;
result.hashKeyHigh = 0;
for (var i = 0; i < 256; i++) {
var piece = g_board[i];
if (piece & 0x18) {
result.hashKeyLow ^= g_zobristLow[i][piece & 0xF]
result.hashKeyHigh ^= g_zobristHigh[i][piece & 0xF]
}
}
if (!g_toMove) {
result.hashKeyLow ^= g_zobristBlackLow;
result.hashKeyHigh ^= g_zobristBlackHigh;
}
return result;
}
function InitializeFromFen(fen) {
var chunks = fen.split(' ');
for (var i = 0; i < 256; i++)
g_board[i] = 0x80;
var row = 0;
var col = 0;
var pieces = chunks[0];
for (var i = 0; i < pieces.length; i++) {
var c = pieces.charAt(i);
if (c == '/') {
row++;
col = 0;
}
else {
if (c >= '0' && c <= '9') {
for (var j = 0; j < parseInt(c); j++) {
g_board[MakeSquare(row, col)] = 0;
col++;
}
}
else {
var isBlack = c >= 'a' && c <= 'z';
var piece = isBlack ? colorBlack : colorWhite;
if (!isBlack)
c = pieces.toLowerCase().charAt(i);
switch (c) {
case 'p':
piece |= piecePawn;
break;
case 'b':
piece |= pieceBishop;
break;
case 'n':
piece |= pieceKnight;
break;
case 'r':
piece |= pieceRook;
break;
case 'q':
piece |= pieceQueen;
break;
case 'k':
piece |= pieceKing;
break;
}
g_board[MakeSquare(row, col)] = piece;
col++;
}
}
}
InitializePieceList();
g_toMove = chunks[1].charAt(0) == 'w' ? colorWhite : 0;
var them = 8 - g_toMove;
g_castleRights = 0;
if (chunks[2].indexOf('K') != -1) {
if (g_board[MakeSquare(7, 4)] != (pieceKing | colorWhite) ||
g_board[MakeSquare(7, 7)] != (pieceRook | colorWhite)) {
return 'Invalid FEN: White kingside castling not allowed';
}
g_castleRights |= 1;
}
if (chunks[2].indexOf('Q') != -1) {
if (g_board[MakeSquare(7, 4)] != (pieceKing | colorWhite) ||
g_board[MakeSquare(7, 0)] != (pieceRook | colorWhite)) {
return 'Invalid FEN: White queenside castling not allowed';
}
g_castleRights |= 2;
}
if (chunks[2].indexOf('k') != -1) {
if (g_board[MakeSquare(0, 4)] != (pieceKing | colorBlack) ||
g_board[MakeSquare(0, 7)] != (pieceRook | colorBlack)) {
return 'Invalid FEN: Black kingside castling not allowed';
}
g_castleRights |= 4;
}
if (chunks[2].indexOf('q') != -1) {
if (g_board[MakeSquare(0, 4)] != (pieceKing | colorBlack) ||
g_board[MakeSquare(0, 0)] != (pieceRook | colorBlack)) {
return 'Invalid FEN: Black queenside castling not allowed';
}
g_castleRights |= 8;
}
g_enPassentSquare = -1;
if (chunks[3].indexOf('-') == -1) {
var col = chunks[3].charAt(0).charCodeAt() - 'a'.charCodeAt();
var row = 8 - (chunks[3].charAt(1).charCodeAt() - '0'.charCodeAt());
g_enPassentSquare = MakeSquare(row, col);
}
var hashResult = SetHash();
g_hashKeyLow = hashResult.hashKeyLow;
g_hashKeyHigh = hashResult.hashKeyHigh;
g_baseEval = 0;
for (var i = 0; i < 256; i++) {
if (g_board[i] & colorWhite) {
g_baseEval += pieceSquareAdj[g_board[i] & 0x7][i];
g_baseEval += materialTable[g_board[i] & 0x7];
} else if (g_board[i] & colorBlack) {
g_baseEval -= pieceSquareAdj[g_board[i] & 0x7][flipTable[i]];
g_baseEval -= materialTable[g_board[i] & 0x7];
}
}
if (!g_toMove) g_baseEval = -g_baseEval;
g_move50 = 0;
g_inCheck = IsSquareAttackable(g_pieceList[(g_toMove | pieceKing) << 4], them);
// Check for king capture (invalid FEN)
if (IsSquareAttackable(g_pieceList[(them | pieceKing) << 4], g_toMove)) {
return 'Invalid FEN: Can capture king';
}
// Checkmate/stalemate
if (GenerateValidMoves().length == 0) {
return g_inCheck ? 'Checkmate' : 'Stalemate';
}
return '';
}
var g_pieceIndex = new Array(256);
var g_pieceList = new Array(2 * 8 * 16);
var g_pieceCount = new Array(2 * 8);
function InitializePieceList() {
for (var i = 0; i < 16; i++) {
g_pieceCount[i] = 0;
for (var j = 0; j < 16; j++) {
// 0 is used as the terminator for piece lists
g_pieceList[(i << 4) | j] = 0;
}
}
for (var i = 0; i < 256; i++) {
g_pieceIndex[i] = 0;
if (g_board[i] & (colorWhite | colorBlack)) {
var piece = g_board[i] & 0xF;
g_pieceList[(piece << 4) | g_pieceCount[piece]] = i;
g_pieceIndex[i] = g_pieceCount[piece];
g_pieceCount[piece]++;
}
}
}
function MakeMove(move){
var me = g_toMove >> 3;
var otherColor = 8 - g_toMove;
var flags = move & 0xFF0000;
var to = (move >> 8) & 0xFF;
var from = move & 0xFF;
var captured = g_board[to];
var piece = g_board[from];
var epcEnd = to;
if (flags & moveflagEPC) {
epcEnd = me ? (to + 0x10) : (to - 0x10);
captured = g_board[epcEnd];
g_board[epcEnd] = pieceEmpty;
}
g_moveUndoStack[g_moveCount] = new UndoHistory(g_enPassentSquare, g_castleRights, g_inCheck, g_baseEval, g_hashKeyLow, g_hashKeyHigh, g_move50, captured);
g_moveCount++;
g_enPassentSquare = -1;
if (flags) {
if (flags & moveflagCastleKing) {
if (IsSquareAttackable(from + 1, otherColor) ||
IsSquareAttackable(from + 2, otherColor)) {
g_moveCount--;
return false;
}
var rook = g_board[to + 1];
g_hashKeyLow ^= g_zobristLow[to + 1][rook & 0xF];
g_hashKeyHigh ^= g_zobristHigh[to + 1][rook & 0xF];
g_hashKeyLow ^= g_zobristLow[to - 1][rook & 0xF];
g_hashKeyHigh ^= g_zobristHigh[to - 1][rook & 0xF];
g_board[to - 1] = rook;
g_board[to + 1] = pieceEmpty;
g_baseEval -= pieceSquareAdj[rook & 0x7][me == 0 ? flipTable[to + 1] : (to + 1)];
g_baseEval += pieceSquareAdj[rook & 0x7][me == 0 ? flipTable[to - 1] : (to - 1)];
var rookIndex = g_pieceIndex[to + 1];
g_pieceIndex[to - 1] = rookIndex;
g_pieceList[((rook & 0xF) << 4) | rookIndex] = to - 1;
} else if (flags & moveflagCastleQueen) {
if (IsSquareAttackable(from - 1, otherColor) ||
IsSquareAttackable(from - 2, otherColor)) {
g_moveCount--;
return false;
}
var rook = g_board[to - 2];
g_hashKeyLow ^= g_zobristLow[to -2][rook & 0xF];
g_hashKeyHigh ^= g_zobristHigh[to - 2][rook & 0xF];
g_hashKeyLow ^= g_zobristLow[to + 1][rook & 0xF];
g_hashKeyHigh ^= g_zobristHigh[to + 1][rook & 0xF];
g_board[to + 1] = rook;
g_board[to - 2] = pieceEmpty;
g_baseEval -= pieceSquareAdj[rook & 0x7][me == 0 ? flipTable[to - 2] : (to - 2)];
g_baseEval += pieceSquareAdj[rook & 0x7][me == 0 ? flipTable[to + 1] : (to + 1)];
var rookIndex = g_pieceIndex[to - 2];
g_pieceIndex[to + 1] = rookIndex;
g_pieceList[((rook & 0xF) << 4) | rookIndex] = to + 1;
}
}
if (captured) {
// Remove our piece from the piece list
var capturedType = captured & 0xF;
g_pieceCount[capturedType]--;
var lastPieceSquare = g_pieceList[(capturedType << 4) | g_pieceCount[capturedType]];
g_pieceIndex[lastPieceSquare] = g_pieceIndex[epcEnd];
g_pieceList[(capturedType << 4) | g_pieceIndex[lastPieceSquare]] = lastPieceSquare;
g_pieceList[(capturedType << 4) | g_pieceCount[capturedType]] = 0;
g_baseEval += materialTable[captured & 0x7];
g_baseEval += pieceSquareAdj[captured & 0x7][me ? flipTable[epcEnd] : epcEnd];
g_hashKeyLow ^= g_zobristLow[epcEnd][capturedType];
g_hashKeyHigh ^= g_zobristHigh[epcEnd][capturedType];
g_move50 = 0;
} else if ((piece & 0x7) == piecePawn) {
var diff = to - from;
if (diff < 0) diff = -diff;
if (diff > 16) {
g_enPassentSquare = me ? (to + 0x10) : (to - 0x10);
}
g_move50 = 0;
}
g_hashKeyLow ^= g_zobristLow[from][piece & 0xF];
g_hashKeyHigh ^= g_zobristHigh[from][piece & 0xF];
g_hashKeyLow ^= g_zobristLow[to][piece & 0xF];
g_hashKeyHigh ^= g_zobristHigh[to][piece & 0xF];
g_hashKeyLow ^= g_zobristBlackLow;
g_hashKeyHigh ^= g_zobristBlackHigh;
g_castleRights &= g_castleRightsMask[from] & g_castleRightsMask[to];
g_baseEval -= pieceSquareAdj[piece & 0x7][me == 0 ? flipTable[from] : from];
// Move our piece in the piece list
g_pieceIndex[to] = g_pieceIndex[from];
g_pieceList[((piece & 0xF) << 4) | g_pieceIndex[to]] = to;
if (flags & moveflagPromotion) {
var newPiece = piece & (~0x7);
if (flags & moveflagPromoteKnight)
newPiece |= pieceKnight;
else if (flags & moveflagPromoteQueen)
newPiece |= pieceQueen;
else if (flags & moveflagPromoteBishop)
newPiece |= pieceBishop;
else
newPiece |= pieceRook;
g_hashKeyLow ^= g_zobristLow[to][piece & 0xF];
g_hashKeyHigh ^= g_zobristHigh[to][piece & 0xF];
g_board[to] = newPiece;
g_hashKeyLow ^= g_zobristLow[to][newPiece & 0xF];
g_hashKeyHigh ^= g_zobristHigh[to][newPiece & 0xF];
g_baseEval += pieceSquareAdj[newPiece & 0x7][me == 0 ? flipTable[to] : to];
g_baseEval -= materialTable[piecePawn];
g_baseEval += materialTable[newPiece & 0x7];
var pawnType = piece & 0xF;
var promoteType = newPiece & 0xF;
g_pieceCount[pawnType]--;
var lastPawnSquare = g_pieceList[(pawnType << 4) | g_pieceCount[pawnType]];
g_pieceIndex[lastPawnSquare] = g_pieceIndex[to];
g_pieceList[(pawnType << 4) | g_pieceIndex[lastPawnSquare]] = lastPawnSquare;
g_pieceList[(pawnType << 4) | g_pieceCount[pawnType]] = 0;
g_pieceIndex[to] = g_pieceCount[promoteType];
g_pieceList[(promoteType << 4) | g_pieceIndex[to]] = to;
g_pieceCount[promoteType]++;
} else {
g_board[to] = g_board[from];
g_baseEval += pieceSquareAdj[piece & 0x7][me == 0 ? flipTable[to] : to];
}
g_board[from] = pieceEmpty;
g_toMove = otherColor;
g_baseEval = -g_baseEval;
if ((piece & 0x7) == pieceKing || g_inCheck) {
if (IsSquareAttackable(g_pieceList[(pieceKing | (8 - g_toMove)) << 4], otherColor)) {
UnmakeMove(move);
return false;
}
} else {
var kingPos = g_pieceList[(pieceKing | (8 - g_toMove)) << 4];
if (ExposesCheck(from, kingPos)) {
UnmakeMove(move);
return false;
}
if (epcEnd != to) {
if (ExposesCheck(epcEnd, kingPos)) {
UnmakeMove(move);
return false;
}
}
}
g_inCheck = false;
if (flags <= moveflagEPC) {
var theirKingPos = g_pieceList[(pieceKing | g_toMove) << 4];
// First check if the piece we moved can attack the enemy king
g_inCheck = IsSquareAttackableFrom(theirKingPos, to);
if (!g_inCheck) {
// Now check if the square we moved from exposes check on the enemy king
g_inCheck = ExposesCheck(from, theirKingPos);
if (!g_inCheck) {
// Finally, ep. capture can cause another square to be exposed
if (epcEnd != to) {
g_inCheck = ExposesCheck(epcEnd, theirKingPos);
}
}
}
}
else {
// Castle or promotion, slow check
g_inCheck = IsSquareAttackable(g_pieceList[(pieceKing | g_toMove) << 4], 8 - g_toMove);
}
g_repMoveStack[g_moveCount - 1] = g_hashKeyLow;
g_move50++;
return true;
}
function UnmakeMove(move){
g_toMove = 8 - g_toMove;
g_baseEval = -g_baseEval;
g_moveCount--;
g_enPassentSquare = g_moveUndoStack[g_moveCount].ep;
g_castleRights = g_moveUndoStack[g_moveCount].castleRights;
g_inCheck = g_moveUndoStack[g_moveCount].inCheck;
g_baseEval = g_moveUndoStack[g_moveCount].baseEval;
g_hashKeyLow = g_moveUndoStack[g_moveCount].hashKeyLow;
g_hashKeyHigh = g_moveUndoStack[g_moveCount].hashKeyHigh;
g_move50 = g_moveUndoStack[g_moveCount].move50;
var otherColor = 8 - g_toMove;
var me = g_toMove >> 3;
var them = otherColor >> 3;
var flags = move & 0xFF0000;
var captured = g_moveUndoStack[g_moveCount].captured;
var to = (move >> 8) & 0xFF;
var from = move & 0xFF;
var piece = g_board[to];
if (flags) {
if (flags & moveflagCastleKing) {
var rook = g_board[to - 1];
g_board[to + 1] = rook;
g_board[to - 1] = pieceEmpty;
var rookIndex = g_pieceIndex[to - 1];
g_pieceIndex[to + 1] = rookIndex;
g_pieceList[((rook & 0xF) << 4) | rookIndex] = to + 1;
}
else if (flags & moveflagCastleQueen) {
var rook = g_board[to + 1];
g_board[to - 2] = rook;
g_board[to + 1] = pieceEmpty;
var rookIndex = g_pieceIndex[to + 1];
g_pieceIndex[to - 2] = rookIndex;
g_pieceList[((rook & 0xF) << 4) | rookIndex] = to - 2;
}
}
if (flags & moveflagPromotion) {
piece = (g_board[to] & (~0x7)) | piecePawn;
g_board[from] = piece;
var pawnType = g_board[from] & 0xF;
var promoteType = g_board[to] & 0xF;
g_pieceCount[promoteType]--;
var lastPromoteSquare = g_pieceList[(promoteType << 4) | g_pieceCount[promoteType]];
g_pieceIndex[lastPromoteSquare] = g_pieceIndex[to];
g_pieceList[(promoteType << 4) | g_pieceIndex[lastPromoteSquare]] = lastPromoteSquare;
g_pieceList[(promoteType << 4) | g_pieceCount[promoteType]] = 0;
g_pieceIndex[to] = g_pieceCount[pawnType];
g_pieceList[(pawnType << 4) | g_pieceIndex[to]] = to;
g_pieceCount[pawnType]++;
}
else {
g_board[from] = g_board[to];
}
var epcEnd = to;
if (flags & moveflagEPC) {
if (g_toMove == colorWhite)
epcEnd = to + 0x10;
else
epcEnd = to - 0x10;
g_board[to] = pieceEmpty;
}
g_board[epcEnd] = captured;
// Move our piece in the piece list
g_pieceIndex[from] = g_pieceIndex[to];
g_pieceList[((piece & 0xF) << 4) | g_pieceIndex[from]] = from;
if (captured) {
// Restore our piece to the piece list
var captureType = captured & 0xF;
g_pieceIndex[epcEnd] = g_pieceCount[captureType];
g_pieceList[(captureType << 4) | g_pieceCount[captureType]] = epcEnd;
g_pieceCount[captureType]++;
}
}
function ExposesCheck(from, kingPos){
var index = kingPos - from + 128;
// If a queen can't reach it, nobody can!
if ((g_vectorDelta[index].pieceMask[0] & (1 << (pieceQueen))) != 0) {
var delta = g_vectorDelta[index].delta;
var pos = kingPos + delta;
while (g_board[pos] == 0) pos += delta;
var piece = g_board[pos];
if (((piece & (g_board[kingPos] ^ 0x18)) & 0x18) == 0)
return false;
// Now see if the piece can actually attack the king
var backwardIndex = pos - kingPos + 128;
return (g_vectorDelta[backwardIndex].pieceMask[(piece >> 3) & 1] & (1 << (piece & 0x7))) != 0;
}
return false;
}
function IsSquareOnPieceLine(target, from) {
var index = from - target + 128;
var piece = g_board[from];
return (g_vectorDelta[index].pieceMask[(piece >> 3) & 1] & (1 << (piece & 0x7))) ? true : false;
}
function IsSquareAttackableFrom(target, from){
var index = from - target + 128;
var piece = g_board[from];
if (g_vectorDelta[index].pieceMask[(piece >> 3) & 1] & (1 << (piece & 0x7))) {
// Yes, this square is pseudo-attackable. Now, check for real attack
var inc = g_vectorDelta[index].delta;
do {
from += inc;
if (from == target)
return true;
} while (g_board[from] == 0);
}
return false;
}
function IsSquareAttackable(target, color) {
// Attackable by pawns?
var inc = color ? -16 : 16;
var pawn = (color ? colorWhite : colorBlack) | 1;
if (g_board[target - (inc - 1)] == pawn)
return true;
if (g_board[target - (inc + 1)] == pawn)
return true;
// Attackable by pieces?
for (var i = 2; i <= 6; i++) {
var index = (color | i) << 4;
var square = g_pieceList[index];
while (square != 0) {
if (IsSquareAttackableFrom(target, square))
return true;
square = g_pieceList[++index];
}
}
return false;
}
function GenerateMove(from, to) {
return from | (to << 8);
}
function GenerateMove(from, to, flags){
return from | (to << 8) | flags;
}
function GenerateValidMoves() {
var moveList = new Array();
var allMoves = new Array();
GenerateCaptureMoves(allMoves, null);
GenerateAllMoves(allMoves);
for (var i = allMoves.length - 1; i >= 0; i--) {
if (MakeMove(allMoves[i])) {
moveList[moveList.length] = allMoves[i];
UnmakeMove(allMoves[i]);
}
}
return moveList;
}
function GenerateAllMoves(moveStack) {
var from, to, piece, pieceIdx;
// Pawn quiet moves
pieceIdx = (g_toMove | 1) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
GeneratePawnMoves(moveStack, from);
from = g_pieceList[pieceIdx++];
}
// Knight quiet moves
pieceIdx = (g_toMove | 2) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from + 31; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 33; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 14; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 14; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 31; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 33; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 18; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 18; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
from = g_pieceList[pieceIdx++];
}
// Bishop quiet moves
pieceIdx = (g_toMove | 3) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from - 15; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to -= 15; }
to = from - 17; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to -= 17; }
to = from + 15; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to += 15; }
to = from + 17; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to += 17; }
from = g_pieceList[pieceIdx++];
}
// Rook quiet moves
pieceIdx = (g_toMove | 4) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from - 1; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to--; }
to = from + 1; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to++; }
to = from + 16; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to += 16; }
to = from - 16; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to -= 16; }
from = g_pieceList[pieceIdx++];
}
// Queen quiet moves
pieceIdx = (g_toMove | 5) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from - 15; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to -= 15; }
to = from - 17; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to -= 17; }
to = from + 15; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to += 15; }
to = from + 17; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to += 17; }
to = from - 1; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to--; }
to = from + 1; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to++; }
to = from + 16; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to += 16; }
to = from - 16; while (g_board[to] == 0) { moveStack[moveStack.length] = GenerateMove(from, to); to -= 16; }
from = g_pieceList[pieceIdx++];
}
// King quiet moves
{
pieceIdx = (g_toMove | 6) << 4;
from = g_pieceList[pieceIdx];
to = from - 15; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 17; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 15; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 17; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 1; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 1; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 16; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 16; if (g_board[to] == 0) moveStack[moveStack.length] = GenerateMove(from, to);
if (!g_inCheck) {
var castleRights = g_castleRights;
if (!g_toMove)
castleRights >>= 2;
if (castleRights & 1) {
// Kingside castle
if (g_board[from + 1] == pieceEmpty && g_board[from + 2] == pieceEmpty) {
moveStack[moveStack.length] = GenerateMove(from, from + 0x02, moveflagCastleKing);
}
}
if (castleRights & 2) {
// Queenside castle
if (g_board[from - 1] == pieceEmpty && g_board[from - 2] == pieceEmpty && g_board[from - 3] == pieceEmpty) {
moveStack[moveStack.length] = GenerateMove(from, from - 0x02, moveflagCastleQueen);
}
}
}
}
}
function GenerateCaptureMoves(moveStack, moveScores) {
var from, to, piece, pieceIdx;
var inc = (g_toMove == 8) ? -16 : 16;
var enemy = g_toMove == 8 ? 0x10 : 0x8;
// Pawn captures
pieceIdx = (g_toMove | 1) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from + inc - 1;
if (g_board[to] & enemy) {
MovePawnTo(moveStack, from, to);
}
to = from + inc + 1;
if (g_board[to] & enemy) {
MovePawnTo(moveStack, from, to);
}
from = g_pieceList[pieceIdx++];
}
if (g_enPassentSquare != -1) {
var inc = (g_toMove == colorWhite) ? -16 : 16;
var pawn = g_toMove | piecePawn;
var from = g_enPassentSquare - (inc + 1);
if ((g_board[from] & 0xF) == pawn) {
moveStack[moveStack.length] = GenerateMove(from, g_enPassentSquare, moveflagEPC);
}
from = g_enPassentSquare - (inc - 1);
if ((g_board[from] & 0xF) == pawn) {
moveStack[moveStack.length] = GenerateMove(from, g_enPassentSquare, moveflagEPC);
}
}
// Knight captures
pieceIdx = (g_toMove | 2) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from + 31; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 33; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 14; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 14; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 31; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 33; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 18; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 18; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
from = g_pieceList[pieceIdx++];
}
// Bishop captures
pieceIdx = (g_toMove | 3) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from; do { to -= 15; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to -= 17; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to += 15; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to += 17; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
from = g_pieceList[pieceIdx++];
}
// Rook captures
pieceIdx = (g_toMove | 4) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from; do { to--; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to++; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to -= 16; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to += 16; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
from = g_pieceList[pieceIdx++];
}
// Queen captures
pieceIdx = (g_toMove | 5) << 4;
from = g_pieceList[pieceIdx++];
while (from != 0) {
to = from; do { to -= 15; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to -= 17; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to += 15; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to += 17; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to--; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to++; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to -= 16; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from; do { to += 16; } while (g_board[to] == 0); if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
from = g_pieceList[pieceIdx++];
}
// King captures
{
pieceIdx = (g_toMove | 6) << 4;
from = g_pieceList[pieceIdx];
to = from - 15; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 17; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 15; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 17; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 1; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 1; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from - 16; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
to = from + 16; if (g_board[to] & enemy) moveStack[moveStack.length] = GenerateMove(from, to);
}
}
function MovePawnTo(moveStack, start, square) {
var row = square & 0xF0;
if ((row == 0x90) || (row == 0x20)) {
moveStack[moveStack.length] = GenerateMove(start, square, moveflagPromotion | moveflagPromoteQueen);
moveStack[moveStack.length] = GenerateMove(start, square, moveflagPromotion | moveflagPromoteKnight);
moveStack[moveStack.length] = GenerateMove(start, square, moveflagPromotion | moveflagPromoteBishop);
moveStack[moveStack.length] = GenerateMove(start, square, moveflagPromotion);
}
else {
moveStack[moveStack.length] = GenerateMove(start, square, 0);
}
}
function GeneratePawnMoves(moveStack, from) {
var piece = g_board[from];
var color = piece & colorWhite;
var inc = (color == colorWhite) ? -16 : 16;
// Quiet pawn moves
var to = from + inc;
if (g_board[to] == 0) {
MovePawnTo(moveStack, from, to, pieceEmpty);
// Check if we can do a 2 square jump
if ((((from & 0xF0) == 0x30) && color != colorWhite) ||
(((from & 0xF0) == 0x80) && color == colorWhite)) {
to += inc;
if (g_board[to] == 0) {
moveStack[moveStack.length] = GenerateMove(from, to);
}
}
}
}
function UndoHistory(ep, castleRights, inCheck, baseEval, hashKeyLow, hashKeyHigh, move50, captured) {
this.ep = ep;
this.castleRights = castleRights;
this.inCheck = inCheck;
this.baseEval = baseEval;
this.hashKeyLow = hashKeyLow;
this.hashKeyHigh = hashKeyHigh;
this.move50 = move50;
this.captured = captured;
}
var g_seeValues = [0, 1, 3, 3, 5, 9, 900, 0,
0, 1, 3, 3, 5, 9, 900, 0];
function See(move) {
var from = move & 0xFF;
var to = (move >> 8) & 0xFF;
var fromPiece = g_board[from];
var fromValue = g_seeValues[fromPiece & 0xF];
var toValue = g_seeValues[g_board[to] & 0xF];
if (fromValue <= toValue) {
return true;
}
if (move >> 16) {
// Castles, promotion, ep are always good
return true;
}
var us = (fromPiece & colorWhite) ? colorWhite : 0;
var them = 8 - us;
// Pawn attacks
// If any opponent pawns can capture back, this capture is probably not worthwhile (as we must be using knight or above).
var inc = (fromPiece & colorWhite) ? -16 : 16; // Note: this is capture direction from to, so reversed from normal move direction
if (((g_board[to + inc + 1] & 0xF) == (piecePawn | them)) ||
((g_board[to + inc - 1] & 0xF) == (piecePawn | them))) {
return false;
}
var themAttacks = new Array();
// Knight attacks
// If any opponent knights can capture back, and the deficit we have to make up is greater than the knights value,
// it's not worth it. We can capture on this square again, and the opponent doesn't have to capture back.
var captureDeficit = fromValue - toValue;
SeeAddKnightAttacks(to, them, themAttacks);
if (themAttacks.length != 0 && captureDeficit > g_seeValues[pieceKnight]) {
return false;
}
// Slider attacks
g_board[from] = 0;
for (var pieceType = pieceBishop; pieceType <= pieceQueen; pieceType++) {
if (SeeAddSliderAttacks(to, them, themAttacks, pieceType)) {
if (captureDeficit > g_seeValues[pieceType]) {
g_board[from] = fromPiece;
return false;
}
}
}
// Pawn defenses
// At this point, we are sure we are making a "losing" capture. The opponent can not capture back with a
// pawn. They cannot capture back with a minor/major and stand pat either. So, if we can capture with
// a pawn, it's got to be a winning or equal capture.
if (((g_board[to - inc + 1] & 0xF) == (piecePawn | us)) ||
((g_board[to - inc - 1] & 0xF) == (piecePawn | us))) {
g_board[from] = fromPiece;
return true;
}
// King attacks
SeeAddSliderAttacks(to, them, themAttacks, pieceKing);
// Our attacks
var usAttacks = new Array();
SeeAddKnightAttacks(to, us, usAttacks);
for (var pieceType = pieceBishop; pieceType <= pieceKing; pieceType++) {
SeeAddSliderAttacks(to, us, usAttacks, pieceType);
}
g_board[from] = fromPiece;
// We are currently winning the amount of material of the captured piece, time to see if the opponent
// can get it back somehow. We assume the opponent can capture our current piece in this score, which
// simplifies the later code considerably.
var seeValue = toValue - fromValue;
for (; ; ) {
var capturingPieceValue = 1000;
var capturingPieceIndex = -1;
// Find the least valuable piece of the opponent that can attack the square
for (var i = 0; i < themAttacks.length; i++) {
if (themAttacks[i] != 0) {
var pieceValue = g_seeValues[g_board[themAttacks[i]] & 0x7];
if (pieceValue < capturingPieceValue) {
capturingPieceValue = pieceValue;
capturingPieceIndex = i;
}
}
}
if (capturingPieceIndex == -1) {
// Opponent can't capture back, we win
return true;
}
// Now, if seeValue < 0, the opponent is winning. If even after we take their piece,
// we can't bring it back to 0, then we have lost this battle.
seeValue += capturingPieceValue;
if (seeValue < 0) {
return false;
}
var capturingPieceSquare = themAttacks[capturingPieceIndex];
themAttacks[capturingPieceIndex] = 0;
// Add any x-ray attackers
SeeAddXrayAttack(to, capturingPieceSquare, us, usAttacks, themAttacks);
// Our turn to capture
capturingPieceValue = 1000;
capturingPieceIndex = -1;
// Find our least valuable piece that can attack the square
for (var i = 0; i < usAttacks.length; i++) {
if (usAttacks[i] != 0) {
var pieceValue = g_seeValues[g_board[usAttacks[i]] & 0x7];
if (pieceValue < capturingPieceValue) {
capturingPieceValue = pieceValue;
capturingPieceIndex = i;
}
}
}
if (capturingPieceIndex == -1) {
// We can't capture back, we lose :(
return false;
}
// Assume our opponent can capture us back, and if we are still winning, we can stand-pat
// here, and assume we've won.
seeValue -= capturingPieceValue;
if (seeValue >= 0) {
return true;
}
capturingPieceSquare = usAttacks[capturingPieceIndex];
usAttacks[capturingPieceIndex] = 0;
// Add any x-ray attackers
SeeAddXrayAttack(to, capturingPieceSquare, us, usAttacks, themAttacks);
}
}
function SeeAddXrayAttack(target, square, us, usAttacks, themAttacks) {
var index = square - target + 128;
var delta = -g_vectorDelta[index].delta;
if (delta == 0)
return;
square += delta;
while (g_board[square] == 0) {
square += delta;
}
if ((g_board[square] & 0x18) && IsSquareOnPieceLine(target, square)) {
if ((g_board[square] & 8) == us) {
usAttacks[usAttacks.length] = square;
} else {
themAttacks[themAttacks.length] = square;
}
}
}
// target = attacking square, us = color of knights to look for, attacks = array to add squares to
function SeeAddKnightAttacks(target, us, attacks) {
var pieceIdx = (us | pieceKnight) << 4;
var attackerSq = g_pieceList[pieceIdx++];
while (attackerSq != 0) {
if (IsSquareOnPieceLine(target, attackerSq)) {
attacks[attacks.length] = attackerSq;
}
attackerSq = g_pieceList[pieceIdx++];
}
}
function SeeAddSliderAttacks(target, us, attacks, pieceType) {
var pieceIdx = (us | pieceType) << 4;
var attackerSq = g_pieceList[pieceIdx++];
var hit = false;
while (attackerSq != 0) {
if (IsSquareAttackableFrom(target, attackerSq)) {
attacks[attacks.length] = attackerSq;
hit = true;
}
attackerSq = g_pieceList[pieceIdx++];
}
return hit;
}
function BuildPVMessage(bestMove, value, timeTaken, ply) {
var totalNodes = g_nodeCount + g_qNodeCount;
return "Ply:" + ply + " Score:" + value + " Nodes:" + totalNodes + " NPS:" + ((totalNodes / (timeTaken / 1000)) | 0) + " " + PVFromHash(bestMove, 15);
}
//////////////////////////////////////////////////
// Test Harness
//////////////////////////////////////////////////
function FinishPlyCallback(bestMove, value, timeTaken, ply) {
postMessage("pv " + BuildPVMessage(bestMove, value, timeTaken, ply));
}
function FinishMoveLocalTesting(bestMove, value, timeTaken, ply) {
if (bestMove != null) {
MakeMove(bestMove);
postMessage(FormatMove(bestMove));
}
}
var needsReset = true;
self.onmessage = function (e) {
if (e.data == "go" || needsReset) {
ResetGame();
needsReset = false;
if (e.data == "go") return;
}
if (typeof e.data !== 'undefined') {
if (e.data.match("^position") == "position") {
ResetGame();
var result = InitializeFromFen(e.data.substr(9, e.data.length - 9));
if (result.length != 0) {
postMessage("message " + result);
}
} else if (e.data.match("^search") == "search") {
g_timeout = parseInt(e.data.substr(7, e.data.length - 7), 10);
Search(FinishMoveLocalTesting, 99, FinishPlyCallback);
} else if (e.data == "analyze") {
g_timeout = 99999999999;
Search(null, 99, FinishPlyCallback);
} else {
MakeMove(GetMoveFromString(e.data));
}
}
};
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