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Diffstat (limited to 'js/AI/garbochess.js')
| -rw-r--r-- | js/AI/garbochess.js | 2738 |
1 files changed, 2738 insertions, 0 deletions
diff --git a/js/AI/garbochess.js b/js/AI/garbochess.js new file mode 100644 index 0000000..ef0ff9b --- /dev/null +++ b/js/AI/garbochess.js @@ -0,0 +1,2738 @@ +/* +This Chess AI comes from here +https://github.com/glinscott/Garbochess-JS + +Copyright (c) 2011 Gary Linscott +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions +are met: +1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. +2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. +3. The name of the author may not be used to endorse or promote products + derived from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR +IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, +INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +// 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) + + +// ECMAScript 5 strict mode +/* jshint globalstrict: true*/ +/* jslint newcap: true */ +/* global postMessage, self */ +"use strict"; + +var g_debug = false; +var g_timeout = 40; +var g_maxply = 99; +var worker = false; +try { + // not sure this will work on any browser + // and since it's just for debug, + // a try catch should be good enough + if ( self.constructor.name === "DedicatedWorkerContext") { + worker = true; + } +} catch(e) {} + +debug ("worker = "+worker); + +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 === undefined) { + 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 !== undefined && hashNode.lock === g_hashKeyHigh && hashNode.bestMove !== undefined) { + 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) { + debug("start search with maxPly:"+maxPly+" and timeout "+g_timeout); + + if (GenerateValidMoves().length === 0) { + debug( g_inCheck ? 'Checkmate' : 'Stalemate' ); + return false; + } + + 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] !== undefined) { + bestMove = g_hashTable[g_hashKeyLow & g_hashMask].bestMove; + } + + if (finishPlyCallback !== undefined) { + finishPlyCallback(bestMove, value, (new Date()).getTime() - g_startTime, i); + } + } + + if (finishMoveCallback !== undefined) { + 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 = []; + var moveScores = []; + var wasInCheck = g_inCheck; + var i; + + if (wasInCheck) { + // TODO: Fast check escape generator and fast checking moves generator + GenerateCaptureMoves(moves, null); + GenerateAllMoves(moves); + + for (i = 0; i < moves.length; i++) { + moveScores[i] = ScoreMove(moves[i]); + } + } else { + GenerateCaptureMoves(moves, null); + + for (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 (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 = []; + 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 = []; + this.losingCaptures = null; + this.moveCount = 0; + this.atMove = -1; + this.moveScores = null; + this.stage = 0; + + this.nextMove = function () { + var i; + if (++this.atMove == this.moveCount) { + this.stage++; + if (this.stage == 1) { + if (this.hashMove !== undefined && IsHashMoveValid(hashMove)) { + this.moves[0] = hashMove; + this.moveCount = 1; + } + if (this.moveCount != 1) { + this.hashMove = undefined; + this.stage++; + } + } + + if (this.stage == 2) { + GenerateCaptureMoves(this.moves, null); + this.moveCount = this.moves.length; + this.moveScores = new Array(this.moveCount); + // Move ordering + for (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 (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 (i = 0; i < this.losingCaptures.length; i++) { + this.moves[this.moves.length] = this.losingCaptures[i]; + } + for (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 = []; + } + 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 !== undefined && 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? + var value; + if (!g_inCheck && + allowNull && + beta > minMateBuffer && + beta < maxMateBuffer) { + // Try some razoring + if (hashMove === undefined && + 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; + + 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; + } + + value = null; + 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 !== undefined && 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 moveflagPromoteRook = 0x00 << 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; + var i,s,k; + switch (a.length) { + case 1: + if (a[0].constructor === Number) { + this.mt[0]= a[0]; + for (i = 1; i < N; ++i) { + 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 j = 0; + i = 1; + + for (k = N > l ? N : l; k !== 0; --k) { + 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 (k = N - 1; k !== 0; --k) { + 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 = []; + for (i = 0; i < a.length; ++i) { + seeds.push(a[i]); + } + this.setSeed(seeds); + return; + } + }; + + this.setSeed(0x1BADF00D); + + this.next = function (bits) + { + var k; + if (this.mti >= N) { + var x = 0; + + for (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 (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 = []; + +var g_move50 = 0; +var g_repMoveStack = []; + +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(fen) { + var i,j; + var row, col; + var square; + g_killers = new Array(128); + + for (i = 0; i < 128; i++) { + g_killers[i] = [0, 0]; + } + + g_hashTable = new Array(g_hashSize); + + for (i = 0; i < 32; i++) { + historyTable[i] = new Array(256); + for (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 (i = 0; i < 256; i++) { + g_zobristLow[i] = new Array(16); + g_zobristHigh[i] = new Array(16); + for (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 (row = 0; row < 8; row++) { + for (col = 0; col < 8; col++) { + 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 (i = 0; i < 256; i++) { + g_vectorDelta[i] = {}; + 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 (row = 0; row < 0x80; row += 0x10) + for (col = 0; col < 0x8; col++) { + 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 (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] = []; + 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 = {}; + 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 i; + var row = 0; + var col = 0; + var chunks = fen.split(' '); + + for (i = 0; i < 256; i++) + g_board[i] = 0x80; + + + var pieces = chunks[0]; + for (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,10); 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) { + col = chunks[3].charAt(0).charCodeAt() - 'a'.charCodeAt(); + 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 (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() { + var i; + for (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 (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){ + // move format: + // --flags-- ---to---- --from--- + // 0000 0000 0000 0000 0000 0000 + + // g_board is a 256x256 array + // representing the chess board + // right in the middle of it + + // moveflagEPC = 0000 0010 0000 0000 0000 0000 + // moveflagCastleKing = 0000 0100 0000 0000 0000 0000 + // moveflagCastleQueen = 0000 1000 0000 0000 0000 0000 + + // moveflagPromotion = 0001 0000 0000 0000 0000 0000 + // moveflagPromoteRook = 0000 0000 0000 0000 0000 0000 + // moveflagPromoteKnight = 0010 0000 0000 0000 0000 0000 + // moveflagPromoteQueen = 0100 0000 0000 0000 0000 0000 + // moveflagPromoteBishop = 1000 0000 0000 0000 0000 0000 + + + 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; + var rook, rookIndex; + + 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; + } + + 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)]; + + 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; + } + + 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)]; + + rookIndex = g_pieceIndex[to - 2]; + g_pieceIndex[to + 1] = rookIndex; + g_pieceList[((rook & 0xF) << 4) | rookIndex] = to + 1; + } + } + + if ((captured & 0x7) > 0) { + // 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]; + var rook,rookIndex; + + if (flags) { + if (flags & moveflagCastleKing) { + rook = g_board[to - 1]; + g_board[to + 1] = rook; + g_board[to - 1] = pieceEmpty; + + rookIndex = g_pieceIndex[to - 1]; + g_pieceIndex[to + 1] = rookIndex; + g_pieceList[((rook & 0xF) << 4) | rookIndex] = to + 1; + } + else if (flags & moveflagCastleQueen) { + rook = g_board[to + 1]; + g_board[to - 2] = rook; + g_board[to + 1] = pieceEmpty; + + 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 = []; + var allMoves = []; + 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]); + } else { + } + } + + 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) { + inc = (g_toMove === colorWhite) ? -16 : 16; + var pawn = g_toMove | piecePawn; + + 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]; + var pieceType,pieceValue,i; + + 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 = []; + + // 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 (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 = []; + SeeAddKnightAttacks(to, us, usAttacks); + for (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 (i = 0; i < themAttacks.length; i++) { + if (themAttacks[i] !== 0) { + 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 (i = 0; i < usAttacks.length; i++) { + if (usAttacks[i] !== 0) { + 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 !== undefined) { + 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 (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") { + var level = e.data.substr(7,e.data.length-7).split(","); + g_timeout = parseInt(level[0], 10); + g_maxply = parseInt(level[1], 10); + Search(FinishMoveLocalTesting, g_maxply, FinishPlyCallback); + } else if (e.data == "analyze") { + g_timeout = 99999999999; + Search(null, g_maxply, FinishPlyCallback); + } else { + MakeMove(GetMoveFromString(e.data)); + } +}; + +function debug(msg) { + if (g_debug) { + if(worker) { + postMessage("console: "+msg); + } else { + console.log(msg); + } + } +}
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