4 files changed, 39 insertions, 22 deletions

diff --git a/src/board/board.cpp b/src/board/board.cpp
index 92d448d..cb9254e 100644
--- a/src/board/board.cpp
+++ b/src/board/board.cpp
@@ -195,7 +195,7 @@ UndoMove MakeMove(Move move, Game *g) {
   if (g->halfMoveClock >= 50) {
     g->state = DRAW;
   }
-
+  UpdateBitboards(g);
   return undo;
 };
 void UnMakeMove(UndoMove undo, Game *g) {
@@ -251,4 +251,15 @@ void UnMakeMove(UndoMove undo, Game *g) {
   if (g->ThreeFoldMap[undo.ZobristKey] <= 0) {
     g->ThreeFoldMap.erase(undo.ZobristKey);
   };
+  UpdateBitboards(g);
 };
+void UpdateBitboards(Game *g) {
+  g->PieceBitboard = 0;
+  for (int i = 0; i < 64; i++) {
+    Piece piece = g->pieces[i];
+    if (piece.type == NONEPIECE) {
+      continue;
+    }
+    g->PieceBitboard |= (1ULL << i);
+  }
+}
diff --git a/src/board/board.hpp b/src/board/board.hpp
index d1e379a..91a38f9 100644
--- a/src/board/board.hpp
+++ b/src/board/board.hpp
@@ -52,7 +52,8 @@ struct TranspositionsEntry {
 };
 struct Game {
   Piece pieces[64];
-  bool turn = true; // 1 white; 0 black
+  uint64_t PieceBitboard = 0; // used for quicly iterating over all squares
+  bool turn = true;           // 1 white; 0 black
   bool whiteCastleKing = false;
   bool whiteCastleQueen = false;
   bool blackCastleKing = false;
@@ -101,5 +102,6 @@ int PositionToIndex(Position i);
 UndoMove MakeMove(Move move, Game *g);
 void UnMakeMove(UndoMove undo, Game *g);
 
-Position FindKing(Game *b, bool white);
+Position FindKing(Game *g, bool white);
+void UpdateBitboards(Game *g);
 #endif /* SRC_BOARD_H_ */
diff --git a/src/board/fen.cpp b/src/board/fen.cpp
index 4b8686e..91a2533 100644
--- a/src/board/fen.cpp
+++ b/src/board/fen.cpp
@@ -8,7 +8,7 @@
 bool WHITE = true;
 bool BLACK = false;
 
-void setBoardFen(std::string fen, Game *b) {
+void setBoardFen(std::string fen, Game *g) {
   // example fen rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
   int file = 0;
   int rank = 0;
@@ -51,36 +51,36 @@ void setBoardFen(std::string fen, Game *b) {
     }
     if (state == CASTLE) {
       if (fen[i] == '-') {
-        b->blackCastleKing = false;
-        b->blackCastleQueen = false;
-        b->whiteCastleKing = false;
-        b->whiteCastleQueen = false;
+        g->blackCastleKing = false;
+        g->blackCastleQueen = false;
+        g->whiteCastleKing = false;
+        g->whiteCastleQueen = false;
         continue;
       }
       if (fen[i] == 'K') {
-        b->whiteCastleKing = true;
+        g->whiteCastleKing = true;
         continue;
       }
       if (fen[i] == 'Q') {
-        b->whiteCastleQueen = true;
+        g->whiteCastleQueen = true;
         continue;
       }
       if (fen[i] == 'k') {
-        b->blackCastleKing = true;
+        g->blackCastleKing = true;
         continue;
       }
       if (fen[i] == 'q') {
-        b->blackCastleQueen = true;
+        g->blackCastleQueen = true;
         continue;
       }
     }
     if (state == TURN) {
       if (toupper(fen[i]) == 'W') {
-        b->turn = WHITE;
+        g->turn = WHITE;
         continue;
       }
       if (toupper(fen[i]) == 'B') {
-        b->turn = BLACK;
+        g->turn = BLACK;
         continue;
       }
     }
@@ -107,41 +107,42 @@ void setBoardFen(std::string fen, Game *b) {
       };
       if (toupper(fen[i]) == 'N') {
         Piece piece = createPiece(KNIGHT, isupper(fen[i]));
-        b->pieces[rank * 8 + file] = piece;
+        g->pieces[rank * 8 + file] = piece;
         file++;
         continue;
       };
       if (toupper(fen[i]) == 'R') {
         Piece piece = createPiece(ROOK, isupper(fen[i]));
-        b->pieces[rank * 8 + file] = piece;
+        g->pieces[rank * 8 + file] = piece;
         file++;
         continue;
       }
       if (toupper(fen[i]) == 'Q') {
         Piece piece = createPiece(QUEEN, isupper(fen[i]));
-        b->pieces[rank * 8 + file] = piece;
+        g->pieces[rank * 8 + file] = piece;
         file++;
         continue;
       }
       if (toupper(fen[i]) == 'B') {
         Piece piece = createPiece(BISHOP, isupper(fen[i]));
-        b->pieces[rank * 8 + file] = piece;
+        g->pieces[rank * 8 + file] = piece;
         file++;
         continue;
       }
       if (toupper(fen[i]) == 'P') {
         Piece piece = createPiece(PAWN, isupper(fen[i]));
-        b->pieces[rank * 8 + file] = piece;
+        g->pieces[rank * 8 + file] = piece;
         file++;
         continue;
       }
       if (toupper(fen[i]) == 'K') {
         Piece piece = createPiece(KING, isupper(fen[i]));
-        b->pieces[rank * 8 + file] = piece;
+        g->pieces[rank * 8 + file] = piece;
         file++;
         continue;
       }
     }
     break;
   }
+  UpdateBitboards(g);
 }
diff --git a/src/moves.cpp b/src/moves.cpp
index fc2b8c7..84c5ba4 100644
--- a/src/moves.cpp
+++ b/src/moves.cpp
@@ -147,10 +147,13 @@ std::vector<Move> GetPseudoLegalMoves(Game *b, bool GenerateQuietMoves) {
   constexpr std::array<int, 4> rook_Moves{-1, 1, 8, -8};
   constexpr std::array<int, 4> bishop_Moves{-9, 9, -7, 7};
 
-  for (uint i = 0; i < sizeof(b->pieces) / sizeof(b->pieces[0]); i++) {
+  uint64_t piece_bitboard = b->PieceBitboard;
+  while (piece_bitboard != 0) {
+    int i = __builtin_ctzll(piece_bitboard);
+    piece_bitboard &= piece_bitboard - 1;
     Piece piece = b->pieces[i];
     if (piece.type == NONEPIECE) {
-      continue;
+      assert(false && "got none piece in piece bitboard");
     }
     if (piece.color != b->turn) {
       continue;