X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=99b6076cba3d6ed2321cbcd1db529eb43fb84a61;hp=abcafc00b5b0c6379f475eef5fd34d0c386e3609;hb=35fd5ce5bc3b2a99369e277a83b4426ab3bc5bc2;hpb=f56af8e84db25c0d26fe762fbe171ec5518177bb

diff --git a/src/movegen.cpp b/src/movegen.cpp
index abcafc00..99b6076c 100644
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -32,22 +32,15 @@
 
 namespace {
   
-  int generate_white_pawn_captures(const Position &pos, MoveStack *mlist);
-  int generate_black_pawn_captures(const Position &pos, MoveStack *mlist);
-  int generate_white_pawn_noncaptures(const Position &pos, MoveStack *mlist);
-  int generate_black_pawn_noncaptures(const Position &pos, MoveStack *mlist);
-  int generate_knight_moves(const Position &pos, MoveStack *mlist, 
-                            Color side, Bitboard target);
-  int generate_bishop_moves(const Position &pos, MoveStack *mlist, 
-                            Color side, Bitboard target);
-  int generate_rook_moves(const Position &pos, MoveStack *mlist, 
-                          Color side, Bitboard target);
-  int generate_queen_moves(const Position &pos, MoveStack *mlist, 
-                           Color side, Bitboard target);
-  int generate_king_moves(const Position &pos, MoveStack *mlist, 
-                          Square from, Bitboard target);
-  int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us);
-
+  int generate_white_pawn_captures(const Position&, MoveStack*);
+  int generate_black_pawn_captures(const Position&, MoveStack*);
+  int generate_white_pawn_noncaptures(const Position&, MoveStack*);
+  int generate_black_pawn_noncaptures(const Position&, MoveStack*);
+  int generate_piece_moves(PieceType, const Position&, MoveStack*, Color side, Bitboard t);
+  int generate_castle_moves(const Position&, MoveStack*, Color us);
+
+  int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target,
+                            Bitboard dc, Square ksq, MoveStack* mlist);
 }
 
 
@@ -59,23 +52,22 @@ namespace {
 /// generate_captures generates() all pseudo-legal captures and queen
 /// promotions.  The return value is the number of moves generated.
 
-int generate_captures(const Position &pos, MoveStack *mlist) {
-  Color us = pos.side_to_move();
-  Bitboard target = pos.pieces_of_color(opposite_color(us));
-  int n = 0;
+int generate_captures(const Position& pos, MoveStack* mlist) {
 
   assert(pos.is_ok());
   assert(!pos.is_check());
 
-  if(us == WHITE)
-    n += generate_white_pawn_captures(pos, mlist);
+  Color us = pos.side_to_move();
+  Bitboard target = pos.pieces_of_color(opposite_color(us));
+  int n;
+
+  if (us == WHITE)
+      n = generate_white_pawn_captures(pos, mlist);
   else
-    n += generate_black_pawn_captures(pos, mlist);
-  n += generate_knight_moves(pos, mlist+n, us, target);
-  n += generate_bishop_moves(pos, mlist+n, us, target);
-  n += generate_rook_moves(pos, mlist+n, us, target);
-  n += generate_queen_moves(pos, mlist+n, us, target);
-  n += generate_king_moves(pos, mlist+n, pos.king_square(us), target);
+      n = generate_black_pawn_captures(pos, mlist);
+
+  for (PieceType pce = KNIGHT; pce <= KING; pce++)
+      n += generate_piece_moves(pce, pos, mlist+n, us, target);
 
   return n;
 }
@@ -84,25 +76,24 @@ int generate_captures(const Position &pos, MoveStack *mlist) {
 /// generate_noncaptures() generates all pseudo-legal non-captures and 
 /// underpromotions.  The return value is the number of moves generated.
 
-int generate_noncaptures(const Position &pos, MoveStack *mlist) {
-  Color us = pos.side_to_move();
-  Bitboard target = pos.empty_squares();
-  int n = 0;
+int generate_noncaptures(const Position& pos, MoveStack *mlist) {
 
   assert(pos.is_ok());
   assert(!pos.is_check());
 
-  if(us == WHITE)
-    n += generate_white_pawn_noncaptures(pos, mlist);
+  Color us = pos.side_to_move();
+  Bitboard target = pos.empty_squares();
+  int n;
+
+  if (us == WHITE)
+      n = generate_white_pawn_noncaptures(pos, mlist);
   else
-    n += generate_black_pawn_noncaptures(pos, mlist);
-  n += generate_knight_moves(pos, mlist+n, us, target);
-  n += generate_bishop_moves(pos, mlist+n, us, target);
-  n += generate_rook_moves(pos, mlist+n, us, target);
-  n += generate_queen_moves(pos, mlist+n, us, target);
-  n += generate_king_moves(pos, mlist+n, pos.king_square(us), target);
-  n += generate_castle_moves(pos, mlist+n, us);
+      n = generate_black_pawn_noncaptures(pos, mlist);
 
+  for (PieceType pce = KNIGHT; pce <= KING; pce++)
+      n += generate_piece_moves(pce, pos, mlist+n, us, target);
+
+  n += generate_castle_moves(pos, mlist+n, us);
   return n;
 }
 
@@ -111,15 +102,16 @@ int generate_noncaptures(const Position &pos, MoveStack *mlist) {
 /// checks, except castling moves (will add this later).  It returns the
 /// number of generated moves.  
 
-int generate_checks(const Position &pos, MoveStack *mlist, Bitboard dc) {
-  Color us, them;
-  Square ksq, from, to;
-  Bitboard empty, checkSqs, b1, b2, b3;
-  int n = 0;
+int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
 
   assert(pos.is_ok());
   assert(!pos.is_check());
 
+  Color us, them;
+  Square ksq, from, to;
+  Bitboard empty, b1, b2, b3;
+  int n = 0;
+
   us = pos.side_to_move();
   them = opposite_color(us);
 
@@ -132,46 +124,51 @@ int generate_checks(const Position &pos, MoveStack *mlist, Bitboard dc) {
   // Pawn moves.  This is somewhat messy, and we use separate code for white
   // and black, because we can't shift by negative numbers in C/C++.  :-(
 
-  if(us == WHITE) {
-    // Pawn moves which give discovered check.  This is possible only if the 
+  if (us == WHITE)
+  {
+    // Pawn moves which give discovered check. This is possible only if the 
     // pawn is not on the same file as the enemy king, because we don't 
     // generate captures.
 
-    // Find all friendly pawns not on the enemy king's file:
+    // Find all friendly pawns not on the enemy king's file
     b1 = pos.pawns(us) & ~file_bb(ksq);
 
-    // Discovered checks, single pawn pushes:
+    // Discovered checks, single pawn pushes
     b2 = b3 = ((b1 & dc) << 8) & ~Rank8BB & empty;
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_N, to);
+    while (b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_N, to);
     }
 
-    // Discovered checks, double pawn pushes:
+    // Discovered checks, double pawn pushes
     b3 = ((b2 & Rank3BB) << 8) & empty;
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
+    while (b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
     }
 
-    // Direct checks.  These are possible only for pawns on neighboring files
-    // of the enemy king:
+    // Direct checks. These are possible only for pawns on neighboring files
+    // of the enemy king
 
     b1 &= (~dc & neighboring_files_bb(ksq));
 
-    // Direct checks, single pawn pushes:
+    // Direct checks, single pawn pushes
     b2 = (b1 << 8) & empty;
     b3 = b2 & pos.black_pawn_attacks(ksq);
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_N, to);
+    while(b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_N, to);
     }
 
-    // Direct checks, double pawn pushes:
+    // Direct checks, double pawn pushes
     b3 = ((b2 & Rank3BB) << 8) & empty & pos.black_pawn_attacks(ksq);
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
+    while (b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
     }
   }
   else { // (us == BLACK)
@@ -183,147 +180,75 @@ int generate_checks(const Position &pos, MoveStack *mlist, Bitboard dc) {
     // Find all friendly pawns not on the enemy king's file:
     b1 = pos.pawns(us) & ~file_bb(ksq);
 
-    // Discovered checks, single pawn pushes:
+    // Discovered checks, single pawn pushes
     b2 = b3 = ((b1 & dc) >> 8) & ~Rank1BB & empty;
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_S, to);
+    while (b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_S, to);
     }
 
-    // Discovered checks, double pawn pushes:
+    // Discovered checks, double pawn pushes
     b3 = ((b2 & Rank6BB) >> 8) & empty;
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
+    while (b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
     }
 
     // Direct checks.  These are possible only for pawns on neighboring files
-    // of the enemy king:
+    // of the enemy king
 
     b1 &= (~dc & neighboring_files_bb(ksq));
 
     // Direct checks, single pawn pushes:
     b2 = (b1 >> 8) & empty;
     b3 = b2 & pos.white_pawn_attacks(ksq);
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_S, to);
+    while (b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_S, to);
     }
 
-    // Direct checks, double pawn pushes:
+    // Direct checks, double pawn pushes
     b3 = ((b2 & Rank6BB) >> 8) & empty & pos.black_pawn_attacks(ksq);
-    while(b3) {
-      to = pop_1st_bit(&b3);
-      mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
+    while (b3)
+    {
+        to = pop_1st_bit(&b3);
+        mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
     }
   }
 
   // Knight moves
   b1 = pos.knights(us);
-  if(b1) {
-    // Discovered knight checks:
-    b2 = b1 & dc;
-    while(b2) {
-      from = pop_1st_bit(&b2);
-      b3 = pos.knight_attacks(from) & empty;
-      while(b3) {
-        to = pop_1st_bit(&b3);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-    
-    // Direct knight checks:
-    b2 = b1 & ~dc;
-    checkSqs = pos.knight_attacks(ksq) & empty;
-    while(b2) {
-      from = pop_1st_bit(&b2);
-      b3 = pos.knight_attacks(from) & checkSqs;
-      while(b3) {
-        to = pop_1st_bit(&b3);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-  }
+  if (b1)
+      n += generate_piece_checks(KNIGHT, pos, b1, dc, ksq, mlist);
 
   // Bishop moves
   b1 = pos.bishops(us);
-  if(b1) {
-    // Discovered bishop checks:
-    b2 = b1 & dc;
-    while(b2) {
-      from = pop_1st_bit(&b2);
-      b3 = pos.bishop_attacks(from) & empty;
-      while(b3) {
-        to = pop_1st_bit(&b3);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-    
-    // Direct bishop checks:
-    b2 = b1 & ~dc;
-    checkSqs = pos.bishop_attacks(ksq) & empty;
-    while(b2) {
-      from = pop_1st_bit(&b2);
-      b3 = pos.bishop_attacks(from) & checkSqs;
-      while(b3) {
-        to = pop_1st_bit(&b3);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-  }
+  if (b1)
+      n += generate_piece_checks(BISHOP, pos, b1, dc, ksq, mlist);
 
   // Rook moves
   b1 = pos.rooks(us);
-  if(b1) {
-    // Discovered rook checks:
-    b2 = b1 & dc;
-    while(b2) {
-      from = pop_1st_bit(&b2);
-      b3 = pos.rook_attacks(from) & empty;
-      while(b3) {
-        to = pop_1st_bit(&b3);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-    
-    // Direct rook checks:
-    b2 = b1 & ~dc;
-    checkSqs = pos.rook_attacks(ksq) & empty;
-    while(b2) {
-      from = pop_1st_bit(&b2);
-      b3 = pos.rook_attacks(from) & checkSqs;
-      while(b3) {
-        to = pop_1st_bit(&b3);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-  }
+  if (b1)
+      n += generate_piece_checks(ROOK, pos, b1, dc, ksq, mlist);
 
   // Queen moves
   b1 = pos.queens(us);
-  if(b1) {
-    // Discovered queen checks are impossible!
-
-    // Direct queen checks:
-    checkSqs = pos.queen_attacks(ksq) & empty;
-    while(b1) {
-      from = pop_1st_bit(&b1);
-      b2 = pos.queen_attacks(from) & checkSqs;
-      while(b2) {
-        to = pop_1st_bit(&b2);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-  }
+  if (b1)
+      n += generate_piece_checks(QUEEN, pos, b1, dc, ksq, mlist);
 
   // King moves
   from = pos.king_square(us);
-  if(bit_is_set(dc, from)) {
-    b1 = pos.king_attacks(from) & empty & ~QueenPseudoAttacks[ksq];
-    while(b1) {
-      to = pop_1st_bit(&b1);
-      mlist[n++].move = make_move(from, to);
-    }
+  if (bit_is_set(dc, from))
+  {
+      b1 = pos.king_attacks(from) & empty & ~QueenPseudoAttacks[ksq];
+      while (b1)
+      {
+          to = pop_1st_bit(&b1);
+          mlist[n++].move = make_move(from, to);
+      }
   }
 
   // TODO: Castling moves!
@@ -338,15 +263,16 @@ int generate_checks(const Position &pos, MoveStack *mlist, Bitboard dc) {
 /// function is very ugly, and needs cleaning up some time later.  FIXME
 
 int generate_evasions(const Position &pos, MoveStack *mlist) {
+
+  assert(pos.is_ok());
+  assert(pos.is_check());
+
   Color us, them;
   Bitboard checkers = pos.checkers();
   Bitboard pinned, b1, b2;
   Square ksq, from, to;
   int n = 0;
 
-  assert(pos.is_ok());
-  assert(pos.is_check());
-
   us = pos.side_to_move();
   them = opposite_color(us);
 
@@ -575,27 +501,25 @@ int generate_evasions(const Position &pos, MoveStack *mlist) {
 /// very hard to write an efficient legal move generator, but for the moment
 /// we don't need it.
 
-int generate_legal_moves(const Position &pos, MoveStack *mlist) {
+int generate_legal_moves(const Position& pos, MoveStack* mlist) {
+
   assert(pos.is_ok());
 
-  if(pos.is_check())
-    return generate_evasions(pos, mlist);
-  else {
-    int i, n;
-    Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+  if (pos.is_check())
+      return generate_evasions(pos, mlist);
 
-    // Generate pseudo-legal moves:
-    n = generate_captures(pos, mlist);
-    n += generate_noncaptures(pos, mlist + n);
+  // Generate pseudo-legal moves:
+  int n = generate_captures(pos, mlist);
+  n += generate_noncaptures(pos, mlist + n);
 
-    // Remove illegal moves from the list:
-    for(i = 0; i < n; i++) {
-      if(!pos.move_is_legal(mlist[i].move, pinned))
-        mlist[i--].move = mlist[--n].move;
-    }
+  Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
 
-    return n;
-  }
+  // Remove illegal moves from the list:
+  for (int i = 0; i < n; i++)
+      if (!pos.move_is_legal(mlist[i].move, pinned))
+          mlist[i--].move = mlist[--n].move;
+
+  return n;
 }
 
 
@@ -606,387 +530,320 @@ int generate_legal_moves(const Position &pos, MoveStack *mlist) {
 /// only be used when the side to move is not in check.
 
 Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
-  Color us, them;
-  Square from, to;
-  Piece pc;
 
   assert(pos.is_ok());
   assert(!pos.is_check());
   assert(move_is_ok(m));
 
-  us = pos.side_to_move();
-  them = opposite_color(us);
-  from = move_from(m);
-  pc = pos.piece_on(from);
+  Color us = pos.side_to_move();
+  Color them = opposite_color(us);
+  Square from = move_from(m);
+  Piece pc = pos.piece_on(from);
 
   // If the from square is not occupied by a piece belonging to the side to
   // move, the move is obviously not legal.
-  if(color_of_piece(pc) != us )
-    return MOVE_NONE;
+  if (color_of_piece(pc) != us)
+      return MOVE_NONE;
 
-  to = move_to(m);
+  Square to = move_to(m);
 
-  // En passant moves:
-  if(move_is_ep(m)) {
+  // En passant moves
+  if (move_is_ep(m))
+  {
+      // The piece must be a pawn and destination square must be the
+      // en passant square.
+      if (   type_of_piece(pc) != PAWN
+          || to != pos.ep_square())
+          return MOVE_NONE;
 
-    // The piece must be a pawn:
-    if(type_of_piece(pc) != PAWN)
-      return MOVE_NONE;
+      assert(pos.square_is_empty(to));
+      assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them));
 
-    // The destination square must be the en passant square:
-    if(to != pos.ep_square())
-      return MOVE_NONE;
+      // The move is pseudo-legal.  If it is legal, return it.
+      return (pos.move_is_legal(m) ? m : MOVE_NONE);
+  }
 
-    assert(pos.square_is_empty(to));
-    assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them));
+  // Castling moves
+  if (move_is_short_castle(m))
+  {
+      // The piece must be a king and side to move must still have
+      // the right to castle kingside.
+      if (   type_of_piece(pc) != KING
+          ||!pos.can_castle_kingside(us))
+          return MOVE_NONE;
 
-    // The move is pseudo-legal.  If it is legal, return it.
-    if(pos.move_is_legal(m))
-      return m;
-    else
-      return MOVE_NONE;
+      assert(from == pos.king_square(us));
+      assert(to == pos.initial_kr_square(us));
+      assert(pos.piece_on(to) == rook_of_color(us));
+
+      Square g1 = relative_square(us, SQ_G1);
+      Square f1 = relative_square(us, SQ_F1);
+      Square s;
+      bool illegal = false;
+
+      // Check if any of the squares between king and rook
+      // is occupied or under attack.
+      for (s = Min(from, g1); s <= Max(from, g1); s++)
+          if (  (s != from && s != to && !pos.square_is_empty(s))
+              || pos.square_is_attacked(s, them))
+              illegal = true;
+
+      // Check if any of the squares between king and rook
+      // is occupied.
+      for (s = Min(to, f1); s <= Max(to, f1); s++)
+          if (s != from && s != to && !pos.square_is_empty(s))
+              illegal = true;
+
+      return (!illegal ? m : MOVE_NONE);
   }
 
-  // Castling moves:
-  else if(move_is_short_castle(m)) {
+  if (move_is_long_castle(m))
+  {
+      // The piece must be a king and side to move must still have
+      // the right to castle kingside.
+      if (   type_of_piece(pc) != KING
+          ||!pos.can_castle_queenside(us))
+          return MOVE_NONE;
 
-    // The piece must be a king:
-    if(type_of_piece(pc) != KING)
-      return MOVE_NONE;
+      assert(from == pos.king_square(us));
+      assert(to == pos.initial_qr_square(us));
+      assert(pos.piece_on(to) == rook_of_color(us));
 
-    // The side to move must still have the right to castle kingside:
-    if(!pos.can_castle_kingside(us))
-      return MOVE_NONE;
+      Square c1 = relative_square(us, SQ_C1);
+      Square d1 = relative_square(us, SQ_D1);
+      Square s;
+      bool illegal = false;
 
-    assert(from == pos.king_square(us));
-    assert(to == pos.initial_kr_square(us));
-    assert(pos.piece_on(to) == rook_of_color(us));
-
-    Square g1 = relative_square(us, SQ_G1);
-    Square f1 = relative_square(us, SQ_F1);
-    Square s;
-    bool illegal = false;
-
-    for(s = Min(from, g1); s <= Max(from, g1); s++)
-      if((s != from && s != to && !pos.square_is_empty(s)) ||
-         pos.square_is_attacked(s, them))
-        illegal = true;
-    for(s = Min(to, f1); s <= Max(to, f1); s++)
-      if(s != from && s != to && !pos.square_is_empty(s))
-        illegal = true;
-
-    if(!illegal)
-      return m;
-    else
-      return MOVE_NONE;
-  }
-  else if(move_is_long_castle(m)) {
+      for (s = Min(from, c1); s <= Max(from, c1); s++)
+          if(  (s != from && s != to && !pos.square_is_empty(s))
+             || pos.square_is_attacked(s, them))
+              illegal = true;
 
-    // The piece must be a king:
-    if(type_of_piece(pc) != KING)
-      return MOVE_NONE;
+      for (s = Min(to, d1); s <= Max(to, d1); s++)
+          if(s != from && s != to && !pos.square_is_empty(s))
+              illegal = true;
 
-    // The side to move must still have the right to castle kingside:
-    if(!pos.can_castle_queenside(us))
-      return MOVE_NONE;
+      if (   square_file(to) == FILE_B
+          && (   pos.piece_on(to + DELTA_W) == rook_of_color(them)
+              || pos.piece_on(to + DELTA_W) == queen_of_color(them)))
+          illegal = true;
 
-    assert(from == pos.king_square(us));
-    assert(to == pos.initial_qr_square(us));
-    assert(pos.piece_on(to) == rook_of_color(us));
-
-    Square c1 = relative_square(us, SQ_C1);
-    Square d1 = relative_square(us, SQ_D1);
-    Square s;
-    bool illegal = false;
-
-    for(s = Min(from, c1); s <= Max(from, c1); s++)
-      if((s != from && s != to && !pos.square_is_empty(s)) ||
-         pos.square_is_attacked(s, them))
-        illegal = true;
-    for(s = Min(to, d1); s <= Max(to, d1); s++)
-      if(s != from && s != to && !pos.square_is_empty(s))
-        illegal = true;
-    if(square_file(to) == FILE_B &&
-       (pos.piece_on(to + DELTA_W) == rook_of_color(them) ||
-        pos.piece_on(to + DELTA_W) == queen_of_color(them)))
-      illegal = true;
-
-    if(!illegal)
-      return m;
-    else
-      return MOVE_NONE;
+      return (!illegal ? m : MOVE_NONE);
   }
 
   // Normal moves
-  else {
 
-    // The destination square cannot be occupied by a friendly piece:
-    if(pos.color_of_piece_on(to) == us)
+  // The destination square cannot be occupied by a friendly piece
+  if (pos.color_of_piece_on(to) == us)
       return MOVE_NONE;
 
-    // Proceed according to the type of the moving piece.
-    switch(type_of_piece(pc)) {
-
-    case PAWN:
-      // Pawn moves, as usual, are somewhat messy.  
-      if(us == WHITE) {
-        // If the destination square is on the 8th rank, the move must be a
-        // promotion.
-        if(square_rank(to) == RANK_8 && !move_promotion(m))
+  // Proceed according to the type of the moving piece.
+  if (type_of_piece(pc) == PAWN)
+  {  
+      // If the destination square is on the 8/1th rank, the move must
+      // be a promotion.
+      if (   (  (square_rank(to) == RANK_8 && us == WHITE)
+              ||(square_rank(to) == RANK_1 && us != WHITE))
+           && !move_promotion(m))
           return MOVE_NONE;
-        
-        // Proceed according to the square delta between the source and
-        // destionation squares.
-        switch(to - from) {
-          
-        case DELTA_NW: case DELTA_NE:
-          // Capture.  The destination square must be occupied by an enemy piece
-          // (en passant captures was handled earlier).
-          if(pos.color_of_piece_on(to) != them)
-            return MOVE_NONE;
-          break;
 
-        case DELTA_N:
-          // Pawn push.  The destination square must be empty.
-          if(!pos.square_is_empty(to))
-            return MOVE_NONE;
+      // Proceed according to the square delta between the source and
+      // destionation squares.
+      switch (to - from)
+      {
+      case DELTA_NW:
+      case DELTA_NE:
+      case DELTA_SW:
+      case DELTA_SE:
+      // Capture. The destination square must be occupied by an enemy
+      // piece (en passant captures was handled earlier).
+          if (pos.color_of_piece_on(to) != them)
+              return MOVE_NONE;
           break;
 
-        case DELTA_NN:
-          // Double pawn push.  The destination square must be on the fourth
-          // rank, and both the destination square and the square between the
-          // source and destination squares must be empty.
-          if(square_rank(to) != RANK_4 || !pos.square_is_empty(to) ||
-             !pos.square_is_empty(from + DELTA_N))
-            return MOVE_NONE;
+      case DELTA_N:
+      case DELTA_S:
+      // Pawn push. The destination square must be empty.
+          if (!pos.square_is_empty(to))
+              return MOVE_NONE;
           break;
-          
-        default:
-          return MOVE_NONE;
-        }
-      }
-      else { // (us == BLACK)
-        // If the destination square is on the 1st rank, the move must be a
-        // promotion.
-        if(square_rank(to) == RANK_1 && !move_promotion(m))
+
+      case DELTA_NN:
+      // Double white pawn push. The destination square must be on the fourth
+      // rank, and both the destination square and the square between the
+      // source and destination squares must be empty.
+      if (   square_rank(to) != RANK_4
+          || !pos.square_is_empty(to)
+          || !pos.square_is_empty(from + DELTA_N))
           return MOVE_NONE;
-        
-        // Proceed according to the square delta between the source and
-        // destionation squares.
-        switch(to - from) {
-          
-        case DELTA_SW: case DELTA_SE:
-          // Capture.  The destination square must be occupied by an enemy piece
-          // (en passant captures was handled earlier).
-          if(pos.color_of_piece_on(to) != them)
-            return MOVE_NONE;
           break;
-          
-        case DELTA_S:
-          // Pawn push.  The destination square must be empty.
-          if(!pos.square_is_empty(to))
-            return MOVE_NONE;
-          break;
-          
-        case DELTA_SS:
-          // Double pawn push.  The destination square must be on the fifth
-          // rank, and both the destination square and the square between the
-          // source and destination squares must be empty.
-          if(square_rank(to) != RANK_5 || !pos.square_is_empty(to) ||
-             !pos.square_is_empty(from + DELTA_S))
-            return MOVE_NONE;
+
+      case DELTA_SS:
+      // Double black pawn push. The destination square must be on the fifth
+      // rank, and both the destination square and the square between the
+      // source and destination squares must be empty.
+          if (   square_rank(to) != RANK_5
+              || !pos.square_is_empty(to)
+              || !pos.square_is_empty(from + DELTA_S))
+              return MOVE_NONE;
           break;
-          
-        default:
+
+      default:
           return MOVE_NONE;
-        }
       }
       // The move is pseudo-legal.  Return it if it is legal.
-      if(pos.move_is_legal(m))
-        return m;
-      else
-        return MOVE_NONE;
-      break;
-
-    case KNIGHT:
-      if(pos.knight_attacks_square(from, to) && pos.move_is_legal(m) &&
-         !move_promotion(m))
-        return m;
-      else
-        return MOVE_NONE;
-      break;
-      
-    case BISHOP:
-      if(pos.bishop_attacks_square(from, to) && pos.move_is_legal(m) &&
-         !move_promotion(m))
-        return m;
-      else
-        return MOVE_NONE;
-      break;
-      
-    case ROOK:
-      if(pos.rook_attacks_square(from, to) && pos.move_is_legal(m) &&
-         !move_promotion(m))
-        return m;
-      else
-        return MOVE_NONE;
-      break;
-    
-    case QUEEN:
-      if(pos.queen_attacks_square(from, to) && pos.move_is_legal(m) &&
-         !move_promotion(m))
-        return m;
-      else
-        return MOVE_NONE;
-      break;
-
-    case KING:
-      if(pos.king_attacks_square(from, to) && pos.move_is_legal(m) &&
-         !move_promotion(m))
-        return m;
-      else
-        return MOVE_NONE;
-      break;
-
-    default:
-      assert(false);
-    }
+      return (pos.move_is_legal(m) ? m : MOVE_NONE);
   }
 
-  assert(false);
-  return MOVE_NONE;
+  // Luckly we can handle all the other pieces in one go
+  return (   pos.piece_attacks_square(from, to)
+          && pos.move_is_legal(m)
+          && !move_promotion(m) ? m : MOVE_NONE);
 }
 
 
 namespace {
 
   int generate_white_pawn_captures(const Position &pos, MoveStack *mlist) {
+
     Bitboard pawns = pos.pawns(WHITE);
     Bitboard enemyPieces = pos.pieces_of_color(BLACK);
-    Bitboard b1, b2;
     Square sq;
     int n = 0;
 
-    // Captures in the a1-h8 direction:
-    b1 = (pawns << 9) & ~FileABB & enemyPieces;
+    // Captures in the a1-h8 direction
+    Bitboard b1 = (pawns << 9) & ~FileABB & enemyPieces;
 
-    // Promotions:
-    b2 = b1 & Rank8BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, QUEEN);
+    // Capturing promotions
+    Bitboard b2 = b1 & Rank8BB;
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, QUEEN);
     }
 
-    // Non-promotions:
+    // Capturing non-promotions
     b2 = b1 & ~Rank8BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_move(sq - DELTA_NE, sq);
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_move(sq - DELTA_NE, sq);
     }
 
-    // Captures in the h1-a8 direction:
+    // Captures in the h1-a8 direction
     b1 = (pawns << 7) & ~FileHBB & enemyPieces;
 
-    // Promotions:
+    // Capturing promotions
     b2 = b1 & Rank8BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, QUEEN);
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, QUEEN);
     }
 
-    // Non-promotions:
+    // Capturing non-promotions
     b2 = b1 & ~Rank8BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_move(sq - DELTA_NW, sq);
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_move(sq - DELTA_NW, sq);
     }
 
-    // Non-capturing promotions:
+    // Non-capturing promotions
     b1 = (pawns << 8) & pos.empty_squares() & Rank8BB;
-    while(b1)  {
-      sq = pop_1st_bit(&b1);
-      mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, QUEEN);
-    }
-
-    // En passant captures:
-    if(pos.ep_square() != SQ_NONE) {
-      assert(square_rank(pos.ep_square()) == RANK_6);
-      b1 = pawns & pos.black_pawn_attacks(pos.ep_square());
-      assert(b1 != EmptyBoardBB);
-      while(b1) {
+    while (b1)
+    {
         sq = pop_1st_bit(&b1);
-        mlist[n++].move = make_ep_move(sq, pos.ep_square());
-      }
+        mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, QUEEN);
     }
 
+    // En passant captures
+    if (pos.ep_square() != SQ_NONE)
+    {
+        assert(square_rank(pos.ep_square()) == RANK_6);
+        b1 = pawns & pos.black_pawn_attacks(pos.ep_square());
+        assert(b1 != EmptyBoardBB);
+        while (b1)
+        {
+            sq = pop_1st_bit(&b1);
+            mlist[n++].move = make_ep_move(sq, pos.ep_square());
+        }
+    }
     return n;
   }
 
 
   int generate_black_pawn_captures(const Position &pos, MoveStack *mlist) {
+
     Bitboard pawns = pos.pawns(BLACK);
     Bitboard enemyPieces = pos.pieces_of_color(WHITE);
-    Bitboard b1, b2;
     Square sq;
     int n = 0;
 
-    // Captures in the a8-h1 direction:
-    b1 = (pawns >> 7) & ~FileABB & enemyPieces;
+    // Captures in the a8-h1 direction
+    Bitboard b1 = (pawns >> 7) & ~FileABB & enemyPieces;
 
-    // Promotions:
-    b2 = b1 & Rank1BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, QUEEN);
+    // Capturing promotions
+    Bitboard b2 = b1 & Rank1BB;
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, QUEEN);
     }
 
-    // Non-promotions:
+    // Capturing non-promotions
     b2 = b1 & ~Rank1BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_move(sq - DELTA_SE, sq);
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_move(sq - DELTA_SE, sq);
     }
 
-    // Captures in the h8-a1 direction:
+    // Captures in the h8-a1 direction
     b1 = (pawns >> 9) & ~FileHBB & enemyPieces;
 
-    // Promotions:
+    // Capturing promotions
     b2 = b1 & Rank1BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, QUEEN);
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, QUEEN);
     }
 
-    // Non-promotions:
+    // Capturing Non-promotions
     b2 = b1 & ~Rank1BB;
-    while(b2) {
-      sq = pop_1st_bit(&b2);
-      mlist[n++].move = make_move(sq - DELTA_SW, sq);
+    while (b2)
+    {
+        sq = pop_1st_bit(&b2);
+        mlist[n++].move = make_move(sq - DELTA_SW, sq);
     }
 
-    // Non-capturing promotions:
+    // Non-capturing promotions
     b1 = (pawns >> 8) & pos.empty_squares() & Rank1BB;
-    while(b1)  {
-      sq = pop_1st_bit(&b1);
-      mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, QUEEN);
-    }
-
-    // En passant captures:
-    if(pos.ep_square() != SQ_NONE) {
-      assert(square_rank(pos.ep_square()) == RANK_3);
-      b1 = pawns & pos.white_pawn_attacks(pos.ep_square());
-      assert(b1 != EmptyBoardBB);
-      while(b1) {
+    while (b1)
+    {
         sq = pop_1st_bit(&b1);
-        mlist[n++].move = make_ep_move(sq, pos.ep_square());
-      }
+        mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, QUEEN);
     }
 
+    // En passant captures
+    if (pos.ep_square() != SQ_NONE)
+    {
+        assert(square_rank(pos.ep_square()) == RANK_3);
+        b1 = pawns & pos.white_pawn_attacks(pos.ep_square());
+        assert(b1 != EmptyBoardBB);
+        while (b1)
+        {
+            sq = pop_1st_bit(&b1);
+            mlist[n++].move = make_ep_move(sq, pos.ep_square());
+        }
+    }
     return n;
   }
-    
+
 
   int generate_white_pawn_noncaptures(const Position &pos, MoveStack *mlist) {
+
     Bitboard pawns = pos.pawns(WHITE);
     Bitboard enemyPieces = pos.pieces_of_color(BLACK);
     Bitboard emptySquares = pos.empty_squares();
@@ -1089,150 +946,126 @@ namespace {
     return n;
   }
 
-  
-  int generate_knight_moves(const Position &pos, MoveStack *mlist, 
-                            Color side, Bitboard target) {
-    Square from, to;
-    Bitboard b;
-    int i, n = 0;
-
-    for(i = 0; i < pos.knight_count(side); i++) {
-      from = pos.knight_list(side, i);
-      b = pos.knight_attacks(from) & target;
-      while(b) {
-        to = pop_1st_bit(&b);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-    return n;
-  }
 
+  int generate_piece_moves(PieceType piece, const Position &pos, MoveStack *mlist, 
+                           Color side, Bitboard target) {
 
-  int generate_bishop_moves(const Position &pos, MoveStack *mlist, 
-                            Color side, Bitboard target) {
+    const Piece_attacks_fn mem_fn = piece_attacks_fn[piece];
     Square from, to;
     Bitboard b;
-    int i, n = 0;
-
-    for(i = 0; i < pos.bishop_count(side); i++) {
-      from = pos.bishop_list(side, i);
-      b = pos.bishop_attacks(from) & target;
-      while(b) {
-        to = pop_1st_bit(&b);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-    return n;
-  }
-
+    int n = 0;
 
-  int generate_rook_moves(const Position &pos, MoveStack *mlist, 
-                          Color side, Bitboard target) {
-    Square from, to;
-    Bitboard b;
-    int i, n = 0;
-
-    for(i = 0; i < pos.rook_count(side); i++) {
-      from = pos.rook_list(side, i);
-      b = pos.rook_attacks(from) & target;
-      while(b) {
-        to = pop_1st_bit(&b);
-        mlist[n++].move = make_move(from, to);
-      }
+    for (int i = 0; i < pos.piece_count(side, piece); i++)
+    {
+        from = pos.piece_list(side, piece, i);
+        b = (pos.*mem_fn)(from) & target;
+        while (b)
+        {
+            to = pop_1st_bit(&b);
+            mlist[n++].move = make_move(from, to);
+        }
     }
     return n;
   }
 
 
-  int generate_queen_moves(const Position &pos, MoveStack *mlist, 
-                           Color side, Bitboard target) {
-    Square from, to;
-    Bitboard b;
-    int i, n = 0;
-
-    for(i = 0; i < pos.queen_count(side); i++) {
-      from = pos.queen_list(side, i);
-      b = pos.queen_attacks(from) & target;
-      while(b) {
-        to = pop_1st_bit(&b);
-        mlist[n++].move = make_move(from, to);
-      }
-    }
-    return n;
-  }
-
+  int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) {
 
-  int generate_king_moves(const Position &pos, MoveStack *mlist, 
-                          Square from, Bitboard target) {
-    Square to;
-    Bitboard b;
     int n = 0;
-    
-    b = pos.king_attacks(from) & target;
-    while(b) {
-      to = pop_1st_bit(&b);
-      mlist[n++].move = make_move(from, to);
-    }
-    return n;
-  }
 
+    if (pos.can_castle(us))
+    {
+        Color them = opposite_color(us);
+        Square ksq = pos.king_square(us);        
 
-  int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) {
-    int n = 0;
+        assert(pos.piece_on(ksq) == king_of_color(us));
 
-    if(pos.can_castle(us)) {
-      Color them = opposite_color(us);
-      Square ksq = pos.king_square(us);
-      assert(pos.piece_on(ksq) == king_of_color(us));
-      
-      if(pos.can_castle_kingside(us)) {
-        Square rsq = pos.initial_kr_square(us);
-        Square g1 = relative_square(us, SQ_G1);
-        Square f1 = relative_square(us, SQ_F1);
-        Square s;
-        bool illegal = false;
+        if (pos.can_castle_kingside(us))
+        {
+            Square rsq = pos.initial_kr_square(us);
+            Square g1 = relative_square(us, SQ_G1);
+            Square f1 = relative_square(us, SQ_F1);
+            Square s;
+            bool illegal = false;
 
-        assert(pos.piece_on(rsq) == rook_of_color(us));
+            assert(pos.piece_on(rsq) == rook_of_color(us));
 
-        for(s = Min(ksq, g1); s <= Max(ksq, g1); s++)
-          if((s != ksq && s != rsq && pos.square_is_occupied(s))
-             || pos.square_is_attacked(s, them))
-            illegal = true;
-        for(s = Min(rsq, f1); s <= Max(rsq, f1); s++)
-          if(s != ksq && s != rsq && pos.square_is_occupied(s))
-            illegal = true;
+            for (s = Min(ksq, g1); s <= Max(ksq, g1); s++)
+                if (  (s != ksq && s != rsq && pos.square_is_occupied(s))
+                    || pos.square_is_attacked(s, them))
+                    illegal = true;
+
+            for (s = Min(rsq, f1); s <= Max(rsq, f1); s++)
+                if (s != ksq && s != rsq && pos.square_is_occupied(s))
+                    illegal = true;
 
-        if(!illegal)
-          mlist[n++].move = make_castle_move(ksq, rsq);
+            if (!illegal)
+                mlist[n++].move = make_castle_move(ksq, rsq);
       }
 
-      if(pos.can_castle_queenside(us)) {
-        Square rsq = pos.initial_qr_square(us);
-        Square c1 = relative_square(us, SQ_C1);
-        Square d1 = relative_square(us, SQ_D1);
-        Square s;
-        bool illegal = false;
+      if (pos.can_castle_queenside(us))
+      {
+          Square rsq = pos.initial_qr_square(us);
+          Square c1 = relative_square(us, SQ_C1);
+          Square d1 = relative_square(us, SQ_D1);
+          Square s;
+          bool illegal = false;        
 
-        assert(pos.piece_on(rsq) == rook_of_color(us));
+          assert(pos.piece_on(rsq) == rook_of_color(us));
 
-        for(s = Min(ksq, c1); s <= Max(ksq, c1); s++)
-          if((s != ksq && s != rsq && pos.square_is_occupied(s))
-             || pos.square_is_attacked(s, them))
-            illegal = true;
-        for(s = Min(rsq, d1); s <= Max(rsq, d1); s++)
-          if(s != ksq && s != rsq && pos.square_is_occupied(s))
+          for (s = Min(ksq, c1); s <= Max(ksq, c1); s++)
+              if (  (s != ksq && s != rsq && pos.square_is_occupied(s))
+                  || pos.square_is_attacked(s, them))
+                  illegal = true;
+
+          for (s = Min(rsq, d1); s <= Max(rsq, d1); s++)
+              if (s != ksq && s != rsq && pos.square_is_occupied(s))
+                  illegal = true;
+
+        if (   square_file(rsq) == FILE_B
+            && (   pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them)
+                || pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them)))
             illegal = true;
-        if(square_file(rsq) == FILE_B &&
-           (pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them) ||
-            pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them)))
-           illegal = true;
                          
-        if(!illegal)
-          mlist[n++].move = make_castle_move(ksq, rsq);
+        if (!illegal)
+            mlist[n++].move = make_castle_move(ksq, rsq);
       }
     }
+    return n;
+  }
+
+  int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target,
+                          Bitboard dc, Square ksq, MoveStack* mlist) {
+
+    const Piece_attacks_fn mem_fn = piece_attacks_fn[pce];
+    int n = 0;
+
+    // Discovered checks
+    Bitboard b = target & dc;
+    while (b)
+    {
+        Square from = pop_1st_bit(&b);
+        Bitboard bb = (pos.*mem_fn)(from) & pos.empty_squares();
+        while (bb)
+        {
+            Square to = pop_1st_bit(&bb);
+            mlist[n++].move = make_move(from, to);
+        }
+    }
 
+    // Direct checks
+    b = target & ~dc;
+    Bitboard checkSqs = (pos.*mem_fn)(ksq) & pos.empty_squares();
+    while (b)
+    {
+        Square from = pop_1st_bit(&b);
+        Bitboard bb = (pos.*mem_fn)(from) & checkSqs;
+        while (bb)
+        {
+            Square to = pop_1st_bit(&bb);
+            mlist[n++].move = make_move(from, to);
+        }
+    }
     return n;
   }
-    
 }