Pawn move generator: dispatch at compile time

[stockfish] / src / movegen.cpp

diff --git a/src/movegen.cpp b/src/movegen.cpp
index 3dfd8f6a488bd2348ec6d0486d5801f57ee99a69..da8d08c3e4611ca9cce5f645e2616189d234ac2b 100644 (file)
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -32,29 +32,15 @@
 
 namespace {
 
 
 namespace {
 

-  inline Bitboard forward_white(Bitboard b) { return b << 8; }
-  inline Bitboard forward_right_white(Bitboard b) { return b << 9; }
-  inline Bitboard forward_left_white(Bitboard b) { return b << 7; }
-
-  inline Bitboard forward_black(Bitboard b) { return b >> 8; }
-  inline Bitboard forward_right_black(Bitboard b) { return b >> 7; }
-  inline Bitboard forward_left_black(Bitboard b) { return b >> 9; }
-

   struct PawnOffsets {
 
       Bitboard Rank3BB, Rank8BB;
       Rank RANK_8;
       SquareDelta DELTA_N, DELTA_NE, DELTA_NW;
       Color us, them;
   struct PawnOffsets {
 
       Bitboard Rank3BB, Rank8BB;
       Rank RANK_8;
       SquareDelta DELTA_N, DELTA_NE, DELTA_NW;
       Color us, them;

-      typedef Bitboard (*Shift_fn)(Bitboard b);
-      Shift_fn forward, forward_left, forward_right;

   };
   };

-
-  const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK,
-                                         &forward_white, forward_left_white, forward_right_white };
-
-  const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, RANK_1, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE,
-                                         &forward_black, &forward_left_black, &forward_right_black };
+  const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK };
+  const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, RANK_1, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE };

   
   int generate_castle_moves(const Position&, MoveStack*, Color);
 
   
   int generate_castle_moves(const Position&, MoveStack*, Color);
 


@@ -648,7 +634,7 @@ namespace {
     int n = 0;
 
     // Captures in the a1-h8 (a8-h1 for black) direction
     int n = 0;
 
     // Captures in the a1-h8 (a8-h1 for black) direction

-    Bitboard b1 = (ofs.forward_right)(pawns) & ~FileABB & enemyPieces;
+    Bitboard b1 = (C == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces;

 
     // Capturing promotions
     Bitboard b2 = b1 & ofs.Rank8BB;
 
     // Capturing promotions
     Bitboard b2 = b1 & ofs.Rank8BB;


@@ -667,7 +653,7 @@ namespace {
     }
 
     // Captures in the h1-a8 (h8-a1 for black) direction
     }
 
     // Captures in the h1-a8 (h8-a1 for black) direction

-    b1 = (ofs.forward_left)(pawns) & ~FileHBB & enemyPieces;
+    b1 = (C == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces;

 
     // Capturing promotions
     b2 = b1 & ofs.Rank8BB;
 
     // Capturing promotions
     b2 = b1 & ofs.Rank8BB;


@@ -686,7 +672,7 @@ namespace {
     }
 
     // Non-capturing promotions
     }
 
     // Non-capturing promotions

-    b1 = (ofs.forward)(pawns) & pos.empty_squares() & Rank8BB;
+    b1 = (C == WHITE ? pawns << 8 : pawns >> 8) & pos.empty_squares() & Rank8BB;

     while (b1)
     {
         sq = pop_1st_bit(&b1);
     while (b1)
     {
         sq = pop_1st_bit(&b1);


@@ -725,7 +711,7 @@ namespace {
     int n = 0;
 
     // Underpromotion captures in the a1-h8 (a8-h1 for black) direction
     int n = 0;
 
     // Underpromotion captures in the a1-h8 (a8-h1 for black) direction

-    b1 = ofs.forward_right(pawns) & ~FileABB & enemyPieces & ofs.Rank8BB;
+    b1 = (C == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces & ofs.Rank8BB;

     while (b1)
     {
         sq = pop_1st_bit(&b1);
     while (b1)
     {
         sq = pop_1st_bit(&b1);


@@ -735,7 +721,7 @@ namespace {
     }
 
     // Underpromotion captures in the h1-a8 (h8-a1 for black) direction
     }
 
     // Underpromotion captures in the h1-a8 (h8-a1 for black) direction

-    b1 = ofs.forward_left(pawns) & ~FileHBB & enemyPieces & ofs.Rank8BB;
+    b1 = (C == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces & ofs.Rank8BB;

     while (b1)
     {
         sq = pop_1st_bit(&b1);
     while (b1)
     {
         sq = pop_1st_bit(&b1);


@@ -745,7 +731,7 @@ namespace {
     }
 
     // Single pawn pushes
     }
 
     // Single pawn pushes

-    b1 = ofs.forward(pawns) & emptySquares;
+    b1 = (C == WHITE ? pawns << 8 : pawns >> 8) & emptySquares;

     b2 = b1 & ofs.Rank8BB;
     while (b2)
     {
     b2 = b1 & ofs.Rank8BB;
     while (b2)
     {


@@ -762,7 +748,7 @@ namespace {
     }
 
     // Double pawn pushes
     }
 
     // Double pawn pushes

-    b2 = (ofs.forward(b1 & ofs.Rank3BB)) & emptySquares;
+    b2 = (C == WHITE ? (b1 & ofs.Rank3BB) << 8 : (b1 & ofs.Rank3BB) >> 8) & emptySquares;

     while (b2)
     {
       sq = pop_1st_bit(&b2);
     while (b2)
     {
       sq = pop_1st_bit(&b2);


@@ -772,72 +758,6 @@ namespace {
   }
 
 
   }
 
 

-  int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) {
-
-    int n = 0;
-
-    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;
-
-            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;
-
-            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;        
-
-          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))
-                  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);
-      }
-    }
-    return n;
-  }
-
-

   template<Color C>
   int generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist, int n)
   {
   template<Color C>
   int generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist, int n)
   {


@@ -852,7 +772,7 @@ namespace {
     Bitboard b1 = pos.pawns(pos.side_to_move()) & ~file_bb(ksq), b2, b3;
 
     // Discovered checks, single pawn pushes
     Bitboard b1 = pos.pawns(pos.side_to_move()) & ~file_bb(ksq), b2, b3;
 
     // Discovered checks, single pawn pushes

-    b2 = b3 = (ofs.forward)(b1 & dc) & ~ofs.Rank8BB & empty;
+    b2 = b3 = (C == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & ~ofs.Rank8BB & empty;

     while (b3)
     {
         Square to = pop_1st_bit(&b3);
     while (b3)
     {
         Square to = pop_1st_bit(&b3);


@@ -860,7 +780,7 @@ namespace {
     }
 
     // Discovered checks, double pawn pushes
     }
 
     // Discovered checks, double pawn pushes

-    b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty;
+    b3 = (C == WHITE ? (b2 & ofs.Rank3BB) << 8 : (b2 & ofs.Rank3BB) >> 8) & empty;

     while (b3)
     {
         Square to = pop_1st_bit(&b3);
     while (b3)
     {
         Square to = pop_1st_bit(&b3);


@@ -873,7 +793,7 @@ namespace {
     b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ??
 
     // Direct checks, single pawn pushes
     b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ??
 
     // Direct checks, single pawn pushes

-    b2 = (ofs.forward)(b1) & empty;
+    b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & empty;

     b3 = b2 & pos.pawn_attacks(ofs.them, ksq);
     while (b3)
     {
     b3 = b2 & pos.pawn_attacks(ofs.them, ksq);
     while (b3)
     {


@@ -882,7 +802,10 @@ namespace {
     }
 
     // Direct checks, double pawn pushes
     }
 
     // Direct checks, double pawn pushes

-    b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty & pos.pawn_attacks(ofs.them, ksq);
+    b3 =  (C == WHITE ? (b2 & ofs.Rank3BB) << 8 : (b2 & ofs.Rank3BB) >> 8)
+        & empty
+        & pos.pawn_attacks(ofs.them, ksq);
+

     while (b3)
     {
         Square to = pop_1st_bit(&b3);
     while (b3)
     {
         Square to = pop_1st_bit(&b3);


@@ -902,7 +825,7 @@ namespace {
 
     // Single pawn pushes. We don't have to AND with empty squares here,
     // because the blocking squares will always be empty.
 
     // Single pawn pushes. We don't have to AND with empty squares here,
     // because the blocking squares will always be empty.

-    Bitboard b2 = (ofs.forward)(b1) & blockSquares;
+    Bitboard b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & blockSquares;

     while (b2)
     {
         Square to = pop_1st_bit(&b2);
     while (b2)
     {
         Square to = pop_1st_bit(&b2);


@@ -920,7 +843,8 @@ namespace {
     }
 
     // Double pawn pushes
     }
 
     // Double pawn pushes

-    b2 = (ofs.forward)((ofs.forward)(b1) & pos.empty_squares() & ofs.Rank3BB) & blockSquares;
+    b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & pos.empty_squares() & ofs.Rank3BB;
+    b2 = (C == WHITE ? b2 << 8 : b2 >> 8) & blockSquares;;

     while (b2)
     {
         Square to = pop_1st_bit(&b2);
     while (b2)
     {
         Square to = pop_1st_bit(&b2);


@@ -933,4 +857,70 @@ namespace {
     }
     return n;
   }
     }
     return n;
   }

+
+
+  int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) {
+
+    int n = 0;
+
+    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;
+
+            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;
+
+            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;        
+
+          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))
+                  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);
+      }
+    }
+    return n;
+  }

 }
 }