X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovegen.cpp;h=ff8f6c6e16f6f2f186e27dad9972f43b8cf9bb1f;hb=2a461b4b745b2542f6e13bab8c60abdb366bc128;hp=14705d30df86c733a0519169bae8fb171777bfb9;hpb=be4ee0729ddc7eddcbb7912143a75769ea20fcd1;p=stockfish

diff --git a/src/movegen.cpp b/src/movegen.cpp
index 14705d30..ff8f6c6e 100644
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -24,6 +24,7 @@
 
 #include <cassert>
 
+#include "bitcount.h"
 #include "movegen.h"
 
 // Simple macro to wrap a very common while loop, no facny, no flexibility,
@@ -131,7 +132,7 @@ namespace {
 
 
 /// generate_captures generates() all pseudo-legal captures and queen
-/// promotions.  The return value is the number of moves generated.
+/// promotions. The return value is the number of moves generated.
 
 int generate_captures(const Position& pos, MoveStack* mlist) {
 
@@ -392,7 +393,6 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   assert(pinned == pos.pinned_pieces(pos.side_to_move()));
 
   Color us = pos.side_to_move();
-  Color them = opposite_color(us);
   Square from = move_from(m);
   Piece pc = pos.piece_on(from);
 
@@ -401,6 +401,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   if (color_of_piece(pc) != us)
       return false;
 
+  Color them = opposite_color(us);
   Square to = move_to(m);
 
   // En passant moves
@@ -505,7 +506,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
       // be a promotion.
       if (   (  (square_rank(to) == RANK_8 && us == WHITE)
               ||(square_rank(to) == RANK_1 && us != WHITE))
-           && !move_promotion(m))
+           && !move_is_promotion(m))
           return false;
 
       // Proceed according to the square delta between the source and
@@ -559,7 +560,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   // Luckly we can handle all the other pieces in one go
   return (   pos.piece_attacks_square(pos.piece_on(from), from, to)
           && pos.pl_move_is_legal(m, pinned)
-          && !move_promotion(m));
+          && !move_is_promotion(m));
 }
 
 
@@ -756,13 +757,15 @@ namespace {
     const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
     const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
     const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
+    const SquareDelta TDELTA_S = (Us == WHITE ? DELTA_S : DELTA_N);
 
     Bitboard b1, b2, b3;
-    Bitboard empty = pos.empty_squares();
     Bitboard pawns = pos.pawns(Us);
 
     if (dc & pawns)
     {
+         Bitboard empty = pos.empty_squares();
+
         // Pawn moves which gives 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.
@@ -786,10 +789,17 @@ namespace {
     }
 
     // Direct checks. These are possible only for pawns on neighboring files
-    // of the enemy king.
+    // and in the two ranks that, after the push, are in front of the enemy king.
     b1 = pawns & neighboring_files_bb(ksq) & ~dc;
 
+    // We can get false positives if (ksq + x) is not in [0,63] range but
+    // is not a problem, they will be filtered out later.
+    b2 = b1 & (rank_bb(ksq + 2 * TDELTA_S) | rank_bb(ksq + 3 * TDELTA_S));
+    if (!b2)
+        return mlist;
+
     // Direct checks, single pawn pushes
+    Bitboard empty = pos.empty_squares();
     b2 = move_pawns<Us, DELTA_N>(b1) & empty;
     b3 = b2 & pos.pawn_attacks(Them, ksq);
     while (b3)
@@ -828,23 +838,23 @@ namespace {
 
     // Direct checks
     b = target & ~dc;
-    if (Piece == KING || !b)
-        return mlist;
-
-    Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
-    if (!checkSqs)
-        return mlist;
-
-    while (b)
+    if (Piece != KING || b)
     {
-        Square from = pop_1st_bit(&b);
-        if (   (Piece == QUEEN  && !(QueenPseudoAttacks[from]  & checkSqs))
-            || (Piece == ROOK   && !(RookPseudoAttacks[from]   & checkSqs))
-            || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
-            continue;
+        Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
+        if (!checkSqs)
+            return mlist;
 
-        Bitboard bb = pos.piece_attacks<Piece>(from) & checkSqs;
-        SERIALIZE_MOVES(bb);
+        while (b)
+        {
+            Square from = pop_1st_bit(&b);
+            if (   (Piece == QUEEN  && !(QueenPseudoAttacks[from]  & checkSqs))
+                || (Piece == ROOK   && !(RookPseudoAttacks[from]   & checkSqs))
+                || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
+                continue;
+
+            Bitboard bb = pos.piece_attacks<Piece>(from) & checkSqs;
+            SERIALIZE_MOVES(bb);
+        }
     }
     return mlist;
   }
@@ -854,7 +864,7 @@ namespace {
                                              Bitboard blockSquares, MoveStack* mlist) {
 
     // Calculate our parametrized parameters at compile time
-    const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
+    const Rank TRANK_8 = (Us == WHITE ? RANK_8 : RANK_1);
     const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
     const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
 
@@ -872,7 +882,7 @@ namespace {
 
         assert(pos.piece_on(to) == EMPTY);
 
-        if (square_rank(to) == TRank8BB)
+        if (square_rank(to) == TRANK_8)
         {
             (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN);
             (*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK);