Unify capture and promotion tests

Small code cleanup and a bit faster too.

The only functional change is that in extension
in pv node we extend promotions and not only captures
when condition met.

This is practically an undetectable change and has
no impact on strenght.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/position.h

@@ -207,6 +207,7 @@ public:
   bool move_is_check(Move m) const;
   bool move_is_check(Move m, Bitboard dcCandidates) const;
   bool move_is_capture(Move m) const;
+  bool move_is_capture_or_promotion(Move m) const;
   bool move_is_passed_pawn_push(Move m) const;
   bool move_attacks_square(Move m, Square s) const;
 
@@ -568,8 +569,13 @@ inline bool Position::has_pawn_on_7th(Color c) const {
 inline bool Position::move_is_capture(Move m) const {
 
   // Move must not be MOVE_NONE !
+  return (m & (3 << 15)) ? !move_is_castle(m) : !square_is_empty(move_to(m));
+}
 
-  return (!square_is_empty(move_to(m)) && !move_is_castle(m)) || move_is_ep(m);
+inline bool Position::move_is_capture_or_promotion(Move m) const {
+
+  // Move must not be MOVE_NONE !
+  return (m & (0x1F << 12)) ? !move_is_castle(m) : !square_is_empty(move_to(m));
 }
 
 #endif // !defined(POSITION_H_INCLUDED)

src/search.cpp

@@ -288,7 +288,6 @@ namespace {
   bool ok_to_do_nullmove(const Position& pos);
   bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d);
   bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
-  bool ok_to_history(const Position& pos, Move m);
   void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
   void update_killers(Move m, SearchStack& ss);
 
@@ -868,9 +867,9 @@ namespace {
                       << " currmovenumber " << i + 1 << std::endl;
 
         // Decide search depth for this move
-        bool moveIsCapture = pos.move_is_capture(move);
+        bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
         bool dangerous;
-        ext = extension(pos, move, true, moveIsCapture, pos.move_is_check(move), false, false, &dangerous);
+        ext = extension(pos, move, true, captureOrPromotion, pos.move_is_check(move), false, false, &dangerous);
         newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
 
         // Make the move, and search it
@@ -897,8 +896,7 @@ namespace {
             if (   newDepth >= 3*OnePly
                 && i >= MultiPV + LMRPVMoves
                 && !dangerous
-                && !moveIsCapture
+                && !captureOrPromotion
-                && !move_is_promotion(move)
                 && !move_is_castle(move))
             {
                 ss[0].reduction = OnePly;
@@ -1093,13 +1091,13 @@ namespace {
 
       bool singleReply = (isCheck && mp.number_of_evasions() == 1);
       bool moveIsCheck = pos.move_is_check(move, dcCandidates);
-      bool moveIsCapture = pos.move_is_capture(move);
+      bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;
 
       // Decide the new search depth
       bool dangerous;
-      Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
+      Depth ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
       Depth newDepth = depth - OnePly + ext;
 
       // Make and search the move
@@ -1115,8 +1113,7 @@ namespace {
         if (    depth >= 3*OnePly
             &&  moveCount >= LMRPVMoves
             && !dangerous
-            && !moveIsCapture
+            && !captureOrPromotion
-            && !move_is_promotion(move)
             && !move_is_castle(move)
             && !move_is_killer(move, ss[ply]))
         {
@@ -1200,7 +1197,7 @@ namespace {
     {
         BetaCounter.add(pos.side_to_move(), depth, threadID);
         Move m = ss[ply].pv[ply];
-        if (ok_to_history(pos, m)) // Only non capture moves are considered
+        if (!pos.move_is_capture_or_promotion(m))
         {
             update_history(pos, m, depth, movesSearched, moveCount);
             update_killers(m, ss[ply]);
@@ -1354,20 +1351,19 @@ namespace {
 
       bool singleReply = (isCheck && mp.number_of_evasions() == 1);
       bool moveIsCheck = pos.move_is_check(move, dcCandidates);
-      bool moveIsCapture = pos.move_is_capture(move);
+      bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       movesSearched[moveCount++] = ss[ply].currentMove = move;
 
       // Decide the new search depth
       bool dangerous;
-      Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
+      Depth ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
       Depth newDepth = depth - OnePly + ext;
 
       // Futility pruning
       if (    useFutilityPruning
           && !dangerous
-          && !moveIsCapture
+          && !captureOrPromotion)
-          && !move_is_promotion(move))
       {
           // History pruning. See ok_to_prune() definition
           if (   moveCount >= 2 + int(depth)
@@ -1400,8 +1396,7 @@ namespace {
       if (    depth >= 3*OnePly
           &&  moveCount >= LMRNonPVMoves
           && !dangerous
-          && !moveIsCapture
+          && !captureOrPromotion
-          && !move_is_promotion(move)
           && !move_is_castle(move)
           && !move_is_killer(move, ss[ply]))
       {
@@ -1460,7 +1455,7 @@ namespace {
     {
         BetaCounter.add(pos.side_to_move(), depth, threadID);
         Move m = ss[ply].pv[ply];
-        if (ok_to_history(pos, m)) // Only non capture moves are considered
+        if (!pos.move_is_capture_or_promotion(m))
         {
             update_history(pos, m, depth, movesSearched, moveCount);
             update_killers(m, ss[ply]);
@@ -1644,7 +1639,7 @@ namespace {
     }
 
     // Update killers only for good check moves
-    if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered
+    if (alpha >= beta && !pos.move_is_capture_or_promotion(m))
         update_killers(m, ss[ply]);
 
     return bestValue;
@@ -1679,7 +1674,7 @@ namespace {
       assert(move_is_ok(move));
 
       bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
-      bool moveIsCapture = pos.move_is_capture(move);
+      bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       lock_grab(&(sp->lock));
       int moveCount = ++sp->moves;
@@ -1689,14 +1684,13 @@ namespace {
 
       // Decide the new search depth.
       bool dangerous;
-      Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, false, false, &dangerous);
+      Depth ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
       Depth newDepth = sp->depth - OnePly + ext;
 
       // Prune?
       if (    useFutilityPruning
           && !dangerous
-          && !moveIsCapture
+          && !captureOrPromotion)
-          && !move_is_promotion(move))
       {
           // History pruning. See ok_to_prune() definition
           if (   moveCount >= 2 + int(sp->depth)
@@ -1736,8 +1730,7 @@ namespace {
       // if the move fails high will be re-searched at full depth.
       if (   !dangerous
           &&  moveCount >= LMRNonPVMoves
-          && !moveIsCapture
+          && !captureOrPromotion
-          && !move_is_promotion(move)
           && !move_is_castle(move)
           && !move_is_killer(move, ss[sp->ply]))
       {
@@ -1819,7 +1812,7 @@ namespace {
            && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
     {
       bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
-      bool moveIsCapture = pos.move_is_capture(move);
+      bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
 
       assert(move_is_ok(move));
 
@@ -1831,7 +1824,7 @@ namespace {
 
       // Decide the new search depth.
       bool dangerous;
-      Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, false, false, &dangerous);
+      Depth ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
       Depth newDepth = sp->depth - OnePly + ext;
 
       // Make and search the move.
@@ -1842,8 +1835,7 @@ namespace {
       // if the move fails high will be re-searched at full depth.
       if (   !dangerous
           &&  moveCount >= LMRPVMoves
-          && !moveIsCapture
+          && !captureOrPromotion
-          && !move_is_promotion(move)
           && !move_is_castle(move)
           && !move_is_killer(move, ss[sp->ply]))
       {
@@ -2268,8 +2260,8 @@ namespace {
   // extended, as example because the corresponding UCI option is set to zero,
   // the move is marked as 'dangerous' so, at least, we avoid to prune it.
 
-  Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check,
+  Depth extension(const Position& pos, Move m, bool pvNode, bool captureOrPromotion,
-                  bool singleReply, bool mateThreat, bool* dangerous) {
+                  bool check, bool singleReply, bool mateThreat, bool* dangerous) {
 
     assert(m != MOVE_NONE);
 
@@ -2303,7 +2295,7 @@ namespace {
         }
     }
 
-    if (   capture
+    if (   captureOrPromotion
         && pos.type_of_piece_on(move_to(m)) != PAWN
         && (  pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
             - pos.midgame_value_of_piece_on(move_to(m)) == Value(0))
@@ -2315,7 +2307,7 @@ namespace {
     }
 
     if (   pvNode
-        && capture
+        && captureOrPromotion
         && pos.type_of_piece_on(move_to(m)) != PAWN
         && pos.see_sign(m) >= 0)
     {
@@ -2349,9 +2341,8 @@ namespace {
 
     assert(move_is_ok(m));
     assert(threat == MOVE_NONE || move_is_ok(threat));
-    assert(!move_is_promotion(m));
     assert(!pos.move_is_check(m));
-    assert(!pos.move_is_capture(m));
+    assert(!pos.move_is_capture_or_promotion(m));
     assert(!pos.move_is_passed_pawn_push(m));
     assert(d >= OnePly);
 
@@ -2413,15 +2404,6 @@ namespace {
   }
 
 
-  // ok_to_history() returns true if a move m can be stored
-  // in history. Should be a non capturing move nor a promotion.
-
-  bool ok_to_history(const Position& pos, Move m) {
-
-    return !pos.move_is_capture(m) && !move_is_promotion(m);
-  }
-
-
   // update_history() registers a good move that produced a beta-cutoff
   // in history and marks as failures all the other moves of that ply.
 
@@ -2433,7 +2415,7 @@ namespace {
     for (int i = 0; i < moveCount - 1; i++)
     {
         assert(m != movesSearched[i]);
-        if (ok_to_history(pos, movesSearched[i]))
+        if (!pos.move_is_capture_or_promotion(movesSearched[i]))
             H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]));
     }
   }