// 'dangerous' moves so that we avoid to prune it.
FORCE_INLINE bool is_dangerous(const Position& pos, Move m, bool captureOrPromotion) {
- // Test for a pawn pushed to 7th or a passed pawn move
- if (type_of(pos.piece_moved(m)) == PAWN)
- {
- Color c = pos.side_to_move();
- if ( relative_rank(c, to_sq(m)) == RANK_7
- || pos.pawn_is_passed(c, to_sq(m)))
- return true;
- }
+ // Test for a passed pawn move
+ if ( type_of(pos.piece_moved(m)) == PAWN
+ && pos.pawn_is_passed(pos.side_to_move(), to_sq(m)))
+ return true;
// Test for a capture that triggers a pawn endgame
if ( captureOrPromotion
ss->currentMove = MOVE_NULL;
// Null move dynamic reduction based on depth
- int R = 3 + (depth >= 5 * ONE_PLY ? depth / 8 : 0);
+ Depth R = 3 * ONE_PLY + depth / 4;
// Null move dynamic reduction based on value
if (refinedValue - PawnValueMidgame > beta)
- R++;
+ R += ONE_PLY;
pos.do_null_move<true>(st);
(ss+1)->skipNullMove = true;
- nullValue = depth-R*ONE_PLY < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
- : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY);
+ nullValue = depth-R < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R);
(ss+1)->skipNullMove = false;
pos.do_null_move<false>(st);
// Do verification search at high depths
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, alpha, beta, depth-R*ONE_PLY);
+ Value v = search<NonPV>(pos, ss, alpha, beta, depth-R);
ss->skipNullMove = false;
if (v >= beta)
if ( singularExtensionNode
&& !ext
&& move == ttMove
- && pos.pl_move_is_legal(move, ci.pinned))
+ && pos.pl_move_is_legal(move, ci.pinned)
+ && abs(ttValue) < VALUE_KNOWN_WIN)
{
- if (abs(ttValue) < VALUE_KNOWN_WIN)
- {
- Value rBeta = ttValue - int(depth);
- ss->excludedMove = move;
- ss->skipNullMove = true;
- value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
- ss->skipNullMove = false;
- ss->excludedMove = MOVE_NONE;
- if (value < rBeta)
- ext = ONE_PLY;
- }
+ Value rBeta = ttValue - int(depth);
+ ss->excludedMove = move;
+ ss->skipNullMove = true;
+ value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
+ ss->skipNullMove = false;
+ ss->excludedMove = MOVE_NONE;
+
+ if (value < rBeta)
+ ext = ONE_PLY;
}
// Update current move (this must be done after singular extension search)
while (b)
{
// Note that here we generate illegal "double move"!
- if (futilityBase + PieceValueEndgame[pos.piece_on(pop_1st_bit(&b))] >= beta)
+ if (futilityBase + PieceValueEndgame[pos.piece_on(pop_lsb(&b))] >= beta)
return true;
}