Add popcnt-support in Makefile

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index be4e234d99d9b937036ee9d6fabb9cec170a0e40..10c9d6796311fd5bf061d6d1bbac4b15686a56c5 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -458,13 +458,6 @@ void Position::find_checkers() {
 
 /// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal
 
-bool Position::pl_move_is_legal(Move m) const {
-
-  // If we're in check, all pseudo-legal moves are legal, because our
-  // check evasion generator only generates true legal moves.
-  return is_check() || pl_move_is_legal(m, pinned_pieces(side_to_move()));
-}
-
 bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
 
   assert(is_ok());
@@ -518,6 +511,32 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
 }
 
 
+/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion
+
+bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const
+{
+  assert(is_check());
+
+  Color us = side_to_move();
+  Square from = move_from(m);
+  Square to = move_to(m);
+
+  // King moves and en-passant captures are verified in pl_move_is_legal()
+  if (type_of_piece_on(from) == KING || move_is_ep(m))
+      return pl_move_is_legal(m, pinned);
+
+  Bitboard target = checkers();
+  Square checksq = pop_1st_bit(&target);
+
+  if (target) // double check ?
+      return false;
+
+  // Our move must be a blocking evasion or a capture of the checking piece
+  target = squares_between(checksq, king_square(us)) | checkers();
+  return bit_is_set(target, to) && pl_move_is_legal(m, pinned);
+}
+
+
 /// Position::move_is_check() tests whether a pseudo-legal move is a check
 
 bool Position::move_is_check(Move m) const {
@@ -1337,7 +1356,6 @@ int Position::see(Square from, Square to) const {
 
   Bitboard attackers, stmAttackers, b;
 
-  assert(!shortcut || from != SQ_NONE);
   assert(square_is_ok(from) || from == SQ_NONE);
   assert(square_is_ok(to));
 
@@ -1726,11 +1744,10 @@ bool Position::has_mate_threat(Color c) {
 
   MoveStack mlist[120];
   bool result = false;
-  Bitboard dc = discovered_check_candidates(sideToMove);
   Bitboard pinned = pinned_pieces(sideToMove);
 
   // Generate pseudo-legal non-capture and capture check moves
-  MoveStack* last = generate_non_capture_checks(*this, mlist, dc);
+  MoveStack* last = generate_non_capture_checks(*this, mlist);
   last = generate_captures(*this, last);
 
   // Loop through the moves, and see if one of them is mate