X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovegen.cpp;h=287b1c0dd6d98e54b0aa227d4d5b6b8a915b7436;hb=5c81602d14539f8259a715477315e28b5de7cb54;hp=dff9e8c3b4624056f0642b29e152ffac3e9e12eb;hpb=24485c96ec7dcb743c1dac8cf0cccc96456893d9;p=stockfish

diff --git a/src/movegen.cpp b/src/movegen.cpp
index dff9e8c3..287b1c0d 100644
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -1,6 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008 Marco Costalba
+  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+  Copyright (C) 2008-2009 Marco Costalba
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -176,10 +177,10 @@ int generate_noncaptures(const Position& pos, MoveStack* mlist) {
 }
 
 
-/// generate_checks() generates all pseudo-legal non-capturing, non-promoting
-/// checks. It returns the number of generated moves.
+/// generate_non_capture_checks() generates all pseudo-legal non-capturing,
+/// non-promoting checks. It returns the number of generated moves.
 
-int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
+int generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
 
   assert(pos.is_ok());
   assert(!pos.is_check());
@@ -496,6 +497,11 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   // Proceed according to the type of the moving piece.
   if (type_of_piece(pc) == PAWN)
   {
+      // Move direction must be compatible with pawn color
+      int direction = to - from;
+      if ((us == WHITE) != (direction > 0))
+          return false;
+
       // If the destination square is on the 8/1th rank, the move must
       // be a promotion.
       if (   (  (square_rank(to) == RANK_8 && us == WHITE)
@@ -505,7 +511,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
 
       // Proceed according to the square delta between the source and
       // destionation squares.
-      switch (to - from)
+      switch (direction)
       {
       case DELTA_NW:
       case DELTA_NE: