Fix parametrized direction in pawns generation

It worked by accident because we always called both directions,
but definition was wrong.

Functional change due to different generation order, but
perft numbers are the correct ones.

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

diff --git a/src/movegen.cpp b/src/movegen.cpp
index e0f3baa..c9255f3 100644 (file)
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -406,8 +406,8 @@ namespace {
     const Bitboard TRank7BB  = (Us == WHITE ? Rank7BB  : Rank2BB);
     const Bitboard TRank3BB  = (Us == WHITE ? Rank3BB  : Rank6BB);
     const Square   UP        = (Us == WHITE ? DELTA_N  : DELTA_S);
-    const Square   RIGHT_UP  = (Us == WHITE ? DELTA_NE : DELTA_SE);
-    const Square   LEFT_UP   = (Us == WHITE ? DELTA_NW : DELTA_SW);
+    const Square   RIGHT_UP  = (Us == WHITE ? DELTA_NE : DELTA_SW);
+    const Square   LEFT_UP   = (Us == WHITE ? DELTA_NW : DELTA_SE);
 
     Square to;
     Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares;