From: Marco Costalba <mcostalba@gmail.com>
Date: Mon, 30 Mar 2009 10:07:45 +0000 (+0200)
Subject: Silence idiotic warning on two's complement of an unsigned
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=d7ef09727acc11c91b4a25b775c7f6d0bf1d37d8

Silence idiotic warning on two's complement of an unsigned

MSVC gives:

warning C4146: unary minus operator applied to unsigned type,
               result still unsigned

When finds -b where b is an unsigned integer. So rewrite the two's
complement in a way to avoid the warning. Theoretically the new
version is slower, but in practice changes nothing.

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

diff --git a/src/position.cpp b/src/position.cpp
index 1081e1da..cdbd9f0d 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1618,7 +1618,7 @@ int Position::see(Square from, Square to) const {
       // Remove the attacker we just found from the 'attackers' bitboard,
       // and scan for new X-ray attacks behind the attacker.
       b = attackers & pieces_of_color_and_type(c, pt);
-      occ ^= (b & -b);
+      occ ^= (b & (~b + 1));
       attackers |=  (rook_attacks_bb(to, occ) & rooks_and_queens())
                   | (bishop_attacks_bb(to, occ) & bishops_and_queens());