X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmove.h;h=e9f7242696c9abf0fa477758b192c47f4ace9dcb;hp=65fcc250160518bf4e56f98ba4790a749208dab1;hb=72c7595f8ac72c7831ee319b8b0bc46404c5fc27;hpb=bb751d6c890f5c50c642366d601740366cfae8d0

diff --git a/src/move.h b/src/move.h
index 65fcc250..e9f72426 100644
--- a/src/move.h
+++ b/src/move.h
@@ -1,17 +1,18 @@
 /*
-  Glaurung, a UCI chess playing engine.
-  Copyright (C) 2004-2008 Tord Romstad
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+  Copyright (C) 2008 Marco Costalba
 
-  Glaurung is free software: you can redistribute it and/or modify
+  Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
-  
-  Glaurung is distributed in the hope that it will be useful,
+
+  Stockfish is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
-  
+
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
@@ -37,10 +38,22 @@
 
 class Position;
 
+/// A move needs 17 bits to be stored
+///
+/// bit  0- 5: destination square (from 0 to 63)
+/// bit  6-11: origin square (from 0 to 63)
+/// bit 12-14: promotion piece type
+/// bit    15: en passant flag
+/// bit    16: castle flag
+///
+/// Special cases are MOVE_NONE and MOVE_NULL. We can sneak these in
+/// because in any normal move destination square is always different
+/// from origin square while MOVE_NONE and MOVE_NULL have the same
+/// origin and destination square, 0 and 1 respectively.
+
 enum Move {
   MOVE_NONE = 0,
-  MOVE_NULL = 65, 
-  MOVE_MAX = 0xFFFFFF
+  MOVE_NULL = 65
 };
 
 
@@ -55,11 +68,11 @@ struct MoveStack {
 ////
 
 inline Square move_from(Move m) {
-  return Square((int(m) >> 6) & 077);
+  return Square((int(m) >> 6) & 0x3F);
 }
 
 inline Square move_to(Move m) {
-  return Square(m & 077);
+  return Square(m & 0x3F);
 }
 
 inline PieceType move_promotion(Move m) {