Generalize shift_bb() to handle double pushes

[stockfish] / src / bitboard.h

diff --git a/src/bitboard.h b/src/bitboard.h
index e0e2fe64545ececedd4acf53852b9fd7e3b7dbf0..888e96905469b1c907340a79beaca613d2b90c41 100644 (file)
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -26,7 +26,7 @@
 namespace Bitboards {
 
 void init();
-void print(Bitboard b);
+const std::string pretty(Bitboard b);
 
 }
 
@@ -74,6 +74,7 @@ extern Bitboard AdjacentFilesBB[FILE_NB];
 extern Bitboard InFrontBB[COLOR_NB][RANK_NB];
 extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
 extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
+extern Bitboard LineBB[SQUARE_NB][SQUARE_NB];
 extern Bitboard DistanceRingsBB[SQUARE_NB][8];
 extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
 extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
@@ -129,10 +130,9 @@ inline int rank_distance(Square s1, Square s2) {
 template<Square Delta>
 inline Bitboard shift_bb(Bitboard b) {
 
-  return  Delta == DELTA_N  ?  b             << 8 : Delta == DELTA_S  ?  b             >> 8
-        : Delta == DELTA_NE ? (b & ~FileHBB) << 9 : Delta == DELTA_SE ? (b & ~FileHBB) >> 7
+  return  Delta == DELTA_NE ? (b & ~FileHBB) << 9 : Delta == DELTA_SE ? (b & ~FileHBB) >> 7
         : Delta == DELTA_NW ? (b & ~FileABB) << 7 : Delta == DELTA_SW ? (b & ~FileABB) >> 9
-        : 0;
+        : Delta > 0 ? b << Delta : b >> -Delta;
 }
 
 
@@ -176,7 +176,7 @@ inline Bitboard in_front_bb(Color c, Rank r) {
 
 /// between_bb() returns a bitboard representing all squares between two squares.
 /// For instance, between_bb(SQ_C4, SQ_F7) returns a bitboard with the bits for
-/// square d5 and e6 set.  If s1 and s2 are not on the same line, file or diagonal,
+/// square d5 and e6 set.  If s1 and s2 are not on the same rank, file or diagonal,
 /// 0 is returned.
 
 inline Bitboard between_bb(Square s1, Square s2) {
@@ -222,12 +222,11 @@ inline Bitboard squares_of_color(Square s) {
 }
 
 
-/// squares_aligned() returns true if the squares s1, s2 and s3 are aligned
+/// aligned() returns true if the squares s1, s2 and s3 are aligned
 /// either on a straight or on a diagonal line.
 
-inline bool squares_aligned(Square s1, Square s2, Square s3) {
-  return  (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3])
-        & (     SquareBB[s1] |      SquareBB[s2] |      SquareBB[s3]);
+inline bool aligned(Square s1, Square s2, Square s3) {
+  return LineBB[s1][s2] & s3;
 }
 
 
@@ -241,6 +240,9 @@ FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
   Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics;
   unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
 
+  if (HasPext)
+      return unsigned(_pext_u64(occ, Masks[s]));
+
   if (Is64Bit)
       return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);
 
@@ -254,24 +256,34 @@ inline Bitboard attacks_bb(Square s, Bitboard occ) {
   return (Pt == ROOK ? RAttacks : BAttacks)[s][magic_index<Pt>(s, occ)];
 }
 
+inline Bitboard attacks_bb(Piece pc, Square s, Bitboard occ) {
+
+  switch (type_of(pc))
+  {
+  case BISHOP: return attacks_bb<BISHOP>(s, occ);
+  case ROOK  : return attacks_bb<ROOK>(s, occ);
+  case QUEEN : return attacks_bb<BISHOP>(s, occ) | attacks_bb<ROOK>(s, occ);
+  default    : return StepAttacksBB[pc][s];
+  }
+}
 
-/// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
-/// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
+/// lsb()/msb() finds the least/most significant bit in a non-zero bitboard.
+/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard.
 
 #ifdef USE_BSFQ
 
 #  if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
 
 FORCE_INLINE Square lsb(Bitboard b) {
-  unsigned long index;
-  _BitScanForward64(&index, b);
-  return (Square) index;
+  unsigned long idx;
+  _BitScanForward64(&idx, b);
+  return (Square) idx;
 }
 
 FORCE_INLINE Square msb(Bitboard b) {
-  unsigned long index;
-  _BitScanReverse64(&index, b);
-  return (Square) index;
+  unsigned long idx;
+  _BitScanReverse64(&idx, b);
+  return (Square) idx;
 }
 
 #  elif defined(__arm__)
@@ -292,15 +304,15 @@ FORCE_INLINE Square lsb(Bitboard b) {
 #  else
 
 FORCE_INLINE Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen
-  Bitboard index;
-  __asm__("bsfq %1, %0": "=r"(index): "rm"(b) );
-  return (Square) index;
+  Bitboard idx;
+  __asm__("bsfq %1, %0": "=r"(idx): "rm"(b) );
+  return (Square) idx;
 }
 
 FORCE_INLINE Square msb(Bitboard b) {
-  Bitboard index;
-  __asm__("bsrq %1, %0": "=r"(index): "rm"(b) );
-  return (Square) index;
+  Bitboard idx;
+  __asm__("bsrq %1, %0": "=r"(idx): "rm"(b) );
+  return (Square) idx;
 }
 
 #  endif
@@ -319,9 +331,10 @@ extern Square pop_lsb(Bitboard* b);
 
 #endif
 
-/// lsb() overload finds least significant bit relative to the given color
-inline Square lsb(Color c, Bitboard b) {
-  return c == WHITE ? lsb(b) : msb(b);
-}
+/// frontmost_sq() and backmost_sq() find the square corresponding to the
+/// most/least advanced bit relative to the given color.
+
+inline Square frontmost_sq(Color c, Bitboard b) { return c == WHITE ? msb(b) : lsb(b); }
+inline Square  backmost_sq(Color c, Bitboard b) { return c == WHITE ? lsb(b) : msb(b); }
 
 #endif // #ifndef BITBOARD_H_INCLUDED