Use opposite_color_squares() instead of same_color_squares()

It is almost alwasy the requested test and is a bit faster too.

No functional change.

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

diff --git a/src/endgame.cpp b/src/endgame.cpp
index 0d9d3c26c216b2fbeb394b5a887c21530ac90425..348feecf70bf5e170211460a23145a55749610dd 100644 (file)
--- a/src/endgame.cpp
+++ b/src/endgame.cpp
@@ -155,7 +155,7 @@ Value EvaluationFunction<KBNK>::apply(const Position& pos) const {
   // kbnk_mate_table() tries to drive toward corners A1 or H8,
   // if we have a bishop that cannot reach the above squares we
   // mirror the kings so to drive enemy toward corners A8 or H1.
-  if (!same_color_squares(bishopSquare, SQ_A1))
+  if (opposite_color_squares(bishopSquare, SQ_A1))
   {
       winnerKSq = flop_square(winnerKSq);
       loserKSq = flop_square(loserKSq);
@@ -401,7 +401,7 @@ ScaleFactor ScalingFunction<KBPsK>::apply(const Position& pos) const {
       Square queeningSq = relative_square(strongerSide, make_square(pawnFile, RANK_8));
       Square kingSq = pos.king_square(weakerSide);
 
-      if (  !same_color_squares(queeningSq, bishopSq)
+      if (   opposite_color_squares(queeningSq, bishopSq)
           && file_distance(square_file(kingSq), pawnFile) <= 1)
       {
           // The bishop has the wrong color, and the defending king is on the
@@ -678,12 +678,12 @@ ScaleFactor ScalingFunction<KBPKB>::apply(const Position& pos) const {
   // Case 1: Defending king blocks the pawn, and cannot be driven away
   if (   square_file(weakerKingSq) == square_file(pawnSq)
       && relative_rank(strongerSide, pawnSq) < relative_rank(strongerSide, weakerKingSq)
-      && (  !same_color_squares(weakerKingSq, strongerBishopSq)
+      && (   opposite_color_squares(weakerKingSq, strongerBishopSq)
           || relative_rank(strongerSide, weakerKingSq) <= RANK_6))
       return SCALE_FACTOR_ZERO;
 
   // Case 2: Opposite colored bishops
-  if (!same_color_squares(strongerBishopSq, weakerBishopSq))
+  if (opposite_color_squares(strongerBishopSq, weakerBishopSq))
   {
       // We assume that the position is drawn in the following three situations:
       //
@@ -728,8 +728,7 @@ ScaleFactor ScalingFunction<KBPPKB>::apply(const Position& pos) const {
   Square wbsq = pos.piece_list(strongerSide, BISHOP, 0);
   Square bbsq = pos.piece_list(weakerSide, BISHOP, 0);
 
-  if (same_color_squares(wbsq, bbsq))
-      // Not opposite-colored bishops, no scaling
+  if (!opposite_color_squares(wbsq, bbsq))
       return SCALE_FACTOR_NONE;
 
   Square ksq = pos.king_square(weakerSide);
@@ -757,7 +756,7 @@ ScaleFactor ScalingFunction<KBPPKB>::apply(const Position& pos) const {
     // some square in the frontmost pawn's path.
     if (   square_file(ksq) == square_file(blockSq1)
         && relative_rank(strongerSide, ksq) >= relative_rank(strongerSide, blockSq1)
-        && !same_color_squares(ksq, wbsq))
+        && opposite_color_squares(ksq, wbsq))
         return SCALE_FACTOR_ZERO;
     else
         return SCALE_FACTOR_NONE;
@@ -767,14 +766,14 @@ ScaleFactor ScalingFunction<KBPPKB>::apply(const Position& pos) const {
     // in front of the frontmost pawn's path, and the square diagonally behind
     // this square on the file of the other pawn.
     if (   ksq == blockSq1
-        && !same_color_squares(ksq, wbsq)
+        && opposite_color_squares(ksq, wbsq)
         && (   bbsq == blockSq2
             || (pos.attacks_from<BISHOP>(blockSq2) & pos.pieces(BISHOP, weakerSide))
             || rank_distance(r1, r2) >= 2))
         return SCALE_FACTOR_ZERO;
 
     else if (   ksq == blockSq2
-             && !same_color_squares(ksq, wbsq)
+             && opposite_color_squares(ksq, wbsq)
              && (   bbsq == blockSq1
                  || (pos.attacks_from<BISHOP>(blockSq1) & pos.pieces(BISHOP, weakerSide))))
         return SCALE_FACTOR_ZERO;
@@ -808,7 +807,7 @@ ScaleFactor ScalingFunction<KBPKN>::apply(const Position& pos) const {
 
   if (   square_file(weakerKingSq) == square_file(pawnSq)
       && relative_rank(strongerSide, pawnSq) < relative_rank(strongerSide, weakerKingSq)
-      && (  !same_color_squares(weakerKingSq, strongerBishopSq)
+      && (   opposite_color_squares(weakerKingSq, strongerBishopSq)
           || relative_rank(strongerSide, weakerKingSq) <= RANK_6))
       return SCALE_FACTOR_ZERO;
 

diff --git a/src/position.h b/src/position.h
index 4305759b0cf751c7cfa0f1eaaea3d90fffade9fa..3da25b6f57e4c6e54b8e62af18c84e9717d385ee 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -17,14 +17,9 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-
 #if !defined(POSITION_H_INCLUDED)
 #define POSITION_H_INCLUDED
 
-////
-//// Includes
-////
-
 #include "bitboard.h"
 #include "color.h"
 #include "move.h"
@@ -32,21 +27,11 @@
 #include "square.h"
 #include "value.h"
 
-
-////
-//// Constants
-////
-
 /// Maximum number of plies per game (220 should be enough, because the
 /// maximum search depth is 100, and during position setup we reset the
 /// move counter for every non-reversible move).
 const int MaxGameLength = 220;
 
-
-////
-//// Types
-////
-
 class Position;
 
 /// struct checkInfo is initialized at c'tor time and keeps
@@ -339,11 +324,6 @@ private:
   static const Value PieceValueEndgame[17];
 };
 
-
-////
-//// Inline functions
-////
-
 inline int64_t Position::nodes_searched() const {
   return nodes;
 }
@@ -538,9 +518,8 @@ inline int Position::startpos_ply_counter() const {
 
 inline bool Position::opposite_colored_bishops() const {
 
-  return   piece_count(WHITE, BISHOP) == 1
-        && piece_count(BLACK, BISHOP) == 1
-        && !same_color_squares(piece_list(WHITE, BISHOP, 0), piece_list(BLACK, BISHOP, 0));
+  return   piece_count(WHITE, BISHOP) == 1 && piece_count(BLACK, BISHOP) == 1
+        && opposite_color_squares(piece_list(WHITE, BISHOP, 0), piece_list(BLACK, BISHOP, 0));
 }
 
 inline bool Position::has_pawn_on_7th(Color c) const {

diff --git a/src/square.h b/src/square.h
index 5e474f0f4a7574b0a04e3484664f0168ac463abf..0e314b04ac809f017d42d162a8d381caad9b8d99 100644 (file)
--- a/src/square.h
+++ b/src/square.h
@@ -107,9 +107,9 @@ inline SquareColor square_color(Square s) {
   return SquareColor((int(square_file(s)) + int(square_rank(s))) & 1);
 }
 
-inline bool same_color_squares(Square s1, Square s2) {
+inline bool opposite_color_squares(Square s1, Square s2) {
   int s = int(s1) ^ int(s2);
-  return (((s >> 3) ^ s) & 1) == 0;
+  return ((s >> 3) ^ s) & 1;
 }
 
 inline int file_distance(File f1, File f2) {