From 324ca87affc4959f7017e83437fb06b6e770449c Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Wed, 19 Jan 2011 13:43:07 +0100 Subject: [PATCH] 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 --- src/endgame.cpp | 19 +++++++++---------- src/position.h | 25 ++----------------------- src/square.h | 4 ++-- 3 files changed, 13 insertions(+), 35 deletions(-) diff --git a/src/endgame.cpp b/src/endgame.cpp index 0d9d3c26..348feecf 100644 --- a/src/endgame.cpp +++ b/src/endgame.cpp @@ -155,7 +155,7 @@ Value EvaluationFunction::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::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::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::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::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::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(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(blockSq1) & pos.pieces(BISHOP, weakerSide)))) return SCALE_FACTOR_ZERO; @@ -808,7 +807,7 @@ ScaleFactor ScalingFunction::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 4305759b..3da25b6f 100644 --- a/src/position.h +++ b/src/position.h @@ -17,14 +17,9 @@ along with this program. If not, see . */ - #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 5e474f0f..0e314b04 100644 --- 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) { -- 2.39.2