Introduce enum VALUE_ZERO instead of Value(0)

[stockfish] / src / endgame.cpp

diff --git a/src/endgame.cpp b/src/endgame.cpp
index 1be384410b4d4a59091528826880a3f80f668b83..913be63f1702c21eb4d76277c2cc4a6daaeb3954 100644 (file)
--- a/src/endgame.cpp
+++ b/src/endgame.cpp
@@ -115,8 +115,8 @@ void init_bitbases() {
 template<>
 Value EvaluationFunction<KXK>::apply(const Position& pos) const {
 
-  assert(pos.non_pawn_material(weakerSide) == Value(0));
-  assert(pos.piece_count(weakerSide, PAWN) == Value(0));
+  assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
+  assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
 
   Square winnerKSq = pos.king_square(strongerSide);
   Square loserKSq = pos.king_square(weakerSide);
@@ -141,8 +141,8 @@ Value EvaluationFunction<KXK>::apply(const Position& pos) const {
 template<>
 Value EvaluationFunction<KBNK>::apply(const Position& pos) const {
 
-  assert(pos.non_pawn_material(weakerSide) == Value(0));
-  assert(pos.piece_count(weakerSide, PAWN) == Value(0));
+  assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
+  assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
   assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame + BishopValueMidgame);
   assert(pos.piece_count(strongerSide, BISHOP) == 1);
   assert(pos.piece_count(strongerSide, KNIGHT) == 1);
@@ -152,7 +152,10 @@ Value EvaluationFunction<KBNK>::apply(const Position& pos) const {
   Square loserKSq = pos.king_square(weakerSide);
   Square bishopSquare = pos.piece_list(strongerSide, BISHOP, 0);
 
-  if (same_color_squares(bishopSquare, SQ_A1))
+  // 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))
   {
       winnerKSq = flop_square(winnerKSq);
       loserKSq = flop_square(loserKSq);
@@ -170,8 +173,8 @@ Value EvaluationFunction<KBNK>::apply(const Position& pos) const {
 template<>
 Value EvaluationFunction<KPK>::apply(const Position& pos) const {
 
-  assert(pos.non_pawn_material(strongerSide) == Value(0));
-  assert(pos.non_pawn_material(weakerSide) == Value(0));
+  assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
+  assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
   assert(pos.piece_count(strongerSide, PAWN) == 1);
   assert(pos.piece_count(weakerSide, PAWN) == 0);
 
@@ -364,12 +367,12 @@ Value EvaluationFunction<KBBKN>::apply(const Position& pos) const {
 /// king alone are always draw.
 template<>
 Value EvaluationFunction<KmmKm>::apply(const Position&) const {
-  return Value(0);
+  return VALUE_ZERO;
 }
 
 template<>
 Value EvaluationFunction<KNNK>::apply(const Position&) const {
-  return Value(0);
+  return VALUE_ZERO;
 }
 
 /// KBPKScalingFunction scales endgames where the stronger side has king,
@@ -622,9 +625,9 @@ ScaleFactor ScalingFunction<KRPPKRP>::apply(const Position& pos) const {
 template<>
 ScaleFactor ScalingFunction<KPsK>::apply(const Position& pos) const {
 
-  assert(pos.non_pawn_material(strongerSide) == Value(0));
+  assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
   assert(pos.piece_count(strongerSide, PAWN) >= 2);
-  assert(pos.non_pawn_material(weakerSide) == Value(0));
+  assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
   assert(pos.piece_count(weakerSide, PAWN) == 0);
 
   Square ksq = pos.king_square(weakerSide);
@@ -821,7 +824,7 @@ ScaleFactor ScalingFunction<KNPK>::apply(const Position& pos) const {
   assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame);
   assert(pos.piece_count(strongerSide, KNIGHT) == 1);
   assert(pos.piece_count(strongerSide, PAWN) == 1);
-  assert(pos.non_pawn_material(weakerSide) == Value(0));
+  assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
   assert(pos.piece_count(weakerSide, PAWN) == 0);
 
   Square pawnSq = pos.piece_list(strongerSide, PAWN, 0);
@@ -848,8 +851,8 @@ ScaleFactor ScalingFunction<KNPK>::apply(const Position& pos) const {
 template<>
 ScaleFactor ScalingFunction<KPKP>::apply(const Position& pos) const {
 
-  assert(pos.non_pawn_material(strongerSide) == Value(0));
-  assert(pos.non_pawn_material(weakerSide) == Value(0));
+  assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
+  assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
   assert(pos.piece_count(WHITE, PAWN) == 1);
   assert(pos.piece_count(BLACK, PAWN) == 1);