Consolidate Square Flipping

protonspring · vondele · commit 960d59d54143 · 2020-03-04T07:11:48.000+01:00
Add a flip_rank() and flip_file() so that all of the square flipping can be consolidated. STC LLR: 2.94 (-2.94,2.94) {-1.50,0.50} Total: 57234 W: 11064 L: 10969 D: 35201 Ptnml(0-2): 822, 6562, 13801, 6563, 869 http://tests.stockfishchess.org/tests/view/5e5d2f2aafe6254521f2ffaa closes #2568 No functional change.
diff --git a/src/endgame.cpp b/src/endgame.cpp
@@ -74,9 +74,9 @@ namespace {
     assert(pos.count<PAWN>(strongSide) == 1);
 
     if (file_of(pos.square<PAWN>(strongSide)) >= FILE_E)
-        sq = Square(int(sq) ^ 7); // Mirror SQ_H1 -> SQ_A1
+        sq = flip_file(sq);
 
-    return strongSide == WHITE ? sq : ~sq;
+    return strongSide == WHITE ? sq : flip_rank(sq);
   }
 
 } // namespace
diff --git a/src/psqt.cpp b/src/psqt.cpp
@@ -114,7 +114,7 @@ void init() {
           File f = map_to_queenside(file_of(s));
           psq[ pc][ s] = score + (type_of(pc) == PAWN ? PBonus[rank_of(s)][file_of(s)]
                                                       : Bonus[pc][rank_of(s)][f]);
-          psq[~pc][~s] = -psq[pc][s];
+          psq[~pc][flip_rank(s)] = -psq[pc][s];
       }
   }
 }
diff --git a/src/syzygy/tbprobe.cpp b/src/syzygy/tbprobe.cpp
@@ -66,7 +66,6 @@ enum TBType { KEY, WDL, DTZ }; // Used as template parameter
 enum TBFlag { STM = 1, Mapped = 2, WinPlies = 4, LossPlies = 8, Wide = 16, SingleValue = 128 };
 
 inline WDLScore operator-(WDLScore d) { return WDLScore(-int(d)); }
-inline Square operator^=(Square& s, int i) { return s = Square(int(s) ^ i); }
 inline Square operator^(Square s, int i) { return Square(int(s) ^ i); }
 
 const std::string PieceToChar = " PNBRQK  pnbrqk";
@@ -743,7 +742,7 @@ Ret do_probe_table(const Position& pos, T* entry, WDLScore wdl, ProbeState* resu
     // the triangle A1-D1-D4.
     if (file_of(squares[0]) > FILE_D)
         for (int i = 0; i < size; ++i)
-            squares[i] ^= 7; // Horizontal flip: SQ_H1 -> SQ_A1
+            squares[i] = flip_file(squares[i]);
 
     // Encode leading pawns starting with the one with minimum MapPawns[] and
     // proceeding in ascending order.
@@ -762,7 +761,7 @@ Ret do_probe_table(const Position& pos, T* entry, WDLScore wdl, ProbeState* resu
     // piece is below RANK_5.
     if (rank_of(squares[0]) > RANK_4)
         for (int i = 0; i < size; ++i)
-            squares[i] ^= SQ_A8; // Vertical flip: SQ_A8 -> SQ_A1
+            squares[i] = flip_rank(squares[i]);
 
     // Look for the first piece of the leading group not on the A1-D4 diagonal
     // and ensure it is mapped below the diagonal.
@@ -1344,7 +1343,7 @@ void Tablebases::init(const std::string& paths) {
                 if (leadPawnsCnt == 1)
                 {
                     MapPawns[sq] = availableSquares--;
-                    MapPawns[sq ^ 7] = availableSquares--; // Horizontal flip
+                    MapPawns[flip_file(sq)] = availableSquares--;
                 }
                 LeadPawnIdx[leadPawnsCnt][sq] = idx;
                 idx += Binomial[leadPawnsCnt - 1][MapPawns[sq]];
diff --git a/src/types.h b/src/types.h
@@ -358,8 +358,12 @@ constexpr Color operator~(Color c) {
   return Color(c ^ BLACK); // Toggle color
 }
 
-constexpr Square operator~(Square s) {
-  return Square(s ^ SQ_A8); // Vertical flip SQ_A1 -> SQ_A8
+constexpr Square flip_rank(Square s) {
+  return Square(s ^ SQ_A8);
+}
+
+constexpr Square flip_file(Square s) {
+  return Square(s ^ SQ_H1);
 }
 
 constexpr Piece operator~(Piece pc) {

Original file line number	Diff line number	Diff line change
`@@ -74,9 +74,9 @@ namespace {`
`74`	`74`	`assert(pos.count<PAWN>(strongSide) == 1);`
`75`	`75`
`76`	`76`	`if (file_of(pos.square<PAWN>(strongSide)) >= FILE_E)`
`77`		`- sq = Square(int(sq) ^ 7); // Mirror SQ_H1 -> SQ_A1`
	`77`	`+ sq = flip_file(sq);`
`78`	`78`
`79`		`- return strongSide == WHITE ? sq : ~sq;`
	`79`	`+ return strongSide == WHITE ? sq : flip_rank(sq);`
`80`	`80`	`}`
`81`	`81`
`82`	`82`	`} // namespace`
Original file line number	Diff line number	Diff line change
`@@ -114,7 +114,7 @@ void init() {`
`114`	`114`	`File f = map_to_queenside(file_of(s));`
`115`	`115`	`psq[ pc][ s] = score + (type_of(pc) == PAWN ? PBonus[rank_of(s)][file_of(s)]`
`116`	`116`	`: Bonus[pc][rank_of(s)][f]);`
`117`		`- psq[~pc][~s] = -psq[pc][s];`
	`117`	`+ psq[~pc][flip_rank(s)] = -psq[pc][s];`
`118`	`118`	`}`
`119`	`119`	`}`
`120`	`120`	`}`
Original file line number	Diff line number	Diff line change
`@@ -358,8 +358,12 @@ constexpr Color operator~(Color c) {`
`358`	`358`	`return Color(c ^ BLACK); // Toggle color`
`359`	`359`	`}`
`360`	`360`
`361`		`-constexpr Square operator~(Square s) {`
`362`		`- return Square(s ^ SQ_A8); // Vertical flip SQ_A1 -> SQ_A8`
	`361`	`+constexpr Square flip_rank(Square s) {`
	`362`	`+ return Square(s ^ SQ_A8);`
	`363`	`+}`
	`364`	`+`
	`365`	`+constexpr Square flip_file(Square s) {`
	`366`	`+ return Square(s ^ SQ_H1);`
`363`	`367`	`}`
`364`	`368`
`365`	`369`	`constexpr Piece operator~(Piece pc) {`