small cleanups

[stockfish] / src / movegen.cpp

diff --git a/src/movegen.cpp b/src/movegen.cpp
index 7e8961ae3b60603e35698c44277c2a6ed72656c6..5787d1743cf27eed0e4b9f0c815ad74e2a638725 100644 (file)
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -52,7 +52,7 @@ namespace {
   template<Color Us, GenType Type>
   ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target) {
 
-    constexpr Color     Them     = (Us == WHITE ? BLACK      : WHITE);
+    constexpr Color     Them     = ~Us;
     constexpr Bitboard  TRank7BB = (Us == WHITE ? Rank7BB    : Rank2BB);
     constexpr Bitboard  TRank3BB = (Us == WHITE ? Rank3BB    : Rank6BB);
     constexpr Direction Up       = pawn_push(Us);
@@ -213,11 +213,31 @@ namespace {
 
 
   template<Color Us, GenType Type>
-  ExtMove* generate_all(const Position& pos, ExtMove* moveList, Bitboard target) {
-
-    constexpr CastlingRights OO  = Us & KING_SIDE;
-    constexpr CastlingRights OOO = Us & QUEEN_SIDE;
+  ExtMove* generate_all(const Position& pos, ExtMove* moveList) {
     constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantations
+    Bitboard target;
+
+    switch (Type)
+    {
+        case CAPTURES:
+            target =  pos.pieces(~Us);
+            break;
+        case QUIETS:
+        case QUIET_CHECKS:
+            target = ~pos.pieces();
+            break;
+        case EVASIONS:
+        {
+            Square checksq = lsb(pos.checkers());
+            target = between_bb(pos.square<KING>(Us), checksq) | checksq;
+            break;
+        }
+        case NON_EVASIONS:
+            target = ~pos.pieces(Us);
+            break;
+        default:
+            static_assert(true, "Unsupported type in generate_all()");
+    }
 
     moveList = generate_pawn_moves<Us, Type>(pos, moveList, target);
     moveList = generate_moves<KNIGHT, Checks>(pos, moveList, Us, target);
@@ -232,14 +252,10 @@ namespace {
         while (b)
             *moveList++ = make_move(ksq, pop_lsb(&b));
 
-        if (Type != CAPTURES && pos.can_castle(CastlingRights(OO | OOO)))
-        {
-            if (!pos.castling_impeded(OO) && pos.can_castle(OO))
-                *moveList++ = make<CASTLING>(ksq, pos.castling_rook_square(OO));
-
-            if (!pos.castling_impeded(OOO) && pos.can_castle(OOO))
-                *moveList++ = make<CASTLING>(ksq, pos.castling_rook_square(OOO));
-        }
+        if ((Type != CAPTURES) && pos.can_castle(Us & ANY_CASTLING))
+            for(CastlingRights cr : { Us & KING_SIDE, Us & QUEEN_SIDE } )
+                if (!pos.castling_impeded(cr) && pos.can_castle(cr))
+                    *moveList++ = make<CASTLING>(ksq, pos.castling_rook_square(cr));
     }
 
     return moveList;
@@ -262,12 +278,8 @@ ExtMove* generate(const Position& pos, ExtMove* moveList) {
 
   Color us = pos.side_to_move();
 
-  Bitboard target =  Type == CAPTURES     ?  pos.pieces(~us)
-                   : Type == QUIETS       ? ~pos.pieces()
-                   : Type == NON_EVASIONS ? ~pos.pieces(us) : 0;
-
-  return us == WHITE ? generate_all<WHITE, Type>(pos, moveList, target)
-                     : generate_all<BLACK, Type>(pos, moveList, target);
+  return us == WHITE ? generate_all<WHITE, Type>(pos, moveList)
+                     : generate_all<BLACK, Type>(pos, moveList);
 }
 
 // Explicit template instantiations
@@ -284,16 +296,13 @@ ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* moveList) {
   assert(!pos.checkers());
 
   Color us = pos.side_to_move();
-  Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us);
+  Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us) & ~pos.pieces(PAWN);
 
   while (dc)
   {
      Square from = pop_lsb(&dc);
      PieceType pt = type_of(pos.piece_on(from));
 
-     if (pt == PAWN)
-         continue; // Will be generated together with direct checks
-
      Bitboard b = pos.attacks_from(pt, from) & ~pos.pieces();
 
      if (pt == KING)
@@ -303,8 +312,8 @@ ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* moveList) {
          *moveList++ = make_move(from, pop_lsb(&b));
   }
 
-  return us == WHITE ? generate_all<WHITE, QUIET_CHECKS>(pos, moveList, ~pos.pieces())
-                     : generate_all<BLACK, QUIET_CHECKS>(pos, moveList, ~pos.pieces());
+  return us == WHITE ? generate_all<WHITE, QUIET_CHECKS>(pos, moveList)
+                     : generate_all<BLACK, QUIET_CHECKS>(pos, moveList);
 }
 
 
@@ -324,10 +333,7 @@ ExtMove* generate<EVASIONS>(const Position& pos, ExtMove* moveList) {
   // the king evasions in order to skip known illegal moves, which avoids any
   // useless legality checks later on.
   while (sliders)
-  {
-      Square checksq = pop_lsb(&sliders);
-      sliderAttacks |= LineBB[checksq][ksq] ^ checksq;
-  }
+      sliderAttacks |= LineBB[ksq][pop_lsb(&sliders)] & ~pos.checkers();
 
   // Generate evasions for king, capture and non capture moves
   Bitboard b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
@@ -338,11 +344,8 @@ ExtMove* generate<EVASIONS>(const Position& pos, ExtMove* moveList) {
       return moveList; // Double check, only a king move can save the day
 
   // Generate blocking evasions or captures of the checking piece
-  Square checksq = lsb(pos.checkers());
-  Bitboard target = between_bb(checksq, ksq) | checksq;
-
-  return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, moveList, target)
-                     : generate_all<BLACK, EVASIONS>(pos, moveList, target);
+  return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, moveList)
+                     : generate_all<BLACK, EVASIONS>(pos, moveList);
 }