Micro optimize and rename move_promotion()

[stockfish] / src / movegen.cpp

diff --git a/src/movegen.cpp b/src/movegen.cpp
index a783a6251b8b7ca6319d127cb7b1eb8842fa8dbb..33da450ec8e0452eb90daafed75df7cd91740ec1 100644 (file)
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -24,6 +24,7 @@
 
 #include <cassert>
 
+#include "bitcount.h"
 #include "movegen.h"
 
 // Simple macro to wrap a very common while loop, no facny, no flexibility,
@@ -131,7 +132,7 @@ namespace {
 
 
 /// generate_captures generates() all pseudo-legal captures and queen
-/// promotions.  The return value is the number of moves generated.
+/// promotions. The return value is the number of moves generated.
 
 int generate_captures(const Position& pos, MoveStack* mlist) {
 
@@ -392,7 +393,6 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   assert(pinned == pos.pinned_pieces(pos.side_to_move()));
 
   Color us = pos.side_to_move();
-  Color them = opposite_color(us);
   Square from = move_from(m);
   Piece pc = pos.piece_on(from);
 
@@ -401,6 +401,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   if (color_of_piece(pc) != us)
       return false;
 
+  Color them = opposite_color(us);
   Square to = move_to(m);
 
   // En passant moves
@@ -505,7 +506,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
       // be a promotion.
       if (   (  (square_rank(to) == RANK_8 && us == WHITE)
               ||(square_rank(to) == RANK_1 && us != WHITE))
-           && !move_promotion(m))
+           && !move_is_promotion(m))
           return false;
 
       // Proceed according to the square delta between the source and
@@ -559,7 +560,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   // Luckly we can handle all the other pieces in one go
   return (   pos.piece_attacks_square(pos.piece_on(from), from, to)
           && pos.pl_move_is_legal(m, pinned)
-          && !move_promotion(m));
+          && !move_is_promotion(m));
 }
 
 
@@ -790,9 +791,11 @@ namespace {
     // Direct checks. These are possible only for pawns on neighboring files
     // and in the two ranks that, after the push, are in front of the enemy king.
     b1 = pawns & neighboring_files_bb(ksq) & ~dc;
-    b2 = rank_bb(ksq + 2 * TDELTA_S) | rank_bb(ksq + 3 * TDELTA_S);
-    b1 &= b2;
-    if (!b1)
+
+    // We can get false positives if (ksq + x) is not in [0,63] range but
+    // is not a problem, they will be filtered out later.
+    b2 = b1 & (rank_bb(ksq + 2 * TDELTA_S) | rank_bb(ksq + 3 * TDELTA_S));
+    if (!b2)
         return mlist;
 
     // Direct checks, single pawn pushes