From: Marco Costalba <mcostalba@gmail.com>
Date: Wed, 4 Dec 2013 16:24:32 +0000 (+0100)
Subject: Retire TheirHalf[]
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=b71cedb2b009adfd19e9f25c298ac6bd0304dcfc

Retire TheirHalf[]

We avoid to use an ad-hoc table at the cost of a
relative_rank() call in advanced_pawn_push().

On my 32 bit system it is even slightly faster (on 64bit
may be different). This is the speed in nps alternating
old and new bench runs:

new

368890
368825
369972

old

367798
367635
368026

No functional change.
---

diff --git a/src/bitboard.h b/src/bitboard.h
index ceac2c24..8154f574 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -84,8 +84,6 @@ extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
 extern int SquareDistance[SQUARE_NB][SQUARE_NB];
 
 const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
-const Bitboard TheirHalf[COLOR_NB] = { Rank5BB | Rank6BB | Rank7BB | Rank8BB,
-                                       Rank1BB | Rank2BB | Rank3BB | Rank4BB };
 
 /// Overloads of bitwise operators between a Bitboard and a Square for testing
 /// whether a given bit is set in a bitboard, and for setting and clearing bits.
diff --git a/src/position.h b/src/position.h
index 6defeb22..4e15bb13 100644
--- a/src/position.h
+++ b/src/position.h
@@ -327,7 +327,8 @@ inline bool Position::pawn_passed(Color c, Square s) const {
 }
 
 inline bool Position::advanced_pawn_push(Move m) const {
-  return pieces(PAWN) & TheirHalf[sideToMove] & from_sq(m);
+  return   type_of(moved_piece(m)) == PAWN
+        && relative_rank(sideToMove, from_sq(m)) > RANK_4;
 }
 
 inline Key Position::key() const {