From: Marco Costalba <mcostalba@gmail.com>
Date: Tue, 1 May 2012 11:17:08 +0000 (+0100)
Subject: Simplify attacks_bb()
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=2f47844c7cb34c7de5b5d41cda10b7d8736a20bc

Simplify attacks_bb()

And some formatting while there.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---

diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index d0e4f51d..1bae6843 100644
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -168,30 +168,27 @@ void Bitboards::init() {
   FileBB[FILE_A] = FileABB;
   RankBB[RANK_1] = Rank1BB;
 
-  for (int f = FILE_B; f <= FILE_H; f++)
+  for (int i = 1; i < 8; i++)
   {
-      FileBB[f] = FileBB[f - 1] << 1;
-      RankBB[f] = RankBB[f - 1] << 8;
+      FileBB[i] = FileBB[i - 1] << 1;
+      RankBB[i] = RankBB[i - 1] << 8;
   }
 
-  for (int f = FILE_A; f <= FILE_H; f++)
+  for (File f = FILE_A; f <= FILE_H; f++)
   {
       AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0);
       ThisAndAdjacentFilesBB[f] = FileBB[f] | AdjacentFilesBB[f];
   }
 
-  for (int rw = RANK_7, rb = RANK_2; rw >= RANK_1; rw--, rb++)
-  {
-      InFrontBB[WHITE][rw] = InFrontBB[WHITE][rw + 1] | RankBB[rw + 1];
-      InFrontBB[BLACK][rb] = InFrontBB[BLACK][rb - 1] | RankBB[rb - 1];
-  }
+  for (Rank r = RANK_1; r < RANK_8; r++)
+      InFrontBB[WHITE][r] = ~(InFrontBB[BLACK][r + 1] = InFrontBB[BLACK][r] | RankBB[r]);
 
   for (Color c = WHITE; c <= BLACK; c++)
       for (Square s = SQ_A1; s <= SQ_H8; s++)
       {
-          ForwardBB[c][s]      = in_front_bb(c, s) & file_bb(s);
-          PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(file_of(s));
-          AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(file_of(s));
+          ForwardBB[c][s]      = InFrontBB[c][rank_of(s)] & FileBB[file_of(s)];
+          PassedPawnMask[c][s] = InFrontBB[c][rank_of(s)] & ThisAndAdjacentFilesBB[file_of(s)];
+          AttackSpanMask[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)];
       }
 
   for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
@@ -231,9 +228,8 @@ void Bitboards::init() {
 
   for (Square s = SQ_A1; s <= SQ_H8; s++)
   {
-      PseudoAttacks[BISHOP][s] = attacks_bb<BISHOP>(s, 0);
-      PseudoAttacks[ROOK][s]   = attacks_bb<ROOK>(s, 0);
-      PseudoAttacks[QUEEN][s]  = PseudoAttacks[BISHOP][s] | PseudoAttacks[ROOK][s];
+      PseudoAttacks[QUEEN][s]  = PseudoAttacks[BISHOP][s] = attacks_bb<BISHOP>(s, 0);
+      PseudoAttacks[QUEEN][s] |= PseudoAttacks[  ROOK][s] = attacks_bb<  ROOK>(s, 0);
   }
 
   for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
diff --git a/src/bitboard.h b/src/bitboard.h
index 59b30a7f..cc039397 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -216,8 +216,7 @@ FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
 
 template<PieceType Pt>
 inline Bitboard attacks_bb(Square s, Bitboard occ) {
-  Bitboard** const Attacks = Pt == ROOK ? RAttacks : BAttacks;
-  return Attacks[s][magic_index<Pt>(s, occ)];
+  return (Pt == ROOK ? RAttacks : BAttacks)[s][magic_index<Pt>(s, occ)];
 }