Simplify attacks_bb()

mcostalba · mcostalba · commit 2f47844c7cb3 · 2012-05-01T13:16:20.000+01:00
And some formatting while there.

No functional change.

Signed-off-by: Marco Costalba &lt;mcostalba@gmail.com&gt;
diff --git 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
@@ -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)];
 }
 
 

Original file line number	Diff line number	Diff line change
`@@ -168,30 +168,27 @@ void Bitboards::init() {`
`168`	`168`	`FileBB[FILE_A] = FileABB;`
`169`	`169`	`RankBB[RANK_1] = Rank1BB;`
`170`	`170`
`171`		`- for (int f = FILE_B; f <= FILE_H; f++)`
	`171`	`+ for (int i = 1; i < 8; i++)`
`172`	`172`	`{`
`173`		`- FileBB[f] = FileBB[f - 1] << 1;`
`174`		`- RankBB[f] = RankBB[f - 1] << 8;`
	`173`	`+ FileBB[i] = FileBB[i - 1] << 1;`
	`174`	`+ RankBB[i] = RankBB[i - 1] << 8;`
`175`	`175`	`}`
`176`	`176`
`177`		`- for (int f = FILE_A; f <= FILE_H; f++)`
	`177`	`+ for (File f = FILE_A; f <= FILE_H; f++)`
`178`	`178`	`{`
`179`	`179`	`AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) \| (f < FILE_H ? FileBB[f + 1] : 0);`
`180`	`180`	`ThisAndAdjacentFilesBB[f] = FileBB[f] \| AdjacentFilesBB[f];`
`181`	`181`	`}`
`182`	`182`
`183`		`- for (int rw = RANK_7, rb = RANK_2; rw >= RANK_1; rw--, rb++)`
`184`		`- {`
`185`		`- InFrontBB[WHITE][rw] = InFrontBB[WHITE][rw + 1] \| RankBB[rw + 1];`
`186`		`- InFrontBB[BLACK][rb] = InFrontBB[BLACK][rb - 1] \| RankBB[rb - 1];`
`187`		`- }`
	`183`	`+ for (Rank r = RANK_1; r < RANK_8; r++)`
	`184`	`+ InFrontBB[WHITE][r] = ~(InFrontBB[BLACK][r + 1] = InFrontBB[BLACK][r] \| RankBB[r]);`
`188`	`185`
`189`	`186`	`for (Color c = WHITE; c <= BLACK; c++)`
`190`	`187`	`for (Square s = SQ_A1; s <= SQ_H8; s++)`
`191`	`188`	`{`
`192`		`- ForwardBB[c][s] = in_front_bb(c, s) & file_bb(s);`
`193`		`- PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(file_of(s));`
`194`		`- AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(file_of(s));`
	`189`	`+ ForwardBB[c][s] = InFrontBB[c][rank_of(s)] & FileBB[file_of(s)];`
	`190`	`+ PassedPawnMask[c][s] = InFrontBB[c][rank_of(s)] & ThisAndAdjacentFilesBB[file_of(s)];`
	`191`	`+ AttackSpanMask[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)];`
`195`	`192`	`}`
`196`	`193`
`197`	`194`	`for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)`
`@@ -231,9 +228,8 @@ void Bitboards::init() {`
`231`	`228`
`232`	`229`	`for (Square s = SQ_A1; s <= SQ_H8; s++)`
`233`	`230`	`{`
`234`		`- PseudoAttacks[BISHOP][s] = attacks_bb<BISHOP>(s, 0);`
`235`		`- PseudoAttacks[ROOK][s] = attacks_bb<ROOK>(s, 0);`
`236`		`- PseudoAttacks[QUEEN][s] = PseudoAttacks[BISHOP][s] \| PseudoAttacks[ROOK][s];`
	`231`	`+ PseudoAttacks[QUEEN][s] = PseudoAttacks[BISHOP][s] = attacks_bb<BISHOP>(s, 0);`
	`232`	`+ PseudoAttacks[QUEEN][s] \|= PseudoAttacks[ ROOK][s] = attacks_bb< ROOK>(s, 0);`
`237`	`233`	`}`
`238`	`234`
`239`	`235`	`for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)`
Original file line number	Diff line number	Diff line change
`@@ -216,8 +216,7 @@ FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {`
`216`	`216`
`217`	`217`	`template<PieceType Pt>`
`218`	`218`	`inline Bitboard attacks_bb(Square s, Bitboard occ) {`
`219`		`- Bitboard** const Attacks = Pt == ROOK ? RAttacks : BAttacks;`
`220`		`- return Attacks[s][magic_index<Pt>(s, occ)];`
	`219`	`+ return (Pt == ROOK ? RAttacks : BAttacks)[s][magic_index<Pt>(s, occ)];`
`221`	`220`	`}`
`222`	`221`
`223`	`222`