Introduce and use SCORE_ZERO

[stockfish] / src / bitboard.cpp

diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 384831adc8f7061f09797cbeff28d2e166eae574..0c38e182ba3633f5c6040f3f810d34de74657a6f 100644 (file)
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -163,7 +163,10 @@ const int RShift[64] = {
 
 #endif // defined(IS_64BIT)
 
-const Bitboard SquaresByColorBB[2] = { BlackSquaresBB, WhiteSquaresBB };
+const Bitboard LightSquaresBB = 0x55AA55AA55AA55AAULL;
+const Bitboard DarkSquaresBB  = 0xAA55AA55AA55AA55ULL;
+
+const Bitboard SquaresByColorBB[2] = { DarkSquaresBB, LightSquaresBB };
 
 const Bitboard FileBB[8] = {
   FileABB, FileBBB, FileCBB, FileDBB, FileEBB, FileFBB, FileGBB, FileHBB
@@ -226,8 +229,9 @@ Bitboard StepAttackBB[16][64];
 Bitboard RayBB[64][8];
 Bitboard BetweenBB[64][64];
 
+Bitboard SquaresInFrontMask[2][64];
 Bitboard PassedPawnMask[2][64];
-Bitboard OutpostMask[2][64];
+Bitboard AttackSpanMask[2][64];
 
 Bitboard BishopPseudoAttacks[64];
 Bitboard RookPseudoAttacks[64];
@@ -372,39 +376,6 @@ Square pop_1st_bit(Bitboard* bb) {
 
 #endif
 
-// Optimized bitScanReverse32() implementation by Pascal Georges. Note
-// that first bit is 1, this allow to differentiate between 0 and 1.
-static CACHE_LINE_ALIGNMENT
-const char MsbTable[256] = {
-  0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5,
-  5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
-  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
-  8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
-  8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
-  8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
-  8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
-  8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
-};
-
-int bitScanReverse32(uint32_t b)
-{
-   int result = 0;
-
-   if (b > 0xFFFF)
-   {
-      b >>= 16;
-      result += 16;
-   }
-   if (b > 0xFF)
-   {
-      b >>= 8;
-      result += 8;
-   }
-   return result + MsbTable[b];
-}
 
 namespace {
 
@@ -427,8 +398,9 @@ namespace {
     for (Color c = WHITE; c <= BLACK; c++)
         for (Square s = SQ_A1; s <= SQ_H8; s++)
         {
+            SquaresInFrontMask[c][s] = in_front_bb(c, s) & file_bb(s);
             PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_neighboring_files_bb(s);
-            OutpostMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s);
+            AttackSpanMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s);
         }
 
     for (Bitboard b = 0ULL; b < 256ULL; b++)