X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=639ef3f06e968d7249c55ff45748577a9e6cfefa;hp=945169c36d5ae8544078873ae43a686a6a825437;hb=6008f6538e9c3912c88e89d77ef3e3d3351a6e55;hpb=6b5322ce000d6a8a6f845beda2d7e149e1baea0c

diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 945169c3..639ef3f0 100644
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -23,6 +23,7 @@
 
 #include "bitboard.h"
 #include "bitcount.h"
+#include "misc.h"
 #include "rkiss.h"
 
 CACHE_LINE_ALIGNMENT
@@ -55,6 +56,10 @@ int SquareDistance[64][64];
 
 namespace {
 
+  // De Bruijn sequences. See chessprogramming.wikispaces.com/BitScan
+  const uint64_t DeBruijn_64 = 0x218A392CD3D5DBFULL;
+  const uint32_t DeBruijn_32 = 0x783A9B23;
+
   CACHE_LINE_ALIGNMENT
 
   int BSFTable[64];
@@ -77,11 +82,11 @@ namespace {
 Square lsb(Bitboard b) {
 
   if (Is64Bit)
-      return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]);
+      return Square(BSFTable[((b & -b) * DeBruijn_64) >> 58]);
 
   b ^= (b - 1);
   uint32_t fold = unsigned(b) ^ unsigned(b >> 32);
-  return Square(BSFTable[(fold * 0x783A9B23) >> 26]);
+  return Square(BSFTable[(fold * DeBruijn_32) >> 26]);
 }
 
 Square pop_lsb(Bitboard* b) {
@@ -90,11 +95,11 @@ Square pop_lsb(Bitboard* b) {
   *b = bb & (bb - 1);
 
   if (Is64Bit)
-      return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]);
+      return Square(BSFTable[((bb & -bb) * DeBruijn_64) >> 58]);
 
   bb ^= (bb - 1);
   uint32_t fold = unsigned(bb) ^ unsigned(bb >> 32);
-  return Square(BSFTable[(fold * 0x783A9B23) >> 26]);
+  return Square(BSFTable[(fold * DeBruijn_32) >> 26]);
 }
 
 Square msb(Bitboard b) {
@@ -133,6 +138,8 @@ Square msb(Bitboard b) {
 
 void Bitboards::print(Bitboard b) {
 
+  sync_cout;
+
   for (Rank rank = RANK_8; rank >= RANK_1; rank--)
   {
       std::cout << "+---+---+---+---+---+---+---+---+" << '\n';
@@ -142,7 +149,7 @@ void Bitboards::print(Bitboard b) {
 
       std::cout << "|\n";
   }
-  std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
+  std::cout << "+---+---+---+---+---+---+---+---+" << sync_endl;
 }
 
 
@@ -203,10 +210,10 @@ void Bitboards::init() {
           Bitboard b = 1ULL << i;
           b ^= b - 1;
           b ^= b >> 32;
-          BSFTable[(uint32_t)(b * 0x783A9B23) >> 26] = i;
+          BSFTable[(uint32_t)(b * DeBruijn_32) >> 26] = i;
       }
       else
-          BSFTable[((1ULL << i) * 0x218A392CD3D5DBFULL) >> 58] = i;
+          BSFTable[((1ULL << i) * DeBruijn_64) >> 58] = i;
 
   int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 },
                      {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } };