Tune null search reduction

[stockfish] / src / bitbase.cpp

diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index 6094f50fbe9da0b9bca1bc3e47927bc35f43f977..57fc50167923da8eebca6e4658b8e4cbf151a1b9 100644 (file)
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -41,7 +41,7 @@ namespace {
   // bit 13-14: white pawn file (from FILE_A to FILE_D)
   // bit 15-17: white pawn RANK_7 - rank (from RANK_7 - RANK_7 to RANK_7 - RANK_2)
   unsigned index(Color us, Square bksq, Square wksq, Square psq) {
-    return wksq + (bksq << 6) + (us << 12) + (file_of(psq) << 13) + ((RANK_7 - rank_of(psq)) << 15);
+    return wksq | (bksq << 6) | (us << 12) | (file_of(psq) << 13) | ((RANK_7 - rank_of(psq)) << 15);
   }
 
   enum Result {
@@ -71,7 +71,7 @@ namespace {
 } // namespace
 
 
-bool Bitbases::probe_kpk(Square wksq, Square wpsq, Square bksq, Color us) {
+bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color us) {
 
   assert(file_of(wpsq) <= FILE_D);
 
@@ -80,7 +80,7 @@ bool Bitbases::probe_kpk(Square wksq, Square wpsq, Square bksq, Color us) {
 }
 
 
-void Bitbases::init_kpk() {
+void Bitbases::init() {
 
   unsigned idx, repeat = 1;
   std::vector<KPKPosition> db;
@@ -107,14 +107,14 @@ namespace {
 
   KPKPosition::KPKPosition(unsigned idx) {
 
-    wksq = Square((idx >>  0) & 0x3F);
-    bksq = Square((idx >>  6) & 0x3F);
-    us   = Color ((idx >> 12) & 0x01);
-    psq  = make_square(File((idx >> 13) & 0x03), Rank(RANK_7 - (idx >> 15)));
-    result  = UNKNOWN;
+    wksq   = Square((idx >>  0) & 0x3F);
+    bksq   = Square((idx >>  6) & 0x3F);
+    us     = Color ((idx >> 12) & 0x01);
+    psq    = make_square(File((idx >> 13) & 0x3), RANK_7 - Rank((idx >> 15) & 0x7));
+    result = UNKNOWN;
 
     // Check if two pieces are on the same square or if a king can be captured
-    if (   square_distance(wksq, bksq) <= 1
+    if (   distance(wksq, bksq) <= 1
         || wksq == psq
         || bksq == psq
         || (us == WHITE && (StepAttacksBB[PAWN][psq] & bksq)))
@@ -125,7 +125,7 @@ namespace {
         // Immediate win if a pawn can be promoted without getting captured
         if (   rank_of(psq) == RANK_7
             && wksq != psq + DELTA_N
-            && (   square_distance(bksq, psq + DELTA_N) > 1
+            && (   distance(bksq, psq + DELTA_N) > 1
                 ||(StepAttacksBB[KING][wksq] & (psq + DELTA_N))))
             result = WIN;
     }