Raise penalty for knight attacked by pawn

[stockfish] / src / bitbase.cpp

diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index 7322a00ff79587bb069c0abde373d328169d64c3..a018d3cdad7a087ee973238f495c4c8d7e46d5a2 100644 (file)
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -26,14 +26,14 @@
 namespace {
 
   // There are 24 possible pawn squares: the first 4 files and ranks from 2 to 7
-  const unsigned IndexMax = 2*24*64*64; // stm * psq * wksq * bksq = 196608
+  const unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
 
   // Each uint32_t stores results of 32 positions, one per bit
-  uint32_t KPKBitbase[IndexMax / 32];
+  uint32_t KPKBitbase[MAX_INDEX / 32];
 
   // A KPK bitbase index is an integer in [0, IndexMax] range
   //
-  // Information is mapped in a way that minimizes number of iterations:
+  // Information is mapped in a way that minimizes the number of iterations:
   //
   // bit  0- 5: white king square (from SQ_A1 to SQ_H8)
   // bit  6-11: black king square (from SQ_A1 to SQ_H8)
@@ -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);
 
@@ -80,24 +80,24 @@ 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;
-  db.reserve(IndexMax);
+  db.reserve(MAX_INDEX);
 
   // Initialize db with known win / draw positions
-  for (idx = 0; idx < IndexMax; ++idx)
+  for (idx = 0; idx < MAX_INDEX; ++idx)
       db.push_back(KPKPosition(idx));
 
   // Iterate through the positions until none of the unknown positions can be
   // changed to either wins or draws (15 cycles needed).
   while (repeat)
-      for (repeat = idx = 0; idx < IndexMax; ++idx)
+      for (repeat = idx = 0; idx < MAX_INDEX; ++idx)
           repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN);
 
   // Map 32 results into one KPKBitbase[] entry
-  for (idx = 0; idx < IndexMax; ++idx)
+  for (idx = 0; idx < MAX_INDEX; ++idx)
       if (db[idx] == WIN)
           KPKBitbase[idx / 32] |= 1 << (idx & 0x1F);
 }
@@ -107,14 +107,16 @@ namespace {
 
   KPKPosition::KPKPosition(unsigned idx) {
 
-    wksq = Square((idx >>  0) & 0x3F);
-    bksq = Square((idx >>  6) & 0x3F);
-    us   = Color ((idx >> 12) & 0x01);
-    psq  = 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 || wksq == psq || bksq == psq
+    if (   distance(wksq, bksq) <= 1
+        || wksq == psq
+        || bksq == psq
         || (us == WHITE && (StepAttacksBB[PAWN][psq] & bksq)))
         result = INVALID;
 
@@ -123,7 +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;
     }