X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fbitbase.cpp;h=27bf4095478db4bfc9209c660b124a984d243887;hb=2214fcecf7ae5d1d4165596bcd238b6e6bc909c1;hp=7bc4a65c25900324ecbed98f7db7ab1598d830f2;hpb=75dfdeac119d0ce71c36ba5ab4f33318f589b158;p=stockfish

diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index 7bc4a65c..27bf4095 100644
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -1,8 +1,6 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -19,20 +17,21 @@
 */
 
 #include <cassert>
-#include <numeric>
 #include <vector>
+#include <bitset>
 
 #include "bitboard.h"
 #include "types.h"
 
+namespace Stockfish {
+
 namespace {
 
   // There are 24 possible pawn squares: files A to D and ranks from 2 to 7.
   // Positions with the pawn on files E to H will be mirrored before probing.
   constexpr 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[MAX_INDEX / 32];
+  std::bitset<MAX_INDEX> KPKBitbase;
 
   // A KPK bitbase index is an integer in [0, IndexMax] range
   //
@@ -69,13 +68,11 @@ namespace {
 
 } // namespace
 
-
 bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color stm) {
 
   assert(file_of(wpsq) <= FILE_D);
 
-  unsigned idx = index(stm, bksq, wksq, wpsq);
-  return KPKBitbase[idx / 32] & (1 << (idx & 0x1F));
+  return KPKBitbase[index(stm, bksq, wksq, wpsq)];
 }
 
 
@@ -94,13 +91,12 @@ void Bitbases::init() {
       for (repeat = idx = 0; idx < MAX_INDEX; ++idx)
           repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN);
 
-  // Map 32 results into one KPKBitbase[] entry
+  // Fill the bitbase with the decisive results
   for (idx = 0; idx < MAX_INDEX; ++idx)
       if (db[idx] == WIN)
-          KPKBitbase[idx / 32] |= 1 << (idx & 0x1F);
+          KPKBitbase.set(idx);
 }
 
-
 namespace {
 
   KPKPosition::KPKPosition(unsigned idx) {
@@ -110,25 +106,25 @@ namespace {
     stm        = Color ((idx >> 12) & 0x01);
     psq        = make_square(File((idx >> 13) & 0x3), Rank(RANK_7 - ((idx >> 15) & 0x7)));
 
-    // Check if two pieces are on the same square or if a king can be captured
+    // Invalid if two pieces are on the same square or if a king can be captured
     if (   distance(ksq[WHITE], ksq[BLACK]) <= 1
         || ksq[WHITE] == psq
         || ksq[BLACK] == psq
-        || (stm == WHITE && (PawnAttacks[WHITE][psq] & ksq[BLACK])))
+        || (stm == WHITE && (pawn_attacks_bb(WHITE, psq) & ksq[BLACK])))
         result = INVALID;
 
-    // Immediate win if a pawn can be promoted without getting captured
+    // Win if the pawn can be promoted without getting captured
     else if (   stm == WHITE
              && rank_of(psq) == RANK_7
-             && ksq[stm] != psq + NORTH
-             && (    distance(ksq[~stm], psq + NORTH) > 1
-                 || (PseudoAttacks[KING][ksq[stm]] & (psq + NORTH))))
+             && ksq[WHITE] != psq + NORTH
+             && (    distance(ksq[BLACK], psq + NORTH) > 1
+                 || (distance(ksq[WHITE], psq + NORTH) == 1)))
         result = WIN;
 
-    // Immediate draw if it is a stalemate or a king captures undefended pawn
+    // Draw if it is stalemate or the black king can capture the pawn
     else if (   stm == BLACK
-             && (  !(PseudoAttacks[KING][ksq[stm]] & ~(PseudoAttacks[KING][ksq[~stm]] | PawnAttacks[~stm][psq]))
-                 || (PseudoAttacks[KING][ksq[stm]] & psq & ~PseudoAttacks[KING][ksq[~stm]])))
+             && (  !(attacks_bb<KING>(ksq[BLACK]) & ~(attacks_bb<KING>(ksq[WHITE]) | pawn_attacks_bb(WHITE, psq)))
+                 || (attacks_bb<KING>(ksq[BLACK]) & ~attacks_bb<KING>(ksq[WHITE]) & psq)))
         result = DRAW;
 
     // Position will be classified later
@@ -151,11 +147,11 @@ namespace {
     const Result Bad  = (stm == WHITE ? DRAW  : WIN);
 
     Result r = INVALID;
-    Bitboard b = PseudoAttacks[KING][ksq[stm]];
+    Bitboard b = attacks_bb<KING>(ksq[stm]);
 
     while (b)
-        r |= stm == WHITE ? db[index(BLACK, ksq[BLACK] , pop_lsb(&b), psq)]
-                          : db[index(WHITE, pop_lsb(&b),  ksq[WHITE], psq)];
+        r |= stm == WHITE ? db[index(BLACK, ksq[BLACK], pop_lsb(b), psq)]
+                          : db[index(WHITE, pop_lsb(b), ksq[WHITE], psq)];
 
     if (stm == WHITE)
     {
@@ -172,3 +168,5 @@ namespace {
   }
 
 } // namespace
+
+} // namespace Stockfish