Fix divide by zero bug in late game

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index b74f0659b24a371a92a6184ce5c73a50ea57ae7c..c8c2e6d8c243db77d67b30afd109dfd2ea1fff4f 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -53,15 +53,14 @@ namespace {
 
   // Pawn chain membership bonus by file
   const Score ChainMember[FILE_NB][RANK_NB] = {
-    { S(0, 0), S(14, 0), S(16, 4), S(18,  9), S(56, 56), S(104, 208), S(236, 472) }, 
-    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
-    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
-    { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(66, 66), S(118, 236), S(254, 508) }, 
-    { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(66, 66), S(118, 236), S(254, 508) }, 
-    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
-    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
-    { S(0, 0), S(14, 0), S(16, 4), S(18,  9), S(56, 56), S(104, 208), S(236, 472) }
-  }; 
+  { S(0, 0), S(14, 0), S(16, 4), S(18,  9), S(28, 28), S(52, 104), S(118, 236) },
+  { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
+  { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
+  { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(33, 33), S(59, 118), S(127, 254) },
+  { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(33, 33), S(59, 118), S(127, 254) },
+  { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
+  { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
+  { S(0, 0), S(14, 0), S(16, 4), S(18,  9), S(28, 28), S(52, 104), S(118, 236) }};
 
   // Candidate passed pawn bonus by rank
   const Score CandidatePassed[RANK_NB] = {
@@ -98,7 +97,6 @@ namespace {
     Bitboard b;
     Square s;
     File f;
-    Rank r;
     bool passed, isolated, doubled, opposed, chain, backward, candidate;
     Score value = SCORE_ZERO;
     const Square* pl = pos.list<PAWN>(Us);
@@ -119,7 +117,6 @@ namespace {
         assert(pos.piece_on(s) == make_piece(Us, PAWN));
 
         f = file_of(s);
-        r = relative_rank(Us, s);
 
         // This file cannot be semi-open
         e->semiopenFiles[Us] &= ~(1 << f);
@@ -184,11 +181,11 @@ namespace {
             value -= Backward[opposed][f];
 
         if (chain)
-            value += opposed ? ChainMember[f][r] / 2 : ChainMember[f][r];
+            value += ChainMember[f][relative_rank(Us, s)];
 
         if (candidate)
         {
-            value += CandidatePassed[r];
+            value += CandidatePassed[relative_rank(Us, s)];
 
             if (!doubled)
                 e->candidatePawns[Us] |= s;
@@ -235,13 +232,13 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
   Rank rkUs, rkThem;
   File kf = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
 
-  for (int f = kf - 1; f <= kf + 1; ++f)
+  for (File f = kf - File(1); f <= kf + File(1); ++f)
   {
-      b = ourPawns & FileBB[f];
+      b = ourPawns & file_bb(f);
       rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
       safety -= ShelterWeakness[rkUs];
 
-      b  = theirPawns & FileBB[f];
+      b  = theirPawns & file_bb(f);
       rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
       safety -= StormDanger[rkUs == RANK_1 ? 0 : rkThem == rkUs + 1 ? 2 : 1][rkThem];
   }