X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fposition.cpp;h=fd3f8035f30251c18211e633b835fc8fb49fc410;hb=27f2ce8f6e8462bd9be4b201dd95fc2df17aafe6;hp=6885b135cafad835c691087a336ba9d66708228e;hpb=490f67a3f89449e243c3e85feb13679f388d9e22;p=stockfish

diff --git a/src/position.cpp b/src/position.cpp
index 6885b135..fd3f8035 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1149,9 +1149,9 @@ void Position::clear() {
   startState.epSquare = SQ_NONE;
   st = &startState;
 
-  for (int i = 0; i < 8; i++)
+  for (int i = 0; i < PIECE_TYPE_NB; i++)
       for (int j = 0; j < 16; j++)
-          pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
+          pieceList[WHITE][i][j] = pieceList[BLACK][i][j] = SQ_NONE;
 }
 
 
@@ -1255,17 +1255,20 @@ Value Position::compute_non_pawn_material(Color c) const {
 }
 
 
-/// Position::is_draw() tests whether the position is drawn by repetition
-/// or the 50 moves rule. It does not detect stalemates, this must be done
-/// by the search.
-
+/// Position::is_draw() tests whether the position is drawn by material,
+/// repetition, or the 50 moves rule. It does not detect stalemates, this
+/// must be done by the search.
 bool Position::is_draw() const {
 
+  // Draw by material?
+  if (   !pieces(PAWN)
+      && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMg))
+      return true;
+
   // Draw by the 50 moves rule?
   if (st->rule50 > 99 && (!checkers() || MoveList<LEGAL>(*this).size()))
       return true;
 
-  // Draw by repetition?
   int i = 4, e = std::min(st->rule50, st->pliesFromNull);
 
   if (i <= e)
@@ -1276,7 +1279,7 @@ bool Position::is_draw() const {
           stp = stp->previous->previous;
 
           if (stp->key == st->key)
-              return true;
+              return true; // Draw after first repetition
 
           i += 2;