Partially restore HistoryMax

Should be not useful but better safe than sorry.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/history.h b/src/history.h
index 9206cdf4bc7d8a45ad34612e12244ec23a55dcc2..47543d54db7ad2995791246a763e843c5bf79464 100644 (file)
--- a/src/history.h
+++ b/src/history.h
@@ -45,6 +45,8 @@ public:
   Value gain(Piece p, Square to) const;
   void update_gain(Piece p, Square to, Value delta);
 
+  static const int MaxValue = (1 << 29); // To avoid an overflow
+
 private:
   Value history[16][64];  // [piece][to_square]
   Value maxGains[16][64]; // [piece][to_square]
@@ -60,7 +62,7 @@ inline int History::value(Piece p, Square to) const {
 }
 
 inline void History::update(Piece p, Square to, Value bonus) {
-  history[p][to] += bonus;
+  if (abs(history[p][to]) < MaxValue) history[p][to] += bonus;
 }
 
 inline Value History::gain(Piece p, Square to) const {
@@ -68,11 +70,7 @@ inline Value History::gain(Piece p, Square to) const {
 }
 
 inline void History::update_gain(Piece p, Square to, Value gain) {
-
-  if (gain >= maxGains[p][to])
-      maxGains[p][to] = gain;
-  else
-      maxGains[p][to]--;
+  maxGains[p][to] = (gain >= maxGains[p][to] ? gain : maxGains[p][to] - 1);
 }
 
 #endif // !defined(HISTORY_H_INCLUDED)

diff --git a/src/movepick.cpp b/src/movepick.cpp
index ab79c22f2f5cf560cccf99b17d3b57df8dd1df70..aa6f7c19bc9ac9aa45b5368133d7010f155f32ee 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -247,10 +247,10 @@ void MovePicker::score_evasions() {
   {
       m = cur->move;
       if ((seeScore = pos.see_sign(m)) < 0)
-          cur->score = seeScore - (1 << 29); // Be sure are at the bottom
+          cur->score = seeScore - History::MaxValue; // Be sure we are at the bottom
       else if (pos.move_is_capture(m))
           cur->score =  pos.midgame_value_of_piece_on(move_to(m))
-                      - pos.type_of_piece_on(move_from(m)) + (1 << 29);
+                      - pos.type_of_piece_on(move_from(m)) + History::MaxValue;
       else
           cur->score = H.value(pos.piece_on(move_from(m)), move_to(m));
   }