X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=51d85192a7c4df8b9c0cfdd0ea0c3adfb7b9ff13;hp=33c65670ffe10afd9c738b1ddf5ac4e9f95f687c;hb=8dd6875240e05dbcc1fb6467ffb11ad360aa474c;hpb=c769d4df84f0d4f6290956250c28460b66d95eeb

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 33c65670..51d85192 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -2,7 +2,7 @@
   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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, 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
@@ -27,10 +27,8 @@ namespace {
   enum Stages {
     MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLERS, COUNTERMOVE, QUIET_INIT, QUIET, BAD_CAPTURES,
     EVASION, EVASIONS_INIT, ALL_EVASIONS,
-    PROBCUT, PROBCUT_INIT, PROBCUT_CAPTURES,
-    QSEARCH_WITH_CHECKS, QCAPTURES_1_INIT, QCAPTURES_1, QCHECKS,
-    QSEARCH_NO_CHECKS, QCAPTURES_2_INIT, QCAPTURES_2,
-    QSEARCH_RECAPTURES, QRECAPTURES
+    PROBCUT, PROBCUT_CAPTURES_INIT, PROBCUT_CAPTURES,
+    QSEARCH, QCAPTURES_INIT, QCAPTURES, QCHECKS, QSEARCH_RECAPTURES, QRECAPTURES
   };
 
   // partial_insertion_sort() sorts moves in descending order up to and including
@@ -81,18 +79,15 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHist
 
 /// MovePicker constructor for quiescence search
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,  const CapturePieceToHistory* cph, Square s)
-           : pos(p), mainHistory(mh), captureHistory(cph) {
+           : pos(p), mainHistory(mh), captureHistory(cph), depth(d) {
 
   assert(d <= DEPTH_ZERO);
 
   if (pos.checkers())
       stage = EVASION;
 
-  else if (d > DEPTH_QS_NO_CHECKS)
-      stage = QSEARCH_WITH_CHECKS;
-
   else if (d > DEPTH_QS_RECAPTURES)
-      stage = QSEARCH_NO_CHECKS;
+      stage = QSEARCH;
 
   else
   {
@@ -161,17 +156,21 @@ Move MovePicker::next_move(bool skipQuiets) {
 
   switch (stage) {
 
-  case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS:
-  case QSEARCH_NO_CHECKS: case PROBCUT:
+  case MAIN_SEARCH: case EVASION: case QSEARCH: case PROBCUT:
       ++stage;
       return ttMove;
 
   case CAPTURES_INIT:
+  case PROBCUT_CAPTURES_INIT:
+  case QCAPTURES_INIT:
+  case QSEARCH_RECAPTURES:
       endBadCaptures = cur = moves;
       endMoves = generate<CAPTURES>(pos, cur);
       score<CAPTURES>();
       ++stage;
-      /* fallthrough */
+
+      // Rebranch at the top of the switch via a recursive call
+      return next_move(skipQuiets);
 
   case GOOD_CAPTURES:
       while (cur < endMoves)
@@ -179,12 +178,7 @@ Move MovePicker::next_move(bool skipQuiets) {
           move = pick_best(cur++, endMoves);
           if (move != ttMove)
           {
-              if (pos.see_ge(move))
-                  return move;
-
-              if (   type_of(pos.piece_on(to_sq(move))) == KNIGHT
-                  && type_of(pos.moved_piece(move)) == BISHOP
-                  && (cur-1)->value > 1090)
+              if (pos.see_ge(move, Value(-55 * (cur-1)->value / 1024)))
                   return move;
 
               // Losing capture, move it to the beginning of the array
@@ -232,17 +226,17 @@ Move MovePicker::next_move(bool skipQuiets) {
       /* fallthrough */
 
   case QUIET:
-      while (    cur < endMoves
-             && (!skipQuiets || cur->value >= VALUE_ZERO))
-      {
-          move = *cur++;
-
-          if (   move != ttMove
-              && move != killers[0]
-              && move != killers[1]
-              && move != countermove)
-              return move;
-      }
+      if (!skipQuiets)
+         while (cur < endMoves)
+         {
+             move = *cur++;
+
+             if (   move != ttMove
+                 && move != killers[0]
+                 && move != killers[1]
+                 && move != countermove)
+                 return move;
+         }
       ++stage;
       cur = moves; // Point to beginning of bad captures
       /* fallthrough */
@@ -268,13 +262,6 @@ Move MovePicker::next_move(bool skipQuiets) {
       }
       break;
 
-  case PROBCUT_INIT:
-      cur = moves;
-      endMoves = generate<CAPTURES>(pos, cur);
-      score<CAPTURES>();
-      ++stage;
-      /* fallthrough */
-
   case PROBCUT_CAPTURES:
       while (cur < endMoves)
       {
@@ -285,21 +272,14 @@ Move MovePicker::next_move(bool skipQuiets) {
       }
       break;
 
-  case QCAPTURES_1_INIT: case QCAPTURES_2_INIT:
-      cur = moves;
-      endMoves = generate<CAPTURES>(pos, cur);
-      score<CAPTURES>();
-      ++stage;
-      /* fallthrough */
-
-  case QCAPTURES_1: case QCAPTURES_2:
+  case QCAPTURES:
       while (cur < endMoves)
       {
           move = pick_best(cur++, endMoves);
           if (move != ttMove)
               return move;
       }
-      if (stage == QCAPTURES_2)
+      if (depth <= DEPTH_QS_NO_CHECKS)
           break;
       cur = moves;
       endMoves = generate<QUIET_CHECKS>(pos, cur);
@@ -315,17 +295,10 @@ Move MovePicker::next_move(bool skipQuiets) {
       }
       break;
 
-  case QSEARCH_RECAPTURES:
-      cur = moves;
-      endMoves = generate<CAPTURES>(pos, cur);
-      score<CAPTURES>();
-      ++stage;
-      /* fallthrough */
-
   case QRECAPTURES:
       while (cur < endMoves)
       {
-          move = pick_best(cur++, endMoves);
+          move = *cur++;
           if (to_sq(move) == recaptureSquare)
               return move;
       }