X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=b96b799542556a7f461e29d7b1472bf631689eab;hp=af530c5c3e6159b5b24da0ba633bc9fc770ef6d0;hb=7a68916ff992115d8013e7ce31850aec558d8ac5;hpb=20224a5bbf2844b5b64eec1de199c2d51b8d93d4

diff --git a/src/movepick.cpp b/src/movepick.cpp
index af530c5c..b96b7995 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -23,11 +23,9 @@
 //// Includes
 ////
 
-#include <algorithm>
 #include <cassert>
 
 #include "history.h"
-#include "evaluate.h"
 #include "movegen.h"
 #include "movepick.h"
 #include "search.h"
@@ -40,14 +38,23 @@
 
 namespace {
 
-  /// Variables
-
-  MovePicker::MovegenPhase PhaseTable[32];
-  int MainSearchPhaseIndex;
-  int EvasionsPhaseIndex;
-  int QsearchWithChecksPhaseIndex;
-  int QsearchWithoutChecksPhaseIndex;
-
+  enum MovegenPhase {
+    PH_TT_MOVES,       // Transposition table move and mate killer
+    PH_GOOD_CAPTURES,  // Queen promotions and captures with SEE values >= 0
+    PH_KILLERS,        // Killer moves from the current ply
+    PH_NONCAPTURES,    // Non-captures and underpromotions
+    PH_BAD_CAPTURES,   // Queen promotions and captures with SEE values < 0
+    PH_EVASIONS,       // Check evasions
+    PH_QCAPTURES,      // Captures in quiescence search
+    PH_QCHECKS,        // Non-capture checks in quiescence search
+    PH_STOP
+  };
+
+  CACHE_LINE_ALIGNMENT
+  const uint8_t MainSearchPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
+  const uint8_t EvasionsPhaseTable[] = { PH_TT_MOVES, PH_EVASIONS, PH_STOP};
+  const uint8_t QsearchWithChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP};
+  const uint8_t QsearchWithoutChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP};
 }
 
 
@@ -56,7 +63,7 @@ namespace {
 ////
 
 
-/// Constructor for the MovePicker class.  Apart from the position for which
+/// Constructor for the MovePicker class. Apart from the position for which
 /// it is asked to pick legal moves, MovePicker also wants some information
 /// to help it to return the presumably good moves first, to decide which
 /// moves to return (in the quiescence search, for instance, we only want to
@@ -65,164 +72,104 @@ namespace {
 
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
                        const History& h, SearchStack* ss) : pos(p), H(h) {
-  ttMove = ttm;
-  if (ss)
+  int searchTT = ttm;
+  ttMoves[0].move = ttm;
+  finished = false;
+  lastBadCapture = badCaptures;
+
+  pinned = p.pinned_pieces(pos.side_to_move());
+
+  if (ss && !p.is_check())
   {
-      mateKiller = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller;
-      killer1 = ss->killers[0];
-      killer2 = ss->killers[1];
+      ttMoves[1].move = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller;
+      searchTT |= ttMoves[1].move;
+      killers[0].move = ss->killers[0];
+      killers[1].move = ss->killers[1];
   } else
-      mateKiller = killer1 = killer2 = MOVE_NONE;
-
-  movesPicked = numOfMoves = numOfBadCaptures = 0;
-  checkKillers = checkLegal = finished = false;
+      ttMoves[1].move = killers[0].move = killers[1].move = MOVE_NONE;
 
   if (p.is_check())
-      phaseIndex = EvasionsPhaseIndex;
+      phasePtr = EvasionsPhaseTable;
   else if (d > Depth(0))
-      phaseIndex = MainSearchPhaseIndex;
+      phasePtr = MainSearchPhaseTable;
   else if (d == Depth(0))
-      phaseIndex = QsearchWithChecksPhaseIndex;
+      phasePtr = QsearchWithChecksPhaseTable;
   else
-      phaseIndex = QsearchWithoutChecksPhaseIndex;
+      phasePtr = QsearchWithoutChecksPhaseTable;
 
-  Color us = pos.side_to_move();
+  phasePtr += !searchTT - 1;
+  go_next_phase();
+}
 
-  dc = p.discovered_check_candidates(us);
-  pinned = p.pinned_pieces(us);
 
-  finished = false;
-}
+/// MovePicker::go_next_phase() generates, scores and sorts the next bunch
+/// of moves when there are no more moves to try for the current phase.
 
+void MovePicker::go_next_phase() {
 
-/// MovePicker::get_next_move() is the most important method of the MovePicker
-/// class.  It returns a new legal move every time it is called, until there
-/// are no more moves left of the types we are interested in.
+  curMove = moves;
+  phase = *(++phasePtr);
+  switch (phase) {
 
-Move MovePicker::get_next_move() {
+  case PH_TT_MOVES:
+      curMove = ttMoves;
+      lastMove = curMove + 2;
+      return;
 
-  Move move;
+  case PH_GOOD_CAPTURES:
+      lastMove = generate_captures(pos, moves);
+      score_captures();
+      return;
 
-  while (true)
-  {
-    // If we already have a list of generated moves, pick the best move from
-    // the list, and return it.
-    move = pick_move_from_list();
-    if (move != MOVE_NONE)
-    {
-        assert(move_is_ok(move));
-        return move;
-    }
-
-    // Next phase
-    phaseIndex++;
-    switch (PhaseTable[phaseIndex]) {
-
-    case PH_TT_MOVE:
-        if (ttMove != MOVE_NONE)
-        {
-            assert(move_is_ok(ttMove));
-            if (move_is_legal(pos, ttMove, pinned))
-                return ttMove;
-        }
-        break;
-
-    case PH_MATE_KILLER:
-        if (mateKiller != MOVE_NONE)
-        {
-            assert(move_is_ok(mateKiller));
-            if (move_is_legal(pos, mateKiller, pinned))
-                return mateKiller;
-        }
-        break;
-
-    case PH_GOOD_CAPTURES:
-        numOfMoves = generate_captures(pos, moves);
-        score_captures();
-        std::sort(moves, moves + numOfMoves);
-        movesPicked = 0;
-        break;
-
-    case PH_KILLERS:
-        movesPicked = numOfMoves = 0;
-        if (killer1 != MOVE_NONE && move_is_legal(pos, killer1, pinned) && !pos.move_is_capture(killer1))
-            moves[numOfMoves++].move = killer1;
-        if (killer2 != MOVE_NONE && move_is_legal(pos, killer2, pinned) && !pos.move_is_capture(killer2) )
-            moves[numOfMoves++].move = killer2;
-        break;
-
-    case PH_NONCAPTURES:
-        checkKillers = (numOfMoves != 0); // previous phase is PH_KILLERS
-        checkLegal = true;
-        numOfMoves = generate_noncaptures(pos, moves);
-        score_noncaptures();
-        std::sort(moves, moves + numOfMoves);
-        movesPicked = 0;
-        break;
-
-    case PH_BAD_CAPTURES:
-        // Bad captures SEE value is already calculated so just sort them
-        // to get SEE move ordering.
-        std::sort(badCaptures, badCaptures + numOfBadCaptures);
-        movesPicked = 0;
-        break;
-
-    case PH_EVASIONS:
-        assert(pos.is_check());
-        numOfMoves = generate_evasions(pos, moves, pinned);
-        score_evasions();
-        std::sort(moves, moves + numOfMoves);
-        movesPicked = 0;
-        break;
-
-    case PH_QCAPTURES:
-        numOfMoves = generate_captures(pos, moves);
-        score_captures();
-        std::sort(moves, moves + numOfMoves);
-        movesPicked = 0;
-        break;
-
-    case PH_QCHECKS:
-        // Perhaps we should order moves move here?  FIXME
-        numOfMoves = generate_non_capture_checks(pos, moves, dc);
-        movesPicked = 0;
-        break;
-
-    case PH_STOP:
-        return MOVE_NONE;
-
-    default:
-        assert(false);
-        return MOVE_NONE;
-    }
-  }
-}
+  case PH_KILLERS:
+      curMove = killers;
+      lastMove = curMove + 2;
+      return;
 
+  case PH_NONCAPTURES:
+      lastMove = generate_noncaptures(pos, moves);
+      score_noncaptures();
+      sort_moves(moves, lastMove);
+      return;
 
-/// A variant of get_next_move() which takes a lock as a parameter, used to
-/// prevent multiple threads from picking the same move at a split point.
+  case PH_BAD_CAPTURES:
+      // Bad captures SEE value is already calculated so just sort them
+      // to get SEE move ordering.
+      curMove = badCaptures;
+      lastMove = lastBadCapture;
+      return;
 
-Move MovePicker::get_next_move(Lock &lock) {
+  case PH_EVASIONS:
+      assert(pos.is_check());
+      lastMove = generate_evasions(pos, moves);
+      score_evasions();
+      return;
 
-   lock_grab(&lock);
-   if (finished)
-   {
-       lock_release(&lock);
-       return MOVE_NONE;
-   }
-   Move m = get_next_move();
-   if (m == MOVE_NONE)
-       finished = true;
+  case PH_QCAPTURES:
+      lastMove = generate_captures(pos, moves);
+      score_captures();
+      return;
 
-   lock_release(&lock);
-   return m;
+  case PH_QCHECKS:
+      // Perhaps we should order moves move here?  FIXME
+      lastMove = generate_non_capture_checks(pos, moves);
+      return;
+
+  case PH_STOP:
+      lastMove = curMove + 1; // hack to be friendly for get_next_move()
+      return;
+
+  default:
+      assert(false);
+      return;
+  }
 }
 
 
-/// MovePicker::score_captures(), MovePicker::score_noncaptures(),
-/// MovePicker::score_evasions() and MovePicker::score_qcaptures() assign a
-/// numerical move ordering score to each move in a move list.  The moves
-/// with highest scores will be picked first by pick_move_from_list().
+/// MovePicker::score_captures(), MovePicker::score_noncaptures() and
+/// MovePicker::score_evasions() assign a numerical move ordering score
+/// to each move in a move list.  The moves with highest scores will be
+/// picked first by get_next_move().
 
 void MovePicker::score_captures() {
   // Winning and equal captures in the main search are ordered by MVV/LVA.
@@ -241,14 +188,14 @@ void MovePicker::score_captures() {
   Move m;
 
   // Use MVV/LVA ordering
-  for (int i = 0; i < numOfMoves; i++)
+  for (MoveStack* cur = moves; cur != lastMove; cur++)
   {
-      m = moves[i].move;
+      m = cur->move;
       if (move_is_promotion(m))
-          moves[i].score = QueenValueMidgame;
+          cur->score = QueenValueMidgame;
       else
-          moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m)))
-                          -int(pos.type_of_piece_on(move_from(m)));
+          cur->score =  pos.midgame_value_of_piece_on(move_to(m))
+                      - pos.type_of_piece_on(move_from(m));
   }
 }
 
@@ -256,14 +203,16 @@ void MovePicker::score_noncaptures() {
   // First score by history, when no history is available then use
   // piece/square tables values. This seems to be better then a
   // random choice when we don't have an history for any move.
+  Move m;
   Piece piece;
   Square from, to;
   int hs;
 
-  for (int i = 0; i < numOfMoves; i++)
+  for (MoveStack* cur = moves; cur != lastMove; cur++)
   {
-      from = move_from(moves[i].move);
-      to = move_to(moves[i].move);
+      m = cur->move;
+      from = move_from(m);
+      to = move_to(m);
       piece = pos.piece_on(from);
       hs = H.move_ordering_score(piece, to);
 
@@ -272,137 +221,140 @@ void MovePicker::score_noncaptures() {
           hs += 1000;
 
       // pst based scoring
-      moves[i].score = hs + pos.pst_delta<Position::MidGame>(piece, from, to);
+      cur->score = hs + pos.pst_delta<Position::MidGame>(piece, from, to);
   }
 }
 
 void MovePicker::score_evasions() {
+  // Try good captures ordered by MVV/LVA, then non-captures if
+  // destination square is not under attack, ordered by history
+  // value, and at the end bad-captures and non-captures with a
+  // negative SEE. This last group is ordered by the SEE score.
+  Move m;
+  int seeScore;
 
-  for (int i = 0; i < numOfMoves; i++)
+  for (MoveStack* cur = moves; cur != lastMove; cur++)
   {
-      Move m = moves[i].move;
-      if (m == ttMove)
-          moves[i].score = 2*HistoryMax;
-      else if (!pos.square_is_empty(move_to(m)))
-      {
-          int seeScore = pos.see(m);
-          moves[i].score = (seeScore >= 0)? seeScore + HistoryMax : seeScore;
-      } else
-          moves[i].score = H.move_ordering_score(pos.piece_on(move_from(m)), move_to(m));
+      m = cur->move;
+      if ((seeScore = pos.see_sign(m)) < 0)
+          cur->score = seeScore;
+      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)) + HistoryMax;
+      else
+          cur->score = H.move_ordering_score(pos.piece_on(move_from(m)), move_to(m));
   }
 }
 
+/// MovePicker::get_next_move() is the most important method of the MovePicker
+/// class. It returns a new legal move every time it is called, until there
+/// are no more moves left.
+/// It picks the move with the biggest score from a list of generated moves taking
+/// care not to return the tt move if has already been searched previously.
 
-/// MovePicker::pick_move_from_list() picks the move with the biggest score
-/// from a list of generated moves (moves[] or badCaptures[], depending on
-/// the current move generation phase).  It takes care not to return the
-/// transposition table move if that has already been serched previously.
-
-Move MovePicker::pick_move_from_list() {
-
-  assert(movesPicked >= 0);
-  assert(!pos.is_check() || PhaseTable[phaseIndex] == PH_EVASIONS || PhaseTable[phaseIndex] == PH_STOP);
-  assert( pos.is_check() || PhaseTable[phaseIndex] != PH_EVASIONS);
+Move MovePicker::get_next_move() {
 
-  switch (PhaseTable[phaseIndex]) {
+  Move move;
 
-  case PH_GOOD_CAPTURES:
-      while (movesPicked < numOfMoves)
+  while (true)
+  {
+      while (curMove != lastMove)
       {
-          Move move = moves[movesPicked++].move;
-          if (   move != ttMove
-              && move != mateKiller
-              && pos.pl_move_is_legal(move, pinned))
-          {
-              // Check for a non negative SEE now
-              int seeValue = pos.see_sign(move);
-              if (seeValue >= 0)
+          switch (phase) {
+
+          case PH_TT_MOVES:
+              move = (curMove++)->move;
+              if (   move != MOVE_NONE
+                  && move_is_legal(pos, move, pinned))
                   return move;
+              break;
+
+          case PH_GOOD_CAPTURES:
+              move = pick_best(curMove++, lastMove).move;
+              if (   move != ttMoves[0].move
+                  && move != ttMoves[1].move
+                  && pos.pl_move_is_legal(move, pinned))
+              {
+                  // Check for a non negative SEE now
+                  int seeValue = pos.see_sign(move);
+                  if (seeValue >= 0)
+                      return move;
+
+                  // Losing capture, move it to the badCaptures[] array, note
+                  // that move has now been already checked for legality.
+                  assert(int(lastBadCapture - badCaptures) < 63);
+                  lastBadCapture->move = move;
+                  lastBadCapture->score = seeValue;
+                  lastBadCapture++;
+              }
+              break;
+
+          case PH_KILLERS:
+              move = (curMove++)->move;
+              if (   move != MOVE_NONE
+                  && move != ttMoves[0].move
+                  && move != ttMoves[1].move
+                  && move_is_legal(pos, move, pinned)
+                  && !pos.move_is_capture(move))
+                  return move;
+              break;
+
+          case PH_NONCAPTURES:
+              move = (curMove++)->move;
+              if (   move != ttMoves[0].move
+                  && move != ttMoves[1].move
+                  && move != killers[0].move
+                  && move != killers[1].move
+                  && pos.pl_move_is_legal(move, pinned))
+                  return move;
+              break;
 
-              // Losing capture, move it to the badCaptures[] array, note
-              // that move has now been already checked for legality.
-              assert(numOfBadCaptures < 63);
-              badCaptures[numOfBadCaptures].move = move;
-              badCaptures[numOfBadCaptures++].score = seeValue;
-          }
-      }
-      break;
-  case PH_KILLERS:
-  case PH_NONCAPTURES:
-      while (movesPicked < numOfMoves)
-      {
-          Move move = moves[movesPicked++].move;
-          if (   move != ttMove
-              && move != mateKiller
-              && (!checkKillers || (move != killer1 && move != killer2))
-              && (!checkLegal || pos.pl_move_is_legal(move, pinned)))
+          case PH_BAD_CAPTURES:
+              move = pick_best(curMove++, lastMove).move;
               return move;
-      }
-      break;
 
-  case PH_EVASIONS:
-      if (movesPicked < numOfMoves)
-          return moves[movesPicked++].move;
-      break;
+          case PH_EVASIONS:
+          case PH_QCAPTURES:
+              move = pick_best(curMove++, lastMove).move;
+              if (   move != ttMoves[0].move
+                  && pos.pl_move_is_legal(move, pinned))
+                  return move;
+              break;
 
-  case PH_BAD_CAPTURES:
-      if (movesPicked < numOfBadCaptures)
-          return badCaptures[movesPicked++].move;
-      break;
+          case PH_QCHECKS:
+              move = (curMove++)->move;
+              if (   move != ttMoves[0].move
+                  && pos.pl_move_is_legal(move, pinned))
+                  return move;
+              break;
 
-  case PH_QCAPTURES:
-  case PH_QCHECKS:
-      while (movesPicked < numOfMoves)
-      {
-          Move move = moves[movesPicked++].move;
-          // Maybe postpone the legality check until after futility pruning?
-          if (   move != ttMove
-              && pos.pl_move_is_legal(move, pinned))
-              return move;
-      }
-      break;
+          case PH_STOP:
+              return MOVE_NONE;
 
-  default:
-      break;
+          default:
+              assert(false);
+              break;
+          }
+      }
+      go_next_phase();
   }
-  return MOVE_NONE;
 }
 
+/// A variant of get_next_move() which takes a lock as a parameter, used to
+/// prevent multiple threads from picking the same move at a split point.
+
+Move MovePicker::get_next_move(Lock &lock) {
+
+   lock_grab(&lock);
+   if (finished)
+   {
+       lock_release(&lock);
+       return MOVE_NONE;
+   }
+   Move m = get_next_move();
+   if (m == MOVE_NONE)
+       finished = true;
 
-/// MovePicker::init_phase_table() initializes the PhaseTable[],
-/// MainSearchPhaseIndex, EvasionPhaseIndex, QsearchWithChecksPhaseIndex
-/// and QsearchWithoutChecksPhaseIndex. It is only called once during
-/// program startup, and never again while the program is running.
-
-void MovePicker::init_phase_table() {
-
-  int i = 0;
-
-  // Main search
-  MainSearchPhaseIndex = i - 1;
-  PhaseTable[i++] = PH_TT_MOVE;
-  PhaseTable[i++] = PH_MATE_KILLER;
-  PhaseTable[i++] = PH_GOOD_CAPTURES;
-  PhaseTable[i++] = PH_KILLERS;
-  PhaseTable[i++] = PH_NONCAPTURES;
-  PhaseTable[i++] = PH_BAD_CAPTURES;
-  PhaseTable[i++] = PH_STOP;
-
-  // Check evasions
-  EvasionsPhaseIndex = i - 1;
-  PhaseTable[i++] = PH_EVASIONS;
-  PhaseTable[i++] = PH_STOP;
-
-  // Quiescence search with checks
-  QsearchWithChecksPhaseIndex = i - 1;
-  PhaseTable[i++] = PH_TT_MOVE;
-  PhaseTable[i++] = PH_QCAPTURES;
-  PhaseTable[i++] = PH_QCHECKS;
-  PhaseTable[i++] = PH_STOP;
-
-  // Quiescence search without checks
-  QsearchWithoutChecksPhaseIndex = i - 1;
-  PhaseTable[i++] = PH_TT_MOVE;
-  PhaseTable[i++] = PH_QCAPTURES;
-  PhaseTable[i++] = PH_STOP;
+   lock_release(&lock);
+   return m;
 }