/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, 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
STOP
};
- // Our insertion sort, which is guaranteed (and also needed) to be stable
+ // Our insertion sort, which is guaranteed to be stable, as it should be
void insertion_sort(ExtMove* begin, ExtMove* end)
{
ExtMove tmp, *p, *q;
}
}
- // Unary predicate used by std::partition to split positive values from remaining
- // ones so as to sort the two sets separately, with the second sort delayed.
- inline bool has_positive_value(const ExtMove& ms) { return ms.value > 0; }
-
- // Picks the best move in the range (begin, end) and moves it to the front.
- // It's faster than sorting all the moves in advance when there are few
- // moves e.g. possible captures.
- inline ExtMove* pick_best(ExtMove* begin, ExtMove* end)
+ // pick_best() finds the best move in the range (begin, end) and moves it to
+ // the front. It's faster than sorting all the moves in advance when there
+ // are few moves e.g. the possible captures.
+ inline Move pick_best(ExtMove* begin, ExtMove* end)
{
std::swap(*begin, *std::max_element(begin, end));
- return begin;
+ return *begin;
}
+
} // namespace
assert(d > DEPTH_ZERO);
- cur = end = moves;
endBadCaptures = moves + MAX_MOVES - 1;
countermoves = cm;
followupmoves = fm;
stage = MAIN_SEARCH;
ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
- end += (ttMove != MOVE_NONE);
+ endMoves += (ttMove != MOVE_NONE);
}
MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
- Square s) : pos(p), history(h), cur(moves), end(moves) {
+ Square s) : pos(p), history(h) {
assert(d <= DEPTH_ZERO);
stage = QSEARCH_0;
else if (d > DEPTH_QS_RECAPTURES)
- {
stage = QSEARCH_1;
- // Skip TT move if is not a capture or a promotion. This avoids qsearch
- // tree explosion due to a possible perpetual check or similar rare cases
- // when TT table is full.
- if (ttm && !pos.capture_or_promotion(ttm))
- ttm = MOVE_NONE;
- }
else
{
stage = RECAPTURE;
}
ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
- end += (ttMove != MOVE_NONE);
+ endMoves += (ttMove != MOVE_NONE);
}
MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, PieceType pt)
- : pos(p), history(h), cur(moves), end(moves) {
+ : pos(p), history(h) {
assert(!pos.checkers());
if (ttMove && (!pos.capture(ttMove) || pos.see(ttMove) <= captureThreshold))
ttMove = MOVE_NONE;
- end += (ttMove != MOVE_NONE);
+ endMoves += (ttMove != MOVE_NONE);
}
// badCaptures[] array, but instead of doing it now we delay until the move
// has been picked up in pick_move_from_list(). This way we save some SEE
// calls in case we get a cutoff.
- Move m;
-
- for (ExtMove* it = moves; it != end; ++it)
- {
- m = it->move;
- it->value = PieceValue[MG][pos.piece_on(to_sq(m))]
- - Value(type_of(pos.moved_piece(m)));
-
+ for (auto& m : *this)
if (type_of(m) == ENPASSANT)
- it->value += PieceValue[MG][PAWN];
+ m.value = PieceValue[MG][PAWN] - Value(PAWN);
else if (type_of(m) == PROMOTION)
- it->value += PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN];
- }
+ m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - Value(PAWN)
+ + PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN];
+ else
+ m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - Value(type_of(pos.moved_piece(m)));
}
template<>
void MovePicker::score<QUIETS>() {
-
- Move m;
-
- for (ExtMove* it = moves; it != end; ++it)
- {
- m = it->move;
- it->value = history[pos.moved_piece(m)][to_sq(m)];
- }
+ for (auto& m : *this)
+ m.value = history[pos.moved_piece(m)][to_sq(m)];
}
template<>
// Try good captures ordered by MVV/LVA, then non-captures if destination square
// is not under attack, ordered by history value, then bad-captures and quiet
// moves with a negative SEE. This last group is ordered by the SEE value.
- Move m;
Value see;
- for (ExtMove* it = moves; it != end; ++it)
- {
- m = it->move;
+ for (auto& m : *this)
if ((see = pos.see_sign(m)) < VALUE_ZERO)
- it->value = see - HistoryStats::Max; // At the bottom
+ m.value = see - HistoryStats::Max; // At the bottom
else if (pos.capture(m))
- it->value = PieceValue[MG][pos.piece_on(to_sq(m))]
- - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max;
+ m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max;
else
- it->value = history[pos.moved_piece(m)][to_sq(m)];
- }
+ m.value = history[pos.moved_piece(m)][to_sq(m)];
}
switch (++stage) {
case CAPTURES_S1: case CAPTURES_S3: case CAPTURES_S4: case CAPTURES_S5: case CAPTURES_S6:
- end = generate<CAPTURES>(pos, moves);
+ endMoves = generate<CAPTURES>(pos, moves);
score<CAPTURES>();
- return;
+ break;
case KILLERS_S1:
cur = killers;
- end = cur + 2;
-
- killers[0].move = ss->killers[0];
- killers[1].move = ss->killers[1];
- killers[2].move = killers[3].move = MOVE_NONE;
- killers[4].move = killers[5].move = MOVE_NONE;
-
- // Please note that following code is racy and could yield to rare (less
- // than 1 out of a million) duplicated entries in SMP case. This is harmless.
-
- // Be sure countermoves are different from killers
- for (int i = 0; i < 2; ++i)
- if ( countermoves[i] != (cur+0)->move
- && countermoves[i] != (cur+1)->move)
- (end++)->move = countermoves[i];
-
- // Be sure followupmoves are different from killers and countermoves
- for (int i = 0; i < 2; ++i)
- if ( followupmoves[i] != (cur+0)->move
- && followupmoves[i] != (cur+1)->move
- && followupmoves[i] != (cur+2)->move
- && followupmoves[i] != (cur+3)->move)
- (end++)->move = followupmoves[i];
- return;
+ endMoves = cur + 6;
+ killers[0] = ss->killers[0];
+ killers[1] = ss->killers[1];
+ killers[2] = countermoves[0];
+ killers[3] = countermoves[1];
+ killers[4] = followupmoves[0];
+ killers[5] = followupmoves[1];
+ break;
case QUIETS_1_S1:
- endQuiets = end = generate<QUIETS>(pos, moves);
+ endQuiets = endMoves = generate<QUIETS>(pos, moves);
score<QUIETS>();
- end = std::partition(cur, end, has_positive_value);
- insertion_sort(cur, end);
- return;
+ endMoves = std::partition(cur, endMoves, [](const ExtMove& m) { return m.value > VALUE_ZERO; });
+ insertion_sort(cur, endMoves);
+ break;
case QUIETS_2_S1:
- cur = end;
- end = endQuiets;
+ cur = endMoves;
+ endMoves = endQuiets;
if (depth >= 3 * ONE_PLY)
- insertion_sort(cur, end);
- return;
+ insertion_sort(cur, endMoves);
+ break;
case BAD_CAPTURES_S1:
// Just pick them in reverse order to get MVV/LVA ordering
cur = moves + MAX_MOVES - 1;
- end = endBadCaptures;
- return;
+ endMoves = endBadCaptures;
+ break;
case EVASIONS_S2:
- end = generate<EVASIONS>(pos, moves);
- if (end > moves + 1)
+ endMoves = generate<EVASIONS>(pos, moves);
+ if (endMoves - moves > 1)
score<EVASIONS>();
- return;
+ break;
case QUIET_CHECKS_S3:
- end = generate<QUIET_CHECKS>(pos, moves);
- return;
+ endMoves = generate<QUIET_CHECKS>(pos, moves);
+ break;
case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE:
stage = STOP;
/* Fall through */
case STOP:
- end = cur + 1; // Avoid another next_phase() call
- return;
+ endMoves = cur + 1; // Avoid another generate_next_stage() call
+ break;
default:
assert(false);
while (true)
{
- while (cur == end)
+ while (cur == endMoves)
generate_next_stage();
switch (stage) {
return ttMove;
case CAPTURES_S1:
- move = pick_best(cur++, end)->move;
+ move = pick_best(cur++, endMoves);
if (move != ttMove)
{
if (pos.see_sign(move) >= VALUE_ZERO)
return move;
// Losing capture, move it to the tail of the array
- (endBadCaptures--)->move = move;
+ *endBadCaptures-- = move;
}
break;
case KILLERS_S1:
- move = (cur++)->move;
+ move = *cur++;
if ( move != MOVE_NONE
&& move != ttMove
&& pos.pseudo_legal(move)
&& !pos.capture(move))
+ {
+ for (int i = 0; i < cur - 1 - killers; i++) // Skip duplicated
+ if (move == killers[i])
+ goto skip;
return move;
+ }
+ skip:
break;
case QUIETS_1_S1: case QUIETS_2_S1:
- move = (cur++)->move;
+ move = *cur++;
if ( move != ttMove
- && move != killers[0].move
- && move != killers[1].move
- && move != killers[2].move
- && move != killers[3].move
- && move != killers[4].move
- && move != killers[5].move)
+ && move != killers[0]
+ && move != killers[1]
+ && move != killers[2]
+ && move != killers[3]
+ && move != killers[4]
+ && move != killers[5])
return move;
break;
case BAD_CAPTURES_S1:
- return (cur--)->move;
+ return *cur--;
case EVASIONS_S2: case CAPTURES_S3: case CAPTURES_S4:
- move = pick_best(cur++, end)->move;
+ move = pick_best(cur++, endMoves);
if (move != ttMove)
return move;
break;
case CAPTURES_S5:
- move = pick_best(cur++, end)->move;
+ move = pick_best(cur++, endMoves);
if (move != ttMove && pos.see(move) > captureThreshold)
return move;
break;
case CAPTURES_S6:
- move = pick_best(cur++, end)->move;
+ move = pick_best(cur++, endMoves);
if (to_sq(move) == recaptureSquare)
return move;
break;
case QUIET_CHECKS_S3:
- move = (cur++)->move;
+ move = *cur++;
if (move != ttMove)
return move;
break;
projects / stockfish / blobdiff