static int extract_ponder_from_tt(RootMove *rm, Pos *pos)
{
int ttHit;
assert(rm->pvSize == 1);
if (!rm->pv[0])
return 0;
do_move(pos, rm->pv[0], gives_check(pos, pos->st, rm->pv[0]));
TTEntry *tte = tt_probe(pos_key(), &ttHit);
if (ttHit) {
Move m = tte_move(tte); // Local copy to be SMP safe
ExtMove list[MAX_MOVES];
ExtMove *last = generate_legal(pos, list);
for (ExtMove *p = list; p < last; p++)
if (p->move == m) {
rm->pv[rm->pvSize++] = m;
break;
}
}
undo_move(pos, rm->pv[0]);
return rm->pvSize > 1;
}
static bool check_draw(Pos *pos, Move m)
{
do_move(pos, m, gives_check(pos, pos->st, m));
bool draw = is_draw(pos); // 64
undo_move(pos, m);
return draw;
}
static uint64_t perft_helper(Pos *pos, Depth depth, uint64_t nodes)
{
ExtMove *m = (pos->st-1)->endMoves;
ExtMove *last = pos->st->endMoves = generate_legal(pos, m);
for (; m < last; m++) {
do_move(pos, m->move, gives_check(pos, pos->st, m->move));
if (depth == 0) {
nodes += generate_legal(pos, last) - last;
} else
nodes = perft_helper(pos, depth - ONE_PLY, nodes);
undo_move(pos, m->move);
}
return nodes;
}
uint64_t perft(Pos *pos, Depth depth)
{
uint64_t cnt, nodes = 0;
char buf[16];
ExtMove *m = pos->moveList;
ExtMove *last = pos->st->endMoves = generate_legal(pos, m);
for (; m < last; m++) {
if (depth <= ONE_PLY) {
cnt = 1;
nodes++;
} else {
do_move(pos, m->move, gives_check(pos, pos->st, m->move));
if (depth == 2 * ONE_PLY)
cnt = generate_legal(pos, last) - last;
else
cnt = perft_helper(pos, depth - 3 * ONE_PLY, 0);
nodes += cnt;
undo_move(pos, m->move);
}
printf("%s: %"PRIu64"\n", uci_move(buf, m->move, is_chess960()), cnt);
}
return nodes;
}
Value name_NT_InCheck(qsearch)(Pos* pos, Stack* ss, Value alpha, BETA_ARG
Depth depth)
{
assert(InCheck == !!pos_checkers());
assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
assert(PvNode || (alpha == beta - 1));
assert(depth <= DEPTH_ZERO);
Move pv[MAX_PLY+1];
TTEntry *tte;
Key posKey;
Move ttMove, move, bestMove;
Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
int ttHit, ttPv, givesCheck, evasionPrunable;
Depth ttDepth;
int moveCount;
if (PvNode) {
oldAlpha = alpha; // To flag BOUND_EXACT when eval above alpha and no available moves
(ss+1)->pv = pv;
ss->pv[0] = 0;
}
bestMove = 0;
moveCount = 0;
// Check for an instant draw or if the maximum ply has been reached
if (is_draw(pos) || ss->ply >= MAX_PLY)
return ss->ply >= MAX_PLY && !InCheck ? evaluate(pos) : VALUE_DRAW;
assert(0 <= ss->ply && ss->ply < MAX_PLY);
// Decide whether or not to include checks: this fixes also the type of
// TT entry depth that we are going to use. Note that in qsearch we use
// only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
: DEPTH_QS_NO_CHECKS;
// Transposition table lookup
posKey = pos_key();
tte = tt_probe(posKey, &ttHit);
ttValue = ttHit ? value_from_tt(tte_value(tte), ss->ply) : VALUE_NONE;
ttMove = ttHit ? tte_move(tte) : 0;
ttPv = ttHit ? tte_is_pv(tte) : 0;
if ( !PvNode
&& ttHit
&& tte_depth(tte) >= ttDepth
&& ttValue != VALUE_NONE // Only in case of TT access race
&& (ttValue >= beta ? (tte_bound(tte) & BOUND_LOWER)
: (tte_bound(tte) & BOUND_UPPER)))
return ttValue;
// Evaluate the position statically
if (InCheck) {
ss->staticEval = VALUE_NONE;
bestValue = futilityBase = -VALUE_INFINITE;
} else {
if (ttHit) {
// Never assume anything on values stored in TT
if ((ss->staticEval = bestValue = tte_eval(tte)) == VALUE_NONE)
ss->staticEval = bestValue = evaluate(pos);
// Can ttValue be used as a better position evaluation?
if (ttValue != VALUE_NONE)
if (tte_bound(tte) & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))
bestValue = ttValue;
} else
ss->staticEval = bestValue =
(ss-1)->currentMove != MOVE_NULL ? evaluate(pos)
: -(ss-1)->staticEval + 2 * Tempo;
// Stand pat. Return immediately if static value is at least beta
if (bestValue >= beta) {
if (!ttHit)
tte_save(tte, posKey, value_to_tt(bestValue, ss->ply), ttPv,
BOUND_LOWER, DEPTH_NONE, 0, ss->staticEval,
tt_generation());
return bestValue;
}
if (PvNode && bestValue > alpha)
alpha = bestValue;
futilityBase = bestValue + 128;
}
ss->history = &(*pos->counterMoveHistory)[0][0];
// Initialize move picker data for the current position, and prepare
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
// be generated.
mp_init_q(pos, ttMove, depth, to_sq((ss-1)->currentMove));
// Loop through the moves until no moves remain or a beta cutoff occurs
while ((move = next_move(pos, 0))) {
assert(move_is_ok(move));
givesCheck = gives_check(pos, ss, move);
moveCount++;
// Futility pruning
if ( !InCheck
&& !givesCheck
&& futilityBase > -VALUE_KNOWN_WIN
&& !advanced_pawn_push(pos, move)) {
assert(type_of_m(move) != ENPASSANT); // Due to !advanced_pawn_push
futilityValue = futilityBase + PieceValue[EG][piece_on(to_sq(move))];
if (futilityValue <= alpha) {
bestValue = max(bestValue, futilityValue);
continue;
}
if (futilityBase <= alpha && !see_test(pos, move, 1)) {
bestValue = max(bestValue, futilityBase);
continue;
}
}
// Detect non-capture evasions that are candidates to be pruned
evasionPrunable = InCheck
&& (depth != DEPTH_ZERO || moveCount > 2)
&& bestValue > VALUE_MATED_IN_MAX_PLY
&& !is_capture(pos, move);
// Don't search moves with negative SEE values
if ( (!InCheck || evasionPrunable)
&& !see_test(pos, move, 0))
continue;
// Speculative prefetch as early as possible
prefetch(tt_first_entry(key_after(pos, move)));
// Check for legality just before making the move
if (!is_legal(pos, move)) {
moveCount--;
continue;
}
ss->currentMove = move;
ss->history = &(*pos->counterMoveHistory)[moved_piece(move)][to_sq(move)];
// Make and search the move
do_move(pos, move, givesCheck);
#if PvNode
value = givesCheck
? -qsearch_PV_true(pos, ss+1, -beta, -alpha, depth - ONE_PLY)
: -qsearch_PV_false(pos, ss+1, -beta, -alpha, depth - ONE_PLY);
#else
value = givesCheck
? -qsearch_NonPV_true(pos, ss+1, -beta, depth - ONE_PLY)
: -qsearch_NonPV_false(pos, ss+1, -beta, depth - ONE_PLY);
#endif
undo_move(pos, move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
// Check for a new best move
if (value > bestValue) {
bestValue = value;
if (value > alpha) {
bestMove = move;
if (PvNode) // Update pv even in fail-high case
update_pv(ss->pv, move, (ss+1)->pv);
if (PvNode && value < beta) // Update alpha here!
alpha = value;
else
break; // Fail high
}
}
}
// All legal moves have been searched. A special case: If we're in check
// and no legal moves were found, it is checkmate.
if (InCheck && bestValue == -VALUE_INFINITE)
return mated_in(ss->ply); // Plies to mate from the root
tte_save(tte, posKey, value_to_tt(bestValue, ss->ply), ttPv,
bestValue >= beta ? BOUND_LOWER :
PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER,
ttDepth, bestMove, ss->staticEval, tt_generation());
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
return bestValue;
}
// 利きのある場所への取れない近接王手からの3手詰め
Move Position::weak_mate_n_ply(int ply) const
{
// 1手詰めであるならこれを返す
Move m = mate1ply();
if (m)
return m;
// 詰まない
if (ply <= 1)
return MOVE_NONE;
Color us = side_to_move();
Color them = ~us;
Bitboard around8 = kingEffect(king_square(them));
// const剥がし
Position* This = ((Position*)this);
StateInfo si;
StateInfo si2;
// 近接王手で味方の利きがあり、敵の利きのない場所を探す。
for (auto m : MoveList<CHECKS>(*this))
{
// 近接王手で、この指し手による駒の移動先に敵の駒がない。
Square to = to_sq(m);
if ((around8 & to)
#ifndef LONG_EFFECT_LIBRARY
// toに利きがあるかどうか。mが移動の指し手の場合、mの元の利きを取り除く必要がある。
&& (is_drop(m) ? effected_to(us, to) : (attackers_to(us, to, pieces() ^ from_sq(m)) ^ from_sq(m)))
// 敵玉の利きは必ずtoにあるのでそれを除いた利きがあるかどうか。
&& (attackers_to(them,to,pieces()) ^ king_square(them))
#else
&& (is_drop(m) ? effected_to(us, to) :
board_effect[us].effect(to) >= 2 ||
(long_effect.directions_of(us, from_sq(m)) & Effect8::directions_of(from_sq(m), to)) != 0)
// 敵玉の利きがあるので2つ以上なければそれで良い。
&& (board_effect[them].effect(to) <= 1)
#endif
)
{
if (!legal(m))
continue;
ASSERT_LV3(gives_check(m));
This->do_move(m,si,true);
ASSERT_LV3(in_check());
// この局面ですべてのevasionを試す
for (auto m2 : MoveList<EVASIONS>(*this))
{
if (!legal(m2))
continue;
// この指し手で逆王手になるなら、不詰めとして扱う
if (gives_check(m2))
goto NEXT_CHECK;
This->do_move(m2, si2, false);
ASSERT_LV3(!in_check());
if (!weak_mate_n_ply(ply-2))
{
// 詰んでないので、m2で詰みを逃れている。
This->undo_move(m2);
goto NEXT_CHECK;
}
This->undo_move(m2);
}
// すべて詰んだ
This->undo_move(m);
// mによって3手で詰む。
return m;
NEXT_CHECK:;
This->undo_move(m);
}
}
return MOVE_NONE;
}
