assert(d > DEPTH_ZERO);
stage = pos.checkers() ? EVASION_TT : MAIN_TT;
- ttMove = pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
+ ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
stage += (ttMove == MOVE_NONE);
}
assert(d <= DEPTH_ZERO);
stage = pos.checkers() ? EVASION_TT : QSEARCH_TT;
- ttMove = pos.pseudo_legal(ttm)
- && (depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare) ? ttm : MOVE_NONE;
+ ttMove = ttm
+ && pos.pseudo_legal(ttm)
+ && (depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare) ? ttm : MOVE_NONE;
stage += (ttMove == MOVE_NONE);
}
assert(!pos.checkers());
stage = PROBCUT_TT;
- ttMove = pos.pseudo_legal(ttm)
+ ttMove = ttm
+ && pos.pseudo_legal(ttm)
&& pos.capture(ttm)
&& pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE;
stage += (ttMove == MOVE_NONE);
/* fallthrough */
case REFUTATION:
- if (select<Next>([&](){ return !pos.capture(move)
+ if (select<Next>([&](){ return move != MOVE_NONE
+ && !pos.capture(move)
&& pos.pseudo_legal(move); }))
return move;
++stage;
/// Position::pseudo_legal() takes a random move and tests whether the move is
/// pseudo legal. It is used to validate moves from TT that can be corrupted
/// due to SMP concurrent access or hash position key aliasing.
-/// MOVE_NONE is represented as SQ_A1 to SQ_A1 which is never pseudo_legal.
bool Position::pseudo_legal(const Move m) const {