assert(!is_check());
// Back up the information necessary to undo the null move to the supplied
- // StateInfo object. In the case of a null move, the only thing we need to
- // remember is the en passant square.
+ // StateInfo object.
// Note that differently from normal case here backupSt is actually used as
// a backup storage not as a new state to be used.
backupSt.epSquare = st->epSquare;
+ backupSt.key = st->key;
+ backupSt.mgValue = st->mgValue;
+ backupSt.egValue = st->egValue;
backupSt.previous = st->previous;
st->previous = &backupSt;
// Restore information from the our backup StateInfo object
st->epSquare = st->previous->epSquare;
+ st->key = st->previous->key;
+ st->mgValue = st->previous->mgValue;
+ st->egValue = st->previous->egValue;
st->previous = st->previous->previous;
- if (st->epSquare != SQ_NONE)
- st->key ^= zobEp[st->epSquare];
-
// Update the necessary information
sideToMove = opposite_color(sideToMove);
st->rule50--;
gamePly--;
- st->key ^= zobSideToMove;
-
- st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}