int MvvLva(POS *p, int move) {
// Captures
if (p->pc[Tsq(move)] != NO_PC)
return TpOnSq(p, Tsq(move)) * 6 + 5 - TpOnSq(p, Fsq(move));
// Non-capturing promotions
if (IsProm(move)) return PromType(move) - 5;
return 5;
}
void UpdateHistory(POS *p, int last_move, int move, int depth, int ply) {
// Don't update stuff used for move ordering if a move changes material balance
if (p->pc[Tsq(move)] != NO_PC || IsProm(move) || MoveType(move) == EP_CAP)
return;
// Asserts suggested by Ferdinand Mosca because history[] would overflow
// if p->pc[Fsq(move)] == NO_PC. If they ever fire, either move or board
// data are corrupt.
assert(p->pc[Fsq(move)] != NO_PC); // To detect no_pc
assert(p->pc[Fsq(move)] <= NO_PC); // To detect beyond no_pc for deeper examination
// Increment history counter
history[p->pc[Fsq(move)]][Tsq(move)] += 2 * depth * depth;
// Prevent history counters from growing too high
if (history[p->pc[Fsq(move)]][Tsq(move)] > HIST_LIMIT)
TrimHistory();
// Update refutation table, saving new move in the table indexed
// by the coordinates of last move. last_move == 0 is a null move,
// special case of last_move == -1 denotes situations when updating
// refutation table is switched off: at root or in QuiesceFlee()
if (last_move >= 0)
refutation[Fsq(last_move)][Tsq(last_move)] = move;
// Update killer moves, taking care that they are different
if (move != killer[ply][0]) {
killer[ply][1] = killer[ply][0];
killer[ply][0] = move;
}
}
int sHistory::MoveChangesMaterialBalance(sPosition *p, int move)
{
if (p->pc[Tsq(move)] != NO_PC || IsProm(move) || MoveType(move) == EP_CAP) return 1;
return 0;
}
