while (b)
{
- r |= Us == WHITE ? db[index(pop_1st_bit(&b), bksq, psq, BLACK)]
- : db[index(wksq, pop_1st_bit(&b), psq, WHITE)];
+ r |= Us == WHITE ? db[index(pop_lsb(&b), bksq, psq, BLACK)]
+ : db[index(wksq, pop_lsb(&b), psq, WHITE)];
if (Us == WHITE && (r & WIN))
return WIN;