log2_to_int_t
step = log2_to_int_t(unsigned int, step_lg2);
#define log2_to_int(a_lg2) log2_to_int_t(pt_vaddr_t, a_lg2)
#define oalog2_to_int(a_lg2) log2_to_int_t(pt_oaddr_t, a_lg2)
static_assert(log2_to_int_t(unsigned int, 0) == 1);
#define log2_to_max_int_t(type, a_lg2) ((type)(log2_to_int_t(type, a_lg2) - 1))