atf_swap
atf_swap(atomic_swap_32, uint32_t, "0x%" PRIx32);
atf_swap(atomic_swap_uint, unsigned int, "0x%x");
atf_swap(atomic_swap_ulong, unsigned long, "0x%lx");
atf_swap(atomic_swap_ptr, void *, "%p");
atf_swap(atomic_swap_64, uint64_t, "0x%" PRIx64);