x86_atomic_clearbits_u64
x86_atomic_clearbits_u64(&ci->ci_ipending, (1UL << ih->ih_slot));
#define pmap_pte_clearbits(p, b) x86_atomic_clearbits_u64(p, b)
#define x86_atomic_clearbits_ul x86_atomic_clearbits_u64