PG_ASID_MASK
(tlb.tlb_hi & PG_ASID_MASK) != (pid << PG_ASID_SHIFT))
asid = (tlb.tlb_hi & PG_ASID_MASK) >> PG_ASID_SHIFT;
va = tlb.tlb_hi & ~((vaddr_t)PG_ASID_MASK);