PCB_DBREGS
KASSERT((pcb->pcb_flags & PCB_DBREGS) == 0);
pcb->pcb_flags &= ~PCB_DBREGS;
pcb->pcb_flags &= ~PCB_DBREGS;
pcb->pcb_flags |= PCB_DBREGS;
if (!(pcb->pcb_flags & PCB_DBREGS)) {
if (!(pcb->pcb_flags & PCB_DBREGS)) {
pcb->pcb_flags |= PCB_DBREGS;
olddb = (oldpcb->pcb_flags & PCB_DBREGS) != 0;
newdb = (newpcb->pcb_flags & PCB_DBREGS) != 0;
pcb2->pcb_flags &= ~PCB_DBREGS;
KASSERT((pcb->pcb_flags & PCB_DBREGS) == 0);