PCB_SINGLE_STEP
td->td_pcb->pcb_flags |= PCB_SINGLE_STEP;
td->td_pcb->pcb_flags |= PCB_SINGLE_STEP;
if ((td->td_pcb->pcb_flags & PCB_SINGLE_STEP) != 0) {
td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
td->td_pcb->pcb_flags |= PCB_SINGLE_STEP;
if ((td->td_pcb->pcb_flags & PCB_SINGLE_STEP) != 0) {
td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
td->td_pcb->pcb_flags |= PCB_SINGLE_STEP;
td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;