}
                mtx_unlock_spin(&sc->sc_lock);
  974808:       7f dc ea 14     add     r30,r28,r29
  97480c:       80 7e 00 14     lwz     r3,20(r30)
  974810:       28 03 00 00     cmplwi  r3,0
  974814:       41 82 00 10     beq-    974824 <sleepq_switch+0x198>
  974818:       38 63 ff ff     addi    r3,r3,-1
  -------->  97481c:       90 7e 00 14     stw     r3,20(r30) <--------- PREEMPTED HERE
  974820:       48 00 00 24     b       974844 <sleepq_switch+0x1b8>
  974824:       3c 62 ff c6     addis   r3,r2,-58
  974828:       38 63 c0 3a     addi    r3,r3,-16326
  97482c:       88 63 00 00     lbz     r3,0(r3)
  974830:       28 03 00 00     cmplwi  r3,0
  974834:       40 82 00 d0     bne-    974904 <sleepq_switch+0x278>
  974838:       38 60 00 00     li      r3,0
  97483c:       7c 20 04 ac     lwsync
  974840:       f8 7e 00 20     std     r3,32(r30)
  974844:       48 41 d6 5d     bl      d91ea0 <spinlock_exit+0x8>
  974848:       60 00 00 00     nop
        TD_SET_SLEEPING(td);
        mi_switch(SW_VOL | SWT_SLEEPQ, NULL);
        KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING"));
        CTR3(KTR_PROC, "sleepq resume: thread %p (pid %ld, %s)",
            (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name);