atomic_swap_ulong
(void) atomic_swap_ulong((unsigned long *)&bufsize,
(void) atomic_swap_ulong((unsigned long *)&bufsize,
work_flags = atomic_swap_ulong(&pwp->work_flags, 0);
put = atomic_swap_ulong(putp, 0);
extern ulong_t atomic_swap_ulong(volatile ulong_t *, ulong_t);
__ATOMIC_OPXX(atomic_swap_ulong, ulong_t, "xchg" SUF_LONG, "r")