casuword32
(void)casuword32(args->uaddr, owner, old_owner);
owner = casuword32(m, UMUTEX_UNOWNED, id);
owner = casuword32(m,
old = casuword32(m, owner, owner | UMUTEX_CONTESTED);
old = casuword32(m, owner, UMUTEX_UNOWNED);
old = casuword32(m, owner,
(void)casuword32(&m->m_owner,
uint32_t casuword32(volatile uint32_t *base, uint32_t oldval, uint32_t newval);