Function CAS

benchmarks/tbb/spin_rw_mutex.cpp:34–38

a template can work with private spin_rw_mutex::state_t

template<typename T> // a template can work with private spin_rw_mutex::state_t
static inline T CAS(volatile T &addr, T newv, T oldv) {
    // ICC (9.1 and 10.1 tried) unable to do implicit conversion
    // from "volatile T*" to "volatile void*", so explicit cast added.
    return tbb::internal::as_atomic(addr).compare_and_swap( newv, oldv );
}

//! Acquire write lock on the given mutex.
bool spin_rw_mutex_v3::internal_acquire_writer()