GCC 之 cas和cas2

cas.h

#if defined(__GNUC__)

#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP)
#define CAS  __sync_bool_compare_and_swap
#endif

//CAS2
#if defined(__x86_64__)

#if  defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_16)
#define CAS2(p,o,n)  __sync_bool_compare_and_swap_16((long long *)(p), *(long long *)(&o), *(long long *)(&n))
#else
#define CAS2(p,o,n)  CAS2_IMPL((long long *)(p), (long *)(&o), (long *)(&n))
inline
bool CAS2_IMPL(long *addr,
        long * old_value,
        long * new_value)
{
    bool  ret;
    __asm__ __volatile__(
            "lock cmpxchg16b %1;\n"
            "sete %0;\n"
            :"=m"(ret),"+m" (*(volatile long long *) (addr))
            :"a" (old_value[0]), "d" (old_value[1]), "b" (new_value[0]), "c" (new_value[1]));
    return ret;
}
#endif

#else
#if !defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
#define CAS2(p,o,n)  __sync_bool_compare_and_swap_8((long long *)(p), *(long long *)(&o), *(long long *)(&n))
#else
#define CAS2(p,o,n)  CAS2_IMPL((long long *)(p), (long *)(&o), (long *)(&n))
inline
bool CAS2_IMPL(long long *addr,
        long * old_value,
        long * new_value)
{
    bool  ret;
    __asm__ __volatile__(
            "lock cmpxchg8b %1;\n"
            "sete %0;\n"
            :"=m"(ret),"+m" (*(volatile long long *) (addr))
            :"a" (old_value[0]), "d" (old_value[1]), "b" (new_value[0]), "c" (new_value[1]));
    return ret;
}

#endif

#endif //CAS2

#endif //__GNUC__