interlockedCompareExchange

最新推荐文章于 2025-10-19 22:31:01 发布

转载最新推荐文章于 2025-10-19 22:31:01 发布 · 1.5k 阅读

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本文深入探讨了原子操作的实现原理，通过C++内联汇编展示了比较并交换指令的具体用法，以及如何利用这些原语来实现锁的获取与释放，确保多线程环境下的数据一致性。

class Lock
{
    volatile int dest = 0;
    int exchange = 100;
    int compare = 0;
    void acquire()
    {
        While(true)
        {
            if(interlockedCompareExchange(&dest, exchange, compare) == 0)
            {
                // lock acquired 
                break;
            }
        }
    }
    // release the lock
    Void release()
    {
        // lock released 
       dest = 0; 
    }
    };

}

inline int _Compare_exchange_seq_cst_8(volatile _Uint8_t *_Tgt, _Uint8_t *_Exp, _Uint8_t _Value) { /* compare and exchange values atomically with sequentially consistent memory order */ _Uint8_t _Old_exp = *_Exp; /* read before atomic operation */

_Uint8_t _Prev = _INTRIN_SEQ_CST(_InterlockedCompareExchange64)((volatile _LONGLONG *)_Tgt, _Value, _Old_exp);

if (_Prev == _Old_exp) return (1); else { /* copy old value */ *_Exp = _Prev; return (0); } }