计算代码执行的CPU时钟

// VS 6.0
#define RDTSC _asm _emit 0x0f _asm _emit 0x31
#pragma warning (push)
#pragma warning (disable:4035)
__inline unsigned __int64 timetested() { RDTSC }
#pragma warning (pop)

// VS.NET 2003
__inline unsigned __int64 timetested()
{
    __asm
    {
        _emit 0x0f
        _emit 0x31
    }
}