精确计时：纳秒

//纳秒__int64 Count(void){_asm _emit 0x0F_asm _emit 0x31}CWinApp theApp;using namespace std;int _tmain(int argc, TCHAR* argv[], TCHAR* envp[]){int nRetCode = 0;// 初始化 MFC 并在失败时显示错误if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0)){// TODO: 更改错误代码以符合您的需要_tprintf(_T("致命错误: MFC 初始化失败/n"));nRetCode = 1;}else{// TODO: 在此处为应用程序的行为编写代码。}int n1 = Count();int n2 = GetTickCount();for (int i=0;i<5;i++){printf("<timeVal-1> %d/n",Count() - n1);n1 = Count();printf("<timeVal-2> %d/n",GetTickCount()-n2);n2 = GetTickCount();}//for (int i=0;i<5;i++)//{//printf("<timeVal-2> %d/n",GetTickCount()-n2);//n2 = GetTickCount();//}system("pause");return nRetCode;}