利用PC机的硬件定时8253, 编制秒表延时(0~9秒)程序.要求: 按任意键,开始计时, 在屏幕上以1秒间隔从0到9显示 按ESC键,计时停止.-use of PC hardware-timed 8253, the establishment of a stopwatch Delay (0 ~ 9 seconds) program. Requirements : by the arbitrary button, the timer on screen to a second interval from 0 to 9 shows by the ESC key, a time to stop.