冯 诺依曼结构体系（Von Neumann structure system）.docVIP

冯 诺依曼结构体系（Von Neumann structure system） Von Neumann structure The first computer machines only had fixed purpose programs. The concept of stored program computers has changed all this. The machine is more flexible by creating a set of instruction sets and converting the so-called operations into the execution details of a string of instructions. By using instructions as a special type of static data, a stored program computer can easily change its program and change its contents under program control. Von Neumann structures and stored program computers are common terms. Storing a program concept also allows the program to modify the contents of the program itself when it is executed. One of the design motivations of this concept is the memory location that allows the program to add content itself or change the instructions of the program, as early design requires the user to manually modify it. But as index registers and indirect location access become necessary mechanisms for hardware architecture, this functionality is less important than ever. The feature of program self modification has also been abandoned by modern programming, because it can make understanding and debugging difficult, and the pipeline and cache mechanism of modern CPU will reduce the efficiency of this function. Overall, the concept of the instruction as data makes the combination of language, compiler and other automatic programming tools can be realized; can use the automatic programming program programming [1] to human understanding easily; from the local perspective, emphasis on I/O machines, such as Bitblt, you want to modify the picture pattern the past is that if there is no customized hardware do not. But then it shows that these functions can be effectively achieved by the compile in execution technique. This structure is, of course, flawed, and in addition to the von Neumann bottleneck that will be described below, modifying the program is likely to be very damaging, regardless of in