根据维基百科,x86是CISC设计,但我也听说过/它是RISC。什么是正确的?我还想知道为什么它是CISC或RISC。什么决定设计是RISC还是CISC?是只是微处理器具有的机器语言指令的数量还是有任何其他决定架构的特性?
答案 0 :(得分:45)
x86是CISC架构。指令数量是一个重要因素,因为所有cisc架构都有更多指令。此外,由于指令在cisc中很复杂,所以它们可以在> 1个周期内完成,而在RISC中它们应该是单周期。主要区别在于:
+------------------------------+------------------------------+ | CISC | RISC | +------------------------------+------------------------------+ | Emphasis on hardware | Emphasis on software | | . | | | Includes multi-clock | Single-clock, | | complex instructions | reduced instruction only | | . | | | Memory-to-memory: | Register to register: | | "LOAD" and "STORE" | "LOAD" and "STORE" | | incorporated in instruction | are independent instructions | | . | | | Small code sizes, | Low cycles per second, | | high cycles per second | large code sizes | | . | | | Transistors used for storing | Spends more transistors | | complex instructions | on memory registers | +------------------------------+------------------------------+
有关进一步研究,请参阅此处: http://www-cs-faculty.stanford.edu/~eroberts/courses/soco/projects/risc/risccisc/
答案 1 :(得分:31)