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与上一代CPU比较,从一般用户的角度看,Pentium(奔腾,又称为P5)性能的提高表现在如下四个方面:提高时钟频率、加大字长、增大及改善内部高速缓存性能、采用超标量技术.按照时钟频率为多少MHz,Pentium芯片分别称为Pen-tium 75、90、100、120、133、150、166、180和200.Pentium 200由于频率较高,必须用专用的主板才能安装.Pentium内部算述逻辑运算的字长仍为32位,而访问存储器的字长则增加到64位,这使得Pentium能够更快地更新其内部高速缓冲区的内容.Pentium分别为指令和数据各自提供一个8K的高速缓存,这使得CPU在芯片内部可以同时取指令和取数据,提高了指令的执行速度.另外,Pentium的高速缓存还增加了“回字”的功能.回写是指这样一种技术:当CPU要将数据写入内存时,它可以将数据暂时写入内部高速缓存中,等到必要时才将数据成批写入内存中.当然,CPU必须有一套线路判断并决定何时将高速缓存中的数据写入内存.486芯片的高速缓存执行的是“通写”操作,当CPU要向内存写入数据时,它将数据同时写入高速缓存和内存中,写操作等于没有缓存.
Compared with the previous generation of CPU, Pentium (Pentium, also known as P5) performance from the perspective of the general user in the performance of the following four aspects: increase the clock frequency, increase word length, increase and improve the internal cache performance, using According to the clock frequency for how many MHz, Pentium chips are called Pen-tium 75,90,100,120,133,150,166,180 and 200. Pentium 200 due to higher frequency, you must use a dedicated motherboard to Installed.Pentium internal arithmetic logic is still 32-bit word length, and access to the memory word length increased to 64 bits, which allows the Pentium to update its internal cache faster content.Pentium instructions and data Each providing an 8K cache, which allows the CPU to take instructions and fetch data at the same time inside the chip, improving the execution speed of the instructions. In addition, the Pentium cache also adds the function of “back word”. One technique: When a CPU writes data to memory, it temporarily writes the data to the internal cache and writes the data into memory in batches, if necessary. Of course, the CPU must have a set of lines to determine When the cache data will be written to memory .486 chip cache performs a “write-through” operation, when the CPU to write data to the memory, it will write data into both the cache and memory, write The operation is equal to no cache.