I learned the basics of computer friends all know the meaning of CPU, that is the central processing unit, is the main component responsible for computer computing tasks. Generally used to the CPU metaphor human brain. The slightly deeper understanding of users will have heard CPU x86, ARM, etc. and the former while the latter mainly for the PC tablet is mainly used for mobile phones and other devices. So here's x86, ARM refers to what is it?
Need to comply with certain norms in the CPU perform computing tasks, the program is executed before all need to be translated into the language CPU understandable. This is the language specification or instruction set (ISA, Instruction Set Architecture). Underlying code program is translated into recognizable CPU according to a certain instruction set specification process is called to compile (compile). x86, ARM v8, MIPS instruction code are set . It can be extended instruction set, such as support for 64-bit x86 increase there x86-64. Some manufacturers have developed compatible instruction set CPU instruction set require authorization patent holder, such as a typical example of the AMD Intel authorization, so that the latter can develop the x86 instruction set compatible CPU.
It is the basic unit of the CPU core (core). The core can simultaneously execute multiple pieces of computing tasks, provided that these tasks are not listed in sequence.
The core implementation is called micro-architecture (microarchitecture). Micro-architecture design affects the core of the highest frequency that can be achieved, the computational core at a certain frequency that can be executed, and so the core of the energy consumption level under a certain level of technology. In addition, different micro-architecture to perform various types of programs tend to be different, such as the late 1990s Intel's P6 microarchitecture to superior performance on floating-point type program, but not in integer type applications like frequency at opponents.
CPU instruction set is a standardized processing instructions and data, we can only enter the specified format command to operate the computer. And this is for programmers and users levels. The CPU micro-architecture is designed for persons, an instruction execution unit processor design, upon completion of the entire design, architecture microprocessor executes a predetermined instruction set of a composition called "micro-architecture."
Common Code as the title of Haswell, Cortex-A15 are all micro-architecture. Note that micro-architecture and instruction set are two concepts: CPU instruction set is selected language, the microarchitecture of specific implementations. Core i7-4770 is the Haswell microarchitecture, this micro-architecture compatible with the x86 instruction set. For the ARM instruction set compatible chip is easy to confuse the two concepts in particular: ARM company will develop its own instruction set called the ARM instruction set, but it also developed specific micro-architecture such as Cortex family and for licensing. However, a CPU uses the ARM instruction set does not mean that it developed using ARM micro-architecture . Intel, Qualcomm, Apple, Nvidia and other manufacturers have developed their own instruction set compatible ARM micro-architecture, as well as many manufacturers use ARM architecture to the development of micro-manufacturing CPU. In general, the industry believes that only an independent micro-architecture research and development capabilities of enterprises considered have the CPU R & D capabilities, and whether to use self-developed instruction set does not matter . Microarchitecture R & D is one of the highest areas of the IT industry technical content.
Mentioned earlier instruction set is the "norm", which means that he can guide the CPU designers by reading the "instruction set specification," this "guide" to design the CPU. The CPU designers through after reading this specification designed CPU architecture called "micro-architecture." More formally, is the "micro-architecture" is the "instruction set" specific "to achieve." So you can, for example from our daily use, AMD and Intel processors are based on the same x86 instruction set, but they are specific processor micro-architecture is different, this is a typical "realization" problem.
Instruction set and microarchitecture is a different concept, not to be confused; the CPU research and development refers to the development of micro-architecture ; instruction set is now no longer has "the most suitable areas" argument.
Godson CPU-made news a few years ago to get MIPS licensees had caused a storm, Godson responsible person has also come forward and explain. Godson is compatible with the MIPS instruction set, micro-architecture part by the Chinese Academy of Sciences self-developed CPU series . Chinese Academy of Sciences in the past so there is no lack of funds authorized MIPS instruction set, but the implementation of the instruction set is public, so you can choose compatible with the Chinese Academy of Sciences in the development of the instruction set. After sufficient funds to buy authorized, Godson can be legally sold in the market. From here we can see, it does not need to obtain authorization instruction set when manufacturers develop CPU can obtain relevant information and normative instruction set, the instruction set of technical content itself is not very high. Authorized mainly to avoid legal problems. However, micro-architecture design details of various manufacturers is absolutely confidential, and because of its technical complexity, even if it is difficult to obtain the appropriate documentation cottage. Different manufacturers of micro-architecture design level is also quite different, such as the typical comparison of Intel and AMD, the former clearly came out on top in the last few years.
Developed the micro-architecture, or the core research and development is completed, the next step is to assemble it into a chip. The chip includes only the last part of the CPU, and now a large number of chip integrates a variety of different functional components CPU, GPU, IO and so on, this time on the chip "CPU" in the traditional sense is not. The various functional components assembled for the technical content of the chip micro-architecture compared to R & D is low, so the industry can do this type of work is also a larger number of companies.
In the PC era, several major CPU manufacturers have only their own research and development microarchitecture own use. To the smart device era, ARM's licensing model microarchitecture rise. ARM will develop their own micro-architecture them on shelves, other manufacturers can take these core assembly to use or sell the chip. Because of this pattern of technological capabilities of third-party requirements are very low, coupled with ARM micro-architecture with outstanding performance in the field of low power consumption, this model has been widely successful. If you find a section marked using a chip core Cortex family, it must be the product of this model. As mentioned earlier, only buy from ARM microarchitecture to assemble the chip makers can not be called a CPU R & D companies, these chips can not be called "xx vendor-developed CPU." Typical such as Huawei Hass 920, Samsung Exynos 5430, can only be described as "the use of ARM Cortex-A15 core chip." However, if an ARM instruction set compatible chip manufacturers use a self-developed micro-architecture the situation is different. Qualcomm Xiaolong 800, Apple A7 is one such example - they were using Qualcomm, Apple's self-developed CPU.
With the smart device market continues to expand, ARM camp is also growing. After the occupation of intelligent field devices, ARM camp began to enter the PC, server and high-performance computing. First, ARM announced the ARM v8 64-bit instruction set specification, followed by the major manufacturers have begun to develop ARM v8-based high-performance micro-architecture. Some people may ask, ARM instruction set is not a low-power device developed it? How high-performance CPU and now began to do it? Years ago this suspicion is justified, because the impact of a different instruction set that time on the micro-architecture is still relatively large, ARM suitable for low-power, x86 for PC, Power ...... for minicomputers such distinction exists. But as technology advances, the impact on the microarchitecture instruction set has been small enough to be ignored, any instruction set can be made excellent micro-architecture for different fields come. Therefore, the user sees the x86 instruction set cpu phone or server CPU ARM instruction set are not surprising, this is a natural consequence of technological development.
In addition to the industry's x86 and ARM, MIPS, in fact, there are a lot of kinds of instruction set. For example, a host of small areas of Sparc, Alpha, Power and so on.
Place the piece may be outdated, but can also be described with the micro instruction set architectures are different concepts of FIG.
The first uses to purchase a license: the introduction of technology route, IP licensing purchase of foreign CPU, and with the existing ecosystem to develop new markets. Such as Huawei and ZTE Microelectronics Hass unicorn, authorized IP from the chip design company Arm.
The second category using Joint Ventures / Cooperation: 10 years ago, China began to implement technology transfer through joint venture with foreign companies, joint venture there is a benefit that can come into contact with more advanced technology, but there is a downside is likely to depend on foreign technology form can not form their own independent research and development capabilities. ARM, Qualcomm and other companies in mainland China set up a joint venture company, Intel, IBM and other companies also support the agents through technical cooperation.
The third use of independent innovation, and on behalf of Shen Wei is the Godson.
From the perspective of the revolutionary point of view, Shen Wei is more revolutionary than the Godson, Godson, after all, for the eco-compatible MIPS instruction set, MIPS and expanded on the basis of the formation of LoongISA, Shen Wei independent development SW64 command.