On July 26, 2021, RISC-V has become synonymous with domestic chips in many advertising scenarios, but we have to be careful with some of the concept marketing. The term “home chip” is quite popular, but even when it comes to “home chip”, each company has its own opinions.
RISC-V has become synonymous with domestic chips in many advertising scenarios, but some manufacturers are not expected to use RISC-V to use RISC-V. If you only use RISC-V to do something likeair conditionerremote control,TVThe “home chip”, like the remote control, is not really the rise of the “home chip”.
Huami launched a new generation of Huangshan 2S dual-core RISC-V architecture portable chip at this month’s press conference. In the digital field, Arm and X86 architecture chip products often appear in our field of view, such as Qualcomm’s Snapdragon 888 (Arm architecture),HuaweiKirin 9000 (arm architecture),IntelYAMDMost CPUs (X86 architecture). So what kind of architecture is the RISC-V architecture adopted by the Huangshan 2S released this time? Can RISC-V become China’s hope for overtaking corners?
Instruction set and microarchitecture
The first question, what is the instruction set?
The instruction set is the communication bridge between the software and the hardware. For the CPU, the software must be translated into “machine code” if it is to be executed on the CPU, and the normative standard in this translation process is the instruction set.
For example, it’s like the red and white console game “Super Mario” that we played back then. When we play this game, we need to use the handle to operate the character “Mario” in the game to perform a series of actions, such as “jump”. When we press the “B” button on the handle, the game character will jump.
So, press the “B” key = jump, this is a “command”. There are other keys corresponding to different operations, such as “left” key = move left, “right” key = move right. These are instructions, and the specifications and standards for these instructions are packaged together to form a collection, which is called an instruction set.
The second question is, what is a microarchitecture?
Microarchitecture or microarchitecture design refers to architecture at the integrated circuit level. Simply put, after determining the instruction set, how to design the relevant CPU core?
After that, the CPU design was refined according to the microarchitecture, and after the output and packaging steps, the specific CPU product was finally released.
Note: nowmobile phoneMost CPUs use multi-core designs and different cores on the same CPU can use different microarchitectures.
RISC-V is open source, but should it be free?
Before officially explaining RISC-V, the question of whether or not it charges should be of concern to many people, even saying that this determines whether RISC-V can become the hope of China’s chip corner overtaking.
So do you charge a fee?
Some receive, some don’t.
* Green grid means free
* Yellow box means authorization is required, which can be used for a fee.
* The red grid represents the closed mode, and you can basically buy the final chip product or the device equipped with the corresponding chip.
RISC-V is open source and its instruction set is free. But the microarchitecture that is further developed based on the free instruction set can be loaded.
Reduced instruction set and complex instruction set
The current main instruction set can be divided into two fields, the simplified instruction set represented by the ARM and RISC-V instruction set, and the complex instruction set represented by the X86 instruction set.
Compared to the complex instruction set, the most important feature of the reduced instruction set is that it splits the instructions. Take the “Big Jump” action in the cs (counter-strike) game series as an example.
“Counter Strike: Origins”
Counter-Strike (Counter-Strike) is a first person shooter game. If we need to scale a box in the game, we generally need a “big jump” action to achieve it.
For the simplified set of instructions, to perform the “big jump” action, you must press “squat”, “jump” and an arrow key (forward, backward, left, and right). For a complex set of instructions, the big jump is an instruction. In many cases, the simplified instruction set disassembles the instructions from the complex instruction set. At first glance, it appears that the reduced instruction set is more complicated than the complex instruction set.
In a complex instruction set, although there are many different instructions, many of the basic parts of these instructions are the same. It can be understood that the reduced instruction set selects the same parts of these instructions to form the instruction set, so that the instruction set will be greatly simplified. There are many types of “big leap” actions in CS games, and players will create new “actions” over time. Then every time an action is created, a new “instruction” is added, which obviously makes this “instruction library”. But what if only each key is used as a basic command? There are only dozens of them on the keyboard.
As for whether RISC-V can become the hope of China’s chip overtaking in the curves, I have the following opinions, which I will share with you.
1. RISC-V is open source, but some parts can be sold as commodities. From a localization perspective, if you only use the RISC-V instruction set to develop products, no problem, but if you use products like the RISC-V microarchitecture developed by an American company, these kinds of things may be subject to the US export controls
2. The ecology of RISC-V is currently not as good as ARM and X86, but it is still much better than building an instruction set yourself.
3. Due to its open source function, RISC-V can be used as the backbone of future localized chips. It is no exaggeration to say that it is the hope of Chinese chips to overtake in the curves. But keep in mind that this is an opportunity to compete on the same stage, not an advantage. At present, many foreign chip companies have implemented RISC-V. If there is an American company BRM (name of the overhead company, which means the next ARM) in the future, it will monopolize the RISC-V microarchitecture authorization, and many Chinese If it develops its own “home chip” based on its architecture , the key technology of domestic chips is still restricted by others.
4. You must be careful with conceptual marketing. The term “home chip” is quite popular, but even when it comes to “home chip”, each company has its own opinions. RISC-V has become synonymous with domestic chips in many advertising scenarios, but some manufacturers are not expected to use RISC-V to use RISC-V. If you only use RISC-V to make some “home chips” like air conditioning remotes and TV remotes, this is not really the rise of “home chips”.
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