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1. Short answer questions
1. How to find the first microinstruction corresponding to the instruction?
Answer: Usually, the execution of an instruction always starts with fetching the instruction, and decoding the instruction after fetching the instruction. A dispatch table can be implemented with ROM, whose entry is the instruction decoding result, and the output is the microinstruction sequence corresponding to each instruction. The address of the first uop in the control memory. According to this address, it is enough to fetch the microinstructions on the first day from the control memory (CM) and execute them.
2. Briefly describe the working principle of Cache.
Answer: The data exchange between CPU and Cache is based on words, while the data exchange between Cache and main memory is based on blocks. A block consists of several characters and is of fixed length.
When the CPU reads a word in memory, it sends the memory address of the word to Cache and main memory. At this time, the Cache control logic judges whether the word is currently in the Cache according to the address: if it is, the cache hits; if not, the cache is missing (miss), and the word is read from the main memory to the CPU with the main memory read cycle, and At the same time, the entire data block containing this word is read from the main memory and sent to the cache.
3. Briefly describe the composition and working principle of the microcontroller.
Answer: The core component in the composition of the microprogram controller is the control memory (CM), which is implemented by the ROM device and is used to store the microprograms that implement the entire instruction system. (2 points)
The working principle of the microprogram controller: find the entry address of a microprogram corresponding to it according to the opcode of the read machine instruction, and read from the control memory one by one in the order determined by the specific function of the instruction. Read micro-instructions to "drive" each functional part of the computer to run correctly. (3 points)
2. Fill in the blanks
1. Microinstructions are composed of two parts : operation control and sequence control .
2. The time for the CPU to fetch an instruction from the main memory and execute the instruction is called the instruction cycle .
3. The representation methods of Chinese characters include: the input code of Chinese characters , the inner code of Chinese characters , and the sub-mode code of Chinese characters .
4. The DMA controller and the CPU use memory in time-sharing, usually in the following three ways: cycle embezzlement , alternate access to memory , and stop CPU access .
5. In the computer system, according to different application conditions and hardware resources, the following three methods can be used for information transmission: serial , parallel and time-sharing transmission .
6. The instruction format is a structural form in which the instruction word is expressed in binary code, and usually consists of an operation code and an address code .
7. In the hard-wired controller, the timing signal adopts a three-level system of main state cycle , beat point , and beat pulse .
8. According to different design methods, the operation controller can be divided intoThere are two kinds of sequential logic type and storage logic type . The first is called a hard-wired controller , which is implemented using sequential logic technology; the second is called a microprogram controller , which is implemented using storage logic.
9. Among the characteristics of the RISC instruction system, only the store/fetch instructions access the memory , and the operations of other instructions are performed between registers .
10. Dual-port memory and multi-module interleaved memory are parallel memory structures. The former uses space parallel technology, and the latter uses time parallel technology.
11. The technical indicators of memory include storage capacity, access time , storage cycle , and memory bandwidth .
12. The performance indicators of internal memory are mainly storage capacity and access speed , which can usually be described by access time , storage cycle and memory bandwidth .
13. The main technical indicators of disk storage include storage density , storage capacity , access time and data transfer rate.
14. According to the location of the bus arbitration circuit, the arbitration methods are divided into two types: centralized arbitration and distributed arbitration .
15. There are three centralized arbitration methods: chain query , counter timing query , and independent request . Among them, the independent request method has the fastest response time, and the daisy chain method is the most sensitive to circuit failure.
16. The reason why synchronous communication has a higher transmission frequency than asynchronous communication is because synchronous communication uses a common clock signal for synchronization .
17. The register that saves the address of the instruction currently being executed is AR .
18. The results of arithmetic and logic operations are usually placed in general-purpose registers and DR .
19. In the micro-program controller, the timing signal is relatively simple, and the two-level system of beat potential and beat pulse is generally used .
3. Calculation questions
1. Addition and subtraction of floating point numbers
2. Calculation related to hit rate
3. Correlation calculation of the three mapping methods
4.
Summarize
The above are some of the key points drawn by the teacher before the final exam. Although it is not very comprehensive, at least there is a direction and scope for the review. I hope it will be helpful to everyone!