The main components of the CPU are the controller and the arithmetic unit. The arithmetic unit refers to the component in the computer that performs various arithmetic and logical operations. The arithmetic logic unit is part of the central processing core. The basic operations of the arithmetic unit include the four arithmetic operations of addition, subtraction, multiplication, and division, and, or, not, Logical operations such as XOR, and operations such as shifts, comparisons, and transfers. The controller is composed of program status register PSR, system status register SSR, program counter PC, instruction register, etc. Its main task is to issue commands and play a coordination and command role in the operation of the entire computer system.
The operating environment of this article: Windows 7 system, Dell G3 computer.
The main components of the CPU are the controller and the arithmetic unit.
CPU mainly includes two parts, namely the controller and the arithmetic unit, which also include cache memory and the data and control bus that realize the connection between them.
Operator
The basic operations of the operator include the four arithmetic operations of addition, subtraction, multiplication, and division, and, or, and not , logical operations such as XOR, and operations such as shifts, comparisons, and transfers, also known as arithmetic logic units (ALU).
The arithmetic unit refers to the component in the computer that performs various arithmetic and logical operations. The arithmetic logic unit is part of the central processing core.
(1) Arithmetic logic unit (ALU). Arithmetic logic unit refers to a combinational logic circuit that can realize multiple sets of arithmetic operations and logical operations. It is an important part of central processing. The operations of the arithmetic logic unit are mainly two-bit arithmetic operations, such as addition, subtraction, and multiplication. During the operation process, the arithmetic logic unit mainly performs arithmetic and logical operations using computer instructions. Generally speaking, the ALU can play the role of direct read-in and read-out, which is specifically reflected in the processor controller, memory and input and output devices. , input and output are implemented based on the bus. The input command contains an instruction word, including operation code, format code, etc.
(2) Intermediate register (IR). Its length is 128 bits, and its actual length is determined by the operands. IR plays an important role in the "push and fetch" instruction. During the execution of this instruction, the content of ACC is sent to IR, then the operand is fetched to ACC, and then the content of IR is pushed onto the stack.
(3) Operation accumulator (ACC). Current registers are generally single accumulators with a length of 128 bits. For ACC, it can be regarded as a variable-length accumulator. In the process of describing instructions, the expression of ACC length is generally based on the value of ACS, and the ACS length is directly related to the ACC length. Doubling or halving the ACS length can also be regarded as doubling or halving the ACC length.
(4) Descriptor register (DR). It is mainly used to store and modify descriptors. The length of DR is 64 bits. In order to simplify data structure processing, the use of descriptors plays an important role.
(5)B register. It plays an important role in the modification of instructions. The length of the B register is 32 bits. It can save the address modification amount during the address modification process. The main memory address can only be modified with a descriptor. The descriptor points to the first element in the array, so accessing other elements in the array should require modifiers. For arrays, they are composed of data or elements of the same size and are stored continuously. The common access method is a vector descriptor, because the address in the vector descriptor is a byte address, so when proceeding During the conversion process, the base addresses should first be added. For the conversion work, it is mainly implemented automatically by the hardware. In this process, special attention must be paid to alignment to avoid exceeding the array boundaries.
Controller
The computer controller is the nerve center of the computer, directing all components in the machine to work in automated coordination. Under the control of the controller, the computer can automatically perform a series of operations according to the steps set by the program to complete specific tasks.
The controller is composed of program status register PSR, system status register SSR, program counter PC, instruction register, etc. As a "decision-making mechanism", its main task is to issue commands and play a role in the coordination and coordination of the entire computer system operation. command role.
The classification of control mainly includes two types, namely combinational logic controller and microprogrammed controller. Both parts have their own advantages and disadvantages. Among them, the combinational logic controller has a relatively complex structure, but its advantage is that it is faster; the microprogrammed controller has a simple structure, but when modifying a machine instruction function, the entire microprogram needs to be reprogrammed.
Related introduction:
Central processing unit (CPU) is one of the main devices of electronic computers and a core accessory in computers. Its function is mainly to interpret computer instructions and process data in computer software. The CPU is the core component of the computer that reads instructions, decodes them, and executes them. The central processing unit mainly consists of two parts, namely the controller and the arithmetic unit, which also include cache memory and the data and control bus that realize the connection between them. The three core components of an electronic computer are the CPU, internal memory, and input/output devices. The main functions of the central processing unit are to process instructions, perform operations, control time, and process data.
In computer architecture, the CPU is the core hardware unit that controls and allocates all hardware resources of the computer (such as memory, input and output units) and performs general operations. The CPU is the computing and control core of the computer. The operations of all software layers in the computer system will eventually be mapped to CPU operations through the instruction set.
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