What hardware can the CPU directly access?

The hardware that the cpu can directly access is the internal memory; the internal memory is directly connected to the cpu and is one of the important components in the computer. The internal memory is the bridge between the computer and the cpu. The storage capacity is small, but It is fast and is used to store the instructions and data of the currently running program and exchange information directly with the CPU.

The operating environment of this tutorial: Windows 10 system, DELL G3 computer.

What is the hardware that the CPU can directly access?

The memory that the CPU can directly access is the internal memory

The internal memory is one of the important components in the computer First, it is a bridge to communicate with the CPU. All programs in the computer are run in the internal memory, so the performance of the internal memory has a great impact on the computer.

The internal memory is directly connected to the CPU. It has a small storage capacity but is fast. It is used to store the instructions and data of the currently running program and exchange information directly with the CPU. The internal memory is composed of many storage units, each unit can store a binary number or an instruction represented by a binary code. Internal memory is composed of random access memory and read-only memory.

Internal memory structure

The central processing unit CPU can only directly access the data stored in the memory, while the data in the external memory can only be transferred into the memory first Only then can it be accessed and processed by the central processor.

When the content in the internal memory is to be read and written, the memory address from the address bus is decoded by the address decoder, and the designated storage unit is selected, and the read and write control circuit is based on the read and write Commands implement access operations to the memory, and the data bus is used to transmit information written to or read from the internal memory.

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Memory directly accessed by the CPU: cache (cache), read-only memory (ROM), Random access memory (RAM).

The cache usually includes first-level, second-level and third-level caches, which are directly integrated inside the CPU. They have small capacity but very fast speed to meet the CPU's access to commonly used data; ROM is generally used in SOCs. In a CPU system, ordinary PCs only have BIOS information stored in ROM; RAM is commonly referred to as memory. Because the CPU integrates a memory controller, it can be accessed directly. The speed is slower than the cache but the capacity is much larger.

1. Processing instructions

English Processing instructions; this refers to the execution sequence of instructions in the control program. There is a strict sequence between the instructions in the program, and they must be executed strictly in the order specified by the program to ensure the correctness of the computer system.

2. Perform an action

English Perform an action; the function of an instruction is often implemented by components in the computer executing a sequence of operations. The CPU should generate corresponding operation control signals according to the function of the instruction and send them to the corresponding components, thereby controlling these components to act according to the requirements of the instruction.

3. Control time

English Control time; time control is to implement time timing for various operations. During the execution of an instruction, what operations are performed at what time should be strictly controlled. Only in this way can the computer work in an orderly manner.

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