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This article introduces the relevant knowledge of "what is the web interrupt mechanism". In the operation of actual cases, many people will encounter such a dilemma. Next, let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Concept

The operating system needs to manage peripherals, but the speed of peripherals is much lower than that of CPU, so we need a mechanism to bridge this speed gap and improve the efficiency of CPU.

For this reason, we introduce an interrupt mechanism to enable the peripheral to actively notify the operating system when it needs the operating system to deal with events related to the peripheral, that is, to interrupt the normal execution of the operating system and the application, so that the operating system can complete the relevant processing of the peripheral, and then resume the normal execution of the operating system and application.

When CPU receives an interrupted or abnormal event, it will suspend the execution of the current program or task, jump to the relevant routine responsible for handling the signal through a certain mechanism, and then jump back to the program or task that has just been interrupted after completing the processing of the event.

Classify asynchronous interrupts (asynchronous interrupt). External events caused by CPU external devices, such as Icano interrupts, clock interrupts, console interrupts, etc., are generated asynchronously (that is, the generated time is uncertain) and have nothing to do with the execution of CPU. Also known as external interrupt, referred to as interrupt (interrupt). Synchronous interrupt (synchronous interrupt) is an internal event caused by abnormal or illegal conditions detected during the execution of CPU instructions (such as zero error removal, address access out of bounds), also known as internal interrupt, or exception for short. An event raised by a system call that requests system services in a program, also known as a soft interrupt (soft interrupt), is caught in an trap interrupt.

Interrupt exception system call Source Peripheral Application Application response Asynchronous synchronous Asynchronous or synchronous processing Mechanism continues to be transparent to the user application to kill or re-execute unexpected application instructions to wait and persist

Interrupt descriptor table

Also known as interrupt descriptor table (Interrupt Descriptor Table).

In the operating system, some interrupt handling functions will be set in advance. When CPU receives the interrupt, it will find the corresponding processing function according to the interrupt number. The interrupt vector table is the table that records the mapping relationship between the interrupt number and the processing function.

The interrupt handling mechanism is as follows:

Interrupts, exceptions, and system calls are coordinated by the interrupt vector table.

When an interrupt occurs, the interrupt vector table is queried according to the interrupt vector number, and the device driver is coordinated to process the interrupt request of the external device according to the processing program inside. When the system call request occurs, the interrupt vector table queries the system call table. Then when the corresponding system call program is abnormal, query the interrupt vector table to get the corresponding exception handler. That's all for handling the exception "what is the web interrupt mechanism?" Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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