Editing Interrupt (section)

===Software interrupts===
A software interrupt is requested by the processor itself upon executing particular instructions or when certain conditions are met. Every software interrupt signal is associated with a particular interrupt handler.

A software interrupt may be intentionally caused by executing a special [[instruction (computer science)|instruction]] which, by design, invokes an interrupt when executed.{{efn|See [[INT (x86 instruction)]]}} Such instructions function similarly to [[subroutine call]]s and are used for a variety of purposes, such as requesting operating system services and interacting with [[device driver]]s (e.g., to read or write storage media). Software interrupts may also be triggered by program execution errors or by the [[virtual memory]] system.

Typically, the operating system [[Kernel (operating system)|kernel]] will catch and handle such interrupts. Some interrupts are handled transparently to the program - for example, the normal resolution of a [[page fault]] is to make the required page accessible in physical memory. But in other cases such as a [[segmentation fault]] the operating system executes a process callback. On [[Unix-like]] [[operating system]]s this involves sending a [[Signal (IPC)|signal]] such as [[SIGSEGV]], [[SIGBUS]], [[SIGILL]] or [[SIGFPE]], which may either call a signal handler or execute a default action (terminating the program). On Windows the callback is made using [[Structured Exception Handling]] with an exception code such as STATUS_ACCESS_VIOLATION or STATUS_INTEGER_DIVIDE_BY_ZERO.<ref>{{cite web |title=Hardware exceptions |url=https://docs.microsoft.com/en-us/cpp/cpp/hardware-exceptions?view=msvc-170 |website=docs.microsoft.com |language=en-us |date=3 August 2021}}</ref>

In a kernel [[process (computing)|process]], it is often the case that some types of software interrupts are not supposed to happen. If they occur nonetheless, an [[Crash (computing)#Operating system crashes|operating system crash]] may result.