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In computer systems programming, an interrupt handler, also known as an interrupt service routine or ISR, is a special block of code associated with a specific interrupt condition. Interrupt handlers are initiated by hardware interrupts, software interrupt instructions, or software exceptions , and are used for implementing device drivers or ...
This definition originates from multiprogramming environments, where multiple processes may be active concurrently and where the flow of control could be interrupted by an interrupt and transferred to an interrupt service routine (ISR) or "handler" subroutine. Any subroutine used by the handler that could potentially have been executing when ...
A hardware interrupt is a condition related to the state of the hardware that may be signaled by an external hardware device, e.g., an interrupt request (IRQ) line on a PC, or detected by devices embedded in processor logic (e.g., the CPU timer in IBM System/370), to communicate that the device needs attention from the operating system (OS) [7] or, if there is no OS, from the bare metal ...
When an I/O device interrupts a program, it places the address of its vector on the bus to indicate which service routine should take control. The lowest vectors are service routines to handle various types of trap. Traps occur on some program errors, such as an attempt to execute an undefined instruction; and also when the program executes an ...
Upon completion of the service routine, the RTI instruction would be used to return control to the program that made the operating system call. Note that the signature for BRK may be any value, whereas the signature for COP should be limited to the range $00-$7F. [2] The use of BRK and/or COP to request an operating system service means user ...
Interrupts cause the central processing unit (CPU) to have a control flow change away from the currently running program to an interrupt handler, also known as an interrupt service routine (ISR). [54] [55] An interrupt service routine may cause the central processing unit (CPU) to have a context switch. [56] [a] The details of how a computer ...
Diagram about the course of an interrupt routine. In a computer, an interrupt request (or IRQ) is a hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead.
Subprogram, routine and subroutine were more commonly used in the past but are less common today; Routine and subroutine have essentially the same meaning but describe a hierarchical relationship, much like how a subdirectory is structurally subordinate to its parent directory; program and subprogram are similarly related