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Interrupt handlers are initiated by hardware interrupts, software interrupt instructions, or software exceptions, and are used for implementing device drivers or transitions between protected modes of operation, such as system calls. The traditional form of interrupt handler is the hardware interrupt handler.
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 ...
IRQ 9 – Advanced Configuration and Power Interface (ACPI) system control interrupt on Intel chipsets. [6] And/or left for the use of peripherals (use depends on OS) IRQ 10 – The interrupt is left for the use of peripherals (for example, SCSI or NIC) IRQ 11 – The interrupt is left for the use of peripherals (for example, SCSI or NIC)
The interrupt controller sends an interrupt request (or IRQ) to the CPU with a certain priority level, and the CPU sets a mask that causes any other interrupts with a lower priority to be put into a pending state, until the CPU releases control back to the interrupt controller. If a signal comes in at a higher priority, then the current ...
On Intel systems, the LAPIC must be enabled for the PCI (and PCI Express) MSI/MSI-X to work, even on uniprocessor (single core) systems. [ 11 ] [ 12 ] In these systems, MSIs are handled by writing the interrupt vector directly into the LAPIC of the processor/core that needs to service the interrupt.
For example, hardware timers send interrupts to the CPU at regular intervals. Most operating systems execute a HLT instruction when there is no immediate work to be done, putting the processor into an idle state. In Windows NT, for example, this instruction is run in the "System Idle Process". On x86 processors, the opcode of HLT is 0xF4.
BIOS interrupt calls perform hardware control or I/O functions requested by a program, return system information to the program, or do both. A key element of the purpose of BIOS calls is abstraction - the BIOS calls perform generally defined functions, and the specific details of how those functions are executed on the particular hardware of the system are encapsulated in the BIOS and hidden ...
(Before Windows 8 claimed exclusive rights to this timer, it was also used by some programs like CPU-Z.) Under Microsoft Windows the APIC timer is not a shareable resource. [11] The aperiodic interrupts offered by the APIC timer are used by the Linux kernel tickless kernel feature. This optional but default feature is new with 2.6.18. When ...