Search results
Results from the WOW.Com Content Network
In computing, a non-maskable interrupt (NMI) is a hardware interrupt that standard interrupt-masking techniques in the system cannot ignore. It typically occurs to signal attention for non-recoverable hardware errors. Some NMIs may be masked, but only by using proprietary methods specific to the particular NMI.
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 ...
During normal operation the computer regularly kicks Stage1 to prevent a timeout. If the computer fails to kick Stage1 (e.g., due to a hardware fault or programming error), Stage1 will eventually timeout. This event will start the Stage2 timer and, simultaneously, notify the computer (by means of a non-maskable interrupt) that a reset is imminent.
The detection of an NMI or IRQ signal, as well as the execution of a BRK instruction, will cause the same overall sequence of events, which are, in order: [1] [3]. The processor completes the current instruction and updates registers or memory as required before responding to the interrupt.
The system used by NAPI is an example of the hardware-based approach: the system (driver) starts in interrupt enabled state, and the Interrupt handler then disables the interrupt and lets a thread/task handle the event(s) and then task polls the device, processing some number of events and enabling the interrupt.
If an interrupt descriptor table specifies an IST entry to use (there are 7), the processor will load the new stack from the IST instead. This allows known-good stacks to be used in case of serious errors (NMI or Double fault for example). Previously, the entry for the exception or interrupt in the IDT pointed to a task gate, causing the ...
An interrupt control register, or ICR, is a hardware register in a computer chip used to configure the chip to generate interrupts—to raise a signal on an interrupt line—in response to some event occurring within the chip or a circuit connected to the chip. [1] [2]
A non-maskable interrupt (NMI), which can be used to respond to power-down situations or other high-priority events (and allowing a minimalistic Z80 system to easily implement a two-level interrupt scheme in mode 1).