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I believe a nested interrupt, is where an interrupt is allowed to occur (and thus is handled) during an already occurring Interupt service ruotine.
I.E.
First interrupt occurs
ISR1 begins
second Interrupt occurs
ISR2 begins
ISR2 Finishes
ISR1 continues from where left off
ISR1 finishes
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∙ 12y ago
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Should any device be allowed to interrupt CPU while another interrupts are being serviced?
It is possible to allow nested interrupts. This is often done when there is a heirarchy of interrupts, some with higher priority than others. In order for this to work, the second interrupt must not be allowed to influence the progress of the first interrupt. We call this being "thread safe". In a nested scheme, an interrupt mask is set so that higher priority interrupts can be permitted, while blocking interrupts of the same or lower priority, and then interrupts are reenabled during the interrupt service routine. At the conclusion of the first routine, interrupts are disabled again, the mask is restored, and the normal interrupt return sequence is executed. In the 8085, this can be supported using the Read Interrupt Mask (RIM) and Set Interrupt Mask (SIM) instructions. While not strictly required, the logical priority is often INTR, RST5.5, RST6.6, RST7.5, and then TRAP, in order of increasing priority.
Why there is a need for disabling interrupts in 8085?
Interrupt are automatically disabled on interrupt entry (except for TRAP, which is non-maskable) so that interrupts do not, by default, nest. You would also disable enterrupts surrounding a critical section of code that, perhaps, manipulated an interrupt register. It is possible to re-enable interrupts during an interrupt service routine. Typically, you would have a hierarchy, such as RST7.5, then RST 6.5, then RST 5.5. Initially, at interrupt entry, all interrupts are disabled. You could then manipulate the interrupt mask using the RIM and SIM instructions and enable further interrupts, allowing a nested architecture. At interrupt exit, then, you would disable interrupts, reset the mask, enable interrupts, and return from interrupt.
What is nested logic?
In Nested Logic a Logic is contained within a Logic. If the Outer Logic is TRUE then the internal Logic is executed. Nested IF, Nested For, Nested While, e.t.c are some examples of Nested Logic in Modern Computer Languages.
When was Nested created?
Nested was created in 1977.
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"Have nested" is in the present perfect tense.
What is the if statement that appears inside another if statement?
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"Interrupt" is a verb.
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No, the CSS specifications explicitly state that CSS comments cannot be nested. If you try to do this, then your nested comments closing delimiter */ will close out the larger comment and anything after it will be rendered by the web browser. When comments are nested, the nested comment's beginning delimiter /* is ignored yet the closing */ is not.
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A nested watershed is simply a watershed within a watershed. An example might be the Platte River watershed which is a nested watershed within the Missouri River watershed which in turn is nested within the Mississippi River watershed.
What is the use of interrupt vector?
An interrupt vector is the memory address of an interrupt handler, or an index into an array called an interrupt vector table or dispatch table. Interrupt vector tables contain the memory addresses of interrupt handlers. When an interrupt is generated, the processor saves its execution state via a context switch, and begins execution of the interrupt handler at the interrupt vector.
What is nested tables in oracle9i?
multi-column nested table where customers can have multiple addresses
