isr

When you disable interrupts (with the cli instruction in x86), what exactly happens? Does the PIC wait for you to turn on interrupts, and fire the interrupt when that happens? (If so, how long does it wait, and what happens if the time 'expires'?) Does the interrupt -- from the device's perspective -- get sent into a "black hole", with no response? Does the PIC somehow tell the device that "the CPU is busy" or something? Or does something else happen? Also, how do you deal with an interrupt you don't know how to handle? Is there some way to tell the PIC (or the device, if you don't know what

I want to understand difference between ISR (Interrupt Service Routine) and Function call. I feel both the function call and ISR are the same from the hardware perspective. Please Correct me if I am wrong. All I could found about ISR and Function call is as follows: ISR: Asynchronous event that can occur any time during the execution of the program Saves the PC, Flags and registers on the stack and disables all the interrupts and loads the address of the ISR ISR cannot have arguments that can be passed to it Cannot return values Enables the interrupts Generally small as they are taking the

Based on various references, my subjective definition of signals in Linux is "The triggers that are used to notify the processes about an occurrence of a specific event.Event here may refer to a software exception.Additionally signals may also be used for IPC mechanisms." The questions I have are I presume only exceptions (software interrupts) are notified via signals.What about the case of hardware interrupts. What are the various sources of the signal? To me it looks like kernel is always the source of a signal.(except when used for IPC) Difference between the signal handler and the ISR?.

I am looking at some old code from a school project, and in trying to compile it on my laptop I ran into some problems. It was originally written for an old 32 bit version of gcc. Anyway I was trying to convert some of the assembly over to 64 bit compatible code and hit a few snags. Here is the original code: pusha pushl %ds pushl %es pushl %fs pushl %gs pushl %ss pusha is not valid in 64 bit mode. So what would be the proper way to do this in x86_64 assembly while in 64 bit mode? There has got to be a reason why pusha is not valid in 64 bit mode, so I have a feeling manually pushing all the

I want to know the difference between FIQ and IRQ interrupt system in any microprocessor, e.g: ARM926EJ. A feature of modern ARM CPUs (and some others). From the patent: A method of performing a fast interrupt in a digital data processor having the capability of handling more than one interrupt is provided. When a fast interrupt request is received a flag is set and the program counter and condition code registers are stored on a stack. At the end of the interrupt servicing routine the return from interrupt instructions retrieves the condition code register which contains the status of the