Interrupting the whole process refers to the start of an interrupt request from the interrupt source, CPU in response to this request, the current program is interrupted, go to the interrupt service routine, until the interrupt service routine is finished, CPU and then return the entire process of the original program to continue.
Interrupting the whole process can be substantially divided into five phases: an interrupt request, interrupt arbitration, interrupt, and interrupt return interrupt processing.
Interrupt processing consists of three parts consisting essentially of:
The first part is ready to part, the basic function is to protect the site for non-vectored interrupt you need to determine the interrupt source, interrupt finally open, allowing more advanced low-level interrupt requests to interrupt the interrupt service routine;
The second part is the processing part, that is really the interrupt service routine for a specific interrupt source services;
The third part is the end portion, the first to break off, in order to prevent the new interrupt request is interrupted during the restoration site, followed by the recovery site, and then open the interrupt, to return in response to other interrupt request after the original program. The last instruction of the interrupt service routine must interrupt return instruction.
