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After completing the interrupt procedure, the processor:
1.
Copies the arithmetic controls field and the process controls field from the interrupt record
into the AC and PC, respectively. It then switches to the executing state and restores the
trace-enable bit to its value before the interrupt occurred.
2.
Deallocates the current stack frame and interrupt record from the interrupt stack and
switches to the stack it was using before servicing the interrupt.
3.
Performs a return operation as described in
4.
Resumes work on the program, if there are no pending interrupts to be serviced or trace
faults to be handled.
11.8.3.2
Servicing an Interrupt from Interrupted State
If the processor receives an interrupt while it is servicing another interrupt, and the new interrupt
has a higher priority than the interrupt currently being serviced, the current interrupt-handler
routine is interrupted. Here, the processor performs the same interrupt-servicing action as is
described in
Section 11.8.3.1
interrupt record is saved on the top of the interrupt stack prior to the new frame that is created for
use in servicing the new interrupt. See
On the return from the current interrupt handler to the previous interrupt handler, the processor
de-allocates the current stack frame and interrupt record, and stays on the interrupt stack.
11.9
OPTIMIZING INTERRUPT PERFORMANCE
Figure 11-13
depicts the path from interrupt source to interrupt service routine. This section
discusses interrupt performance in general and suggests techniques the application can use to get
the best interrupt performance.
CHAPTER 7, PROCEDURE
to save the state of the interrupted interrupt-handler routine. The
Figure
11-3.
INTERRUPTS
CALLS.
11
11-33
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