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System Reset and Initialization
Return From Interrupt
The interrupt handling routine terminates with the instruction:
The return from the interrupt takes 5 cycles to execute the following actions
and is illustrated in Figure 2−8.
1) The SR with all previous settings pops from the stack. All previous settings
2) The PC pops from the stack and begins execution at the point where it was
Figure 2−8. Return From Interrupt
SP
Interrupt Nesting
Interrupt nesting is enabled if the GIE bit is set inside an interrupt service
routine. When interrupt nesting is enabled, any interrupt occurring during an
interrupt service routine will interrupt the routine, regardless of the interrupt
priorities.
2-12
System Resets, Interrupts, and Operating Modes
(return from an interrupt service routine)
RETI
of GIE, CPUOFF, etc. are now in effect, regardless of the settings used
during the interrupt service routine.
interrupted.
Before
Return From Interrupt
Item1
SP
Item2
PC
TOS
SR
After
Item1
TOS
Item2
PC
SR
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