NEC mPD780065 Series Preliminary User's Manual page 281

Example 3. Multiple interrupt servicing does not occur because interrupt is not enabled
Interrupt is not enabled during servicing of interrupt INTxx (EI instruction is not issued), therefore, interrupt request
INTyy is not acknowledged and multiple interrupt servicing does not take place. The INTyy interrupt request is held
pending, and is acknowledged following execution of one main processing instruction.
PR = 0: Higher priority level
IE = 0: Interrupt request acknowledge disabled
CHAPTER 17 INTERRUPT FUNCTIONS
Figure 17-13. Multiple Interrupt Examples (2/2)
Main processing
IE = 0
EI
INTyy
(PR = 0)
INTxx
(PR = 0)
1 instruction execution
Preliminary User's Manual U13420EJ2V0UM00
INTxx servicing INTyy servicing
RETI
IE = 0
RETI
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