IBM nec pd78p081(a2) User Manual

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× ×

 IF=1?

× × 

MK=0?

× ×

 PR=0?

Any

Simultaneously

generated 

××

PR=0 interrupt

requests? 

Any

Simultaneously

generated high-priority

interrupt requests? 

IE=1?

ISP=1?

Vectored interrupt
servicing

Interrupt request
reserve 

Interrupt request
reserve 

Interrupt request
reserve 

Interrupt request
reserve 

Interrupt request
reserve 

Interrupt request
reserve 

Interrupt request
reserve 

Vectored interrupt
servicing

IE=1?

Yes (High priority)

Yes

No

Yes

No

No

No

Yes (Interrupt Request
        Generation)

No

Yes

No (Low Priority)

Yes

Yes

No

Yes

Yes

No

No

 Do any

of the simultaneously

generated 

××

PR=0 interrupt 

requests have a high

priority?

××

IF

: Interrupt request flag

××

MK : Interrupt mask flag

××

PR : Priority specify flag

IE

: Flag which controls maskable interrupt request acknowledgment (1 = enable, 0 = disable)

ISP

: Flag which indicates the priority of the interrupt currently being processed. (0 = high priority

interrupt being processed, 1= interrupt request not acknowledged, or low priority interrupt

being processed.)