![](/images/backgrounds/204754/bga1.png)
n2
i1
MAIN
PROGRAM
FETCHES
n1 REP m
n2
INTERRUPT SYNCHRO-
NIZED AND RECOGNIZED
AS PENDING
ADDITIONAL INTERRUPTS
DISABLED DURING
FAST INTERRUPT
FAST INTERRUPT
SERVICE ROUTINE FETCHES
(FROM BETWEEN P:$0000
AND P:$003F)
i2
n2
n3
n4
n5
n6
INTERRUPTS
RE-ENABLED
n2 n2
INSTRUCTION n2
REPLACED PER
THE REP INSTRUCTION
i = INTERRUPT INSTRUCTION
n = NORMAL INSTRUCTION
Figure 7-13 Interrupting an REP Instruction(a) Instruction Fetches from Memory
INTERRUPT CONTROL CYCLE 1 ii
INTERRUPT CONTROL CYCLE 2 i% i
FETCH REP n2 n3 n4 ii1 ii2 n5 n6
DECODE REP NOP n2 n2 n2 n2 n3 n4 ii1 ii2 n5
EXECUTE REP NOP n2 n2 n2 n2 n3 n4 ii1 ii2
INSTRUCTION CYCLE COUNT 1 2 3 4 5 6 7 8 9 10 11 12
i = INTERRUPT
ii = INTERRUPT INSTRUCTION WORD
n = NORMAL INSTRUCTION WORD
i% = INTERRUPT REJECTED
INTERRUPT SYNCHRONIZED AND
RECOGNIZED AS PENDING
INTERRUPTS RE-ENABLED
(b) Program Controller Pipeline
REPEAT
m TIMES