Digital Photo Keychain User Manual

EXCEPTION PROCESSING STATE (INTERRUPT PROCESSING)
7 - 20 PROCESSING STATES MOTOROLA
I1
I2
MAIN
PROGRAM
FETCHES
II (NOP)
n6
NO FETCH
NO FETCH
LONG INTERRUPT
SERVICE ROUTINE
FETCHES
Figure 7-5 Illegal Instruction Interrupt Serviced by a Long Interrupt
INTERRUPT CONTROL CYCLE 1
i
INTERRUPT CONTROL CYCLE 2
i
FETCH
n1 n2 n3 n4 n5 n6 — — ii1 ii2 ii3 ii4 ii5
DECODE
n1 n2 n3 n4 II — — — ii1 ii2 ii3 ii4
EXECUTE
n1 n2 n3 n4 NOP — — — ii1 ii2 ii3
INSTRUCTION CYCLE COUNT
1 2 3 4 5 6 7 8 9 10111213 14
i = INTERRUPT
ii = INTERRUPT INSTRUCTION WORD
II = ILLEGAL INSTRUCTION
n = NORMAL INSTRUCTION WORD
ILLEGAL INSTRUCTION INTERRUPT
RECOGNIZED AS PENDING
ILLEGAL INSTRUCTION INTERRUPT
RECOGNIZED AS PENDING
(a) Instruction Fetches from Memory
(b) Program Controller Pipeline
I3
I4
I5