Interrupting Sequential Rep Instructions - Motorola DSP56000 Manual

INTERRUPT
REJECTED
INTERRUPT
PENDING
INTERRUPT
INTERRUPT REJECTED
PENDING
INTERRUPT
REJECTED
INTERRUPT
PENDING
INTERRUPT
PENDING
INTERRUPT CONTROL CYCLE 1
INTERRUPT CONTROL CYCLE 2
FETCH REP n2
DECODE
EXECUTE
INSTRUCTION CYCLE COUNT
i = INTERRUPT
ii = INTERRUPT INSTRUCTION WORD
n = NORMAL INSTRUCTION WORD
i% = INTERRUPT REJECTED
Figure 7-14 Interrupting Sequential REP Instructions
MOTOROLA
RESET PROCESSING STATE
MAIN
PROGRAM
FETCHES
REP m n1
n2
REP m n3
n4
REP m n5
n6
n7
n8
n9
(a) Instruction Fetches from Memory
INTERRUPT SYNCHRONIZED AND
RECOGNIZED AS PENDING
i
i%
REP n4
REP NOP n2 n2 n2 REP NOP
REP NOP n2 n2 n2
1 2 3 4 5 6 7
(b) Program Controller Pipeline
PROCESSING STATES
REPEAT m
TIMES
• •
n2
n2
ii1
ii2
REP n6 n7
n4 n4 n4 REP NOP n6
REP NOP n4 n4 n4 REP NOP n6
8 9 10 11 12 13
n2
•
REPEAT m
TIMES
n4
• • •
n4
n4
REPEAT m TIMES
n6
• • •
n6
n6
INTERRUPTS RE-ENABLED
i
i
n8 ii1 ii2 n9
n6 n6 n7 n8 ii1 ii2
n6 n6 n7 n8 ii1
14 15 16 17 18 19 20
7 - 35
n9
ii2 n9
21 22