EXCEPTION PROCESSING STATE (INTERRUPT PROCESSING)

INTERRUPT SYNCHRONIZED AND RECOGNIZED AS PENDING

ADDITIONAL INTERRUPTS DISABLED DURING FAST INTERRUPT

INTERRUPTS

RE-ENABLED

ADDITIONAL INTERRUPTS DISABLED DURING FAST INTERRUPT

INTERRUPTS

RE-ENABLED

MAIN

PROGRAM

MEMORY

n1

n2

n3

n4

n5

n6

n7

n8

n9

FOUR INSTRUCTION DECODES

ii1

ii2

ii1

ii2

ii= INTERRUPT INSTRUCTION n = NORMAL INSTRUCTION

(a)Instruction Fetches from Memory

INTERRUPT SYNCHRONIZED AND

RECOGNIZED AS PENDING

6 Icyc

INTERRUPTS RE-ENABLED

INTERRUPT CONTROL CYCLE 1

i

 

 

 

 

 

i

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INTERRUPT CONTROL CYCLE 2

 

i

 

 

 

 

 

i

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FETCH

n1

n2

ii1

ii2

n3

n4

n5

n6

ii1

ii2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DECODE

 

n1

n2

ii1

ii2

n3

n4

n5

n6

ii1

ii2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXECUTE

 

 

n1

n2

ii1

ii2

n3

n4

n5

n6

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

(b)Program Controller Pipeline

Figure 7-9 Two Consecutive Fast Interrupts

7 - 28

PROCESSING STATES

MOTOROLA

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Image 155
Motorola 24-Bit Digital Signal Processor, DSP56000 manual Two Consecutive Fast Interrupts