EXCEPTION PROCESSING STATE (INTERRUPT PROCESSING)

MAIN

PROGRAM

n1

n2

FAST INTERRUPT

VECTOR

JSR

NOT USED

LONG INTERRUPT

SUBROUTINE

ii2

ii3

ii4

iin

RTI

(a) Instruction Fetches from Memory

INTERRUPT SYNCHRONIZED AND

RECOGNIZED AS PENDING

INTERRUPTS RE-ENABLED

INTERRUPT CONTROL CYCLE 1

i

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INTERRUPT CONTROL CYCLE 2

 

i

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FETCH

 

n1

JSR

ii2

ii3

ii4

iin

RTI

n2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DECODE

 

 

n1

JSR

NOP

ii2

ii3

ii4

iin

RTI

NOP

n2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXECUTE

 

 

 

n1

JSR

NOP

ii2

ii3

ii4

iin

RTI

NOP

n2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INSTRUCTION CYCLE COUNT

1

2

3

4

5

6

7

8

9

10

11

12

13

 

 

 

 

 

 

 

 

 

 

 

 

 

 

i= INTERRUPT

ii= INTERRUPT INSTRUCTION WORD n = NORMAL INSTRUCTION WORD

(b)Program Controller Pipeline

Figure 7-11 JSR First Instruction of a Fast Interrupt

MOTOROLA

PROCESSING STATES

7 - 31

Page 158
Image 158
Motorola DSP56000, 24-Bit Digital Signal Processor manual JSR First Instruction of a Fast Interrupt