(b) Program Controller Pipeline Figure 7-7 Trace Exception

EXCEPTION PROCESSING STATE (INTERRUPT PROCESSING)

MAIN

PROGRAM FETCHES

TRACE INSTRUCTION n1

TRACE BIT SET IN SR

n1

n2

NEXT TRACE OPERATION

NOP

NOP

NOP

JSR

NOT USED

DEBUGGER PROGRAM

RTI

THREE NOP INSTRUCTIONS INSERTED BY TRACE MODE

FAST INTERRUPT

CAUSED BY TRACE

INTERRUPT

SET TRACE BIT IN SSL

(a) Instruction Fetches from Memory

INTERRUPT SYNCHRONIZED AND

RECOGNIZED AS PENDING

INTERRUPT SYNCHRONIZED AND

RECOGNIZED AS PENDING

INTERRUPT CONTROL CYCLE 1

i

 

 

 

 

 

 

 

 

 

 

 

i

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INTERRUPT CONTROL CYCLE 2

 

i

 

 

 

 

 

 

 

 

 

 

 

 

i

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FETCH

 

n1

NOP

NOP

NOP

JSR

TRACE PROGRAM

RTI

n2

NOP

NOP

NOP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DECODE

 

 

n1

NOP

NOP

NOP

JSR

NOP

TRACE PROGRAM

RTI

NOP

n2

NOP

NOP

NOP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXECUTE

 

 

 

n1

NOP

NOP

NOP

JSR

NOP

TRACE PROGRAM

RTI

NOP

n2

NOP

NOP

NOP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INSTRUCTION CYCLE COUNT

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

i= INTERRUPT

ii= INTERRUPT INSTRUCTION WORD II = ILLEGAL INSTRUCTION

n = NORMAL INSTRUCTION WORD

MOTOROLA

PROCESSING STATES

7 - 23

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Motorola DSP56000, 24-Bit Digital Signal Processor manual Main Program Fetches