Exception Processing

The following pipeline table shows the first case in Example 5-17. ES0 is a JMP with a minimum cycle count of three. ES1 and ES2 are not change-of-flow instructions. And, I1 is the first instruction at the exception vector address. The exception request is initiated in cycle 4.

Table 5-21. Pipeline Example

 

 

 

 

 

 

Instruction Cycle

 

 

 

 

 

Operation

 

 

 

 

 

 

 

 

 

 

 

 

 

1

2

3

4

5

 

6

7

8

9

10

11

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pre-fetch

ES0

 

 

ES1

ES2

 

 

I1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fetch

 

ES0

 

 

ES1

 

ES2

 

I1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Decode

 

 

ES0

 

 

 

ES1

ES2

push

I1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Address

 

 

 

ES0

 

 

 

ES1

ES2

push

I1

 

 

Generation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Execute

 

 

 

 

ES0

 

 

 

ES1

ES2

push

I1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5-56

SC140 DSP Core Reference Manual

Page 236
Image 236
Freescale Semiconductor SC140 specifications Pipeline Example, Instruction Cycle Operation