RTSTK

Example rtstk

Instruction

Comment

 

- - -

Jump to subroutine at SUB. Push the PC and SR onto the

 

jsr SUB

 

stack.

 

- - -

Skip over these instructions.

SUB

MOVE.w #$16,d4

Execute the subroutine here.

 

- - -

Change the original value in the stack for PC to lbl.

 

move.w #lbl,(SP-8)

 

rtstk

Restore the new value lbl to PC.

 

move.l #$16,d5

This instruction skipped.

lbl

move.l #$16,d6

Continue executing here.

Instruction Formats and Opcodes

Instruction

Words

Cycles1

Type

RTSTK

1

5/6

4

Opcode

15

8

7

0

1 0 0 1 1 1 1 1 0 1 1 1 0 1 0 1

Note 1: RTSTK uses 5 cycles if the shadow SP is valid. RTSTK uses 6 cycles if the shadow SP is not valid.

SC140 DSP Core Reference Manual

A-375

Page 689
Image 689
Freescale Semiconductor SC140 specifications Example rtstk, Instruction Comment