Freescale Semiconductor SC140 specifications Loop Nesting Rules, Rule SR.7, Rule L.N.1

Models: SC140

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Static Programming Rules

Rule SR.7

The following instructions that affect status bits in SR cannot be grouped in a VLES with a MOVE-like instruction that reads the SR register:

BREAK

CONT/CONTD

DI and EI

DOENn and DOENSHn

SKIPLS

For mutually exclusive IFc subgroups in a VLES, this rule applies independently to each subgroup.

Example 7-47. Status Bit Update with SR Read

doen0 #5

move.l sr,d0

;not allowed

di

push sr

;not allowed

skipls _dest

bmtsts #4,sr.h

;not allowed

7.5.7 Loop Nesting Rules

Rule L.N.1

Nested loops cannot have the same LA.

Example 7-48. Nested Loops with the Same LA

...

;LA

move.w r3,(r4)

loopend1

;not allowed

loopend0

7-28

SC140 DSP Core Reference Manual

Page 278
Image 278
Freescale Semiconductor SC140 specifications Loop Nesting Rules, Rule SR.7, Rule L.N.1, DI and EI DOENn and DOENSHn