7 loop nesting rules, Loop nesting rules -28, Status bit update with sr read -28 – Freescale Semiconductor StarCore SC140 User Manual
Page 278: Nested loops with the same la -28
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SC140 DSP Core Reference Manual
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
...
move.w r3,(r4)
;LA
loopend1
loopend0
;not allowed