Freescale Semiconductor StarCore SC140 - Manual (Page 286)

7-36 SC140 DSP Core Reference Manual
Static Programming Rules
7.5.10 Loop COF Rules
Rule L.C.1
A COF instruction cannot have a COF destination that is LA-1 or LA of a long loop, or LA of a 2-VLES
short loop. This rule does not apply to loop COF instructions (BREAK, CONT, CONTD and SKIPLS) in a
nested loop having a COF destination that is LA-1 or LA of an enveloping loop.
Example 7-65. COF Destination to Loop Delay Slots
doensh1 #5
...
cmpeq.w #3,d0
jf _dest
;not allowed
inc d0
loopstart1
inc d0
_dest add d1,d2,d3
loopend1
Rule L.C.2
COF instructions, WAIT and STOP are not allowed at LA-2 of a long loop.
Example 7-66. COF Instructions at LA-2 of a Long Loop
dosetup1 label1
doen1 #n2
move.l #mem_l1,r1
move.l #mem_l2,r0
loopstart1
label1 inc d1
jsr r1 ;LA-2, not allowed
add d1,d2,d3 ;LA-1
move.w d3,(r0) ;LA
loopend1
bra label2
Rule L.C.3
A Bc or Jc instruction is not allowed at SA-1 of a short loop.
Example 7-67. Bc/Jc at SA-1 of a Short Loop
cmpgt d4,d3
nop
iff doensh3 #count2
bt _dest
;SA-1, not allowed
loopstart3
inc d2
loopend3
...
_dest inc d2