Freescale Semiconductor StarCore SC140 - Manual (Page 283)

Static Programming Rules
SC140 DSP Core Reference Manual 7-33
Rule L.L.5
A MOVE-like instruction that writes the SR register is not allowed at LA-4, LA-3, LA-2, LA-1, or LA of a
long loop.
Rule L.L.6
A MOVE-like instruction that writes the SR register is not allowed at SA-2 or SA-1 of a short loop.
7.5.9 Loop Sequencing Rules
Rule L.D.1
At least one VLES is required between the following instructions that write any LCn register and the
SKIPLS instruction:
• Any DOENn Dn (data register)
• Any DOENSHn Dn (data register)
• MOVE-like instruction that writes any LCn register
Example 7-58. LCn Write to SKIPLS Instruction
doen0 d2
skipls label4
; not allowed
Rule L.D.2
The minimum number of VLES between the following instructions that write a LCn register and LA of the
same long loop n is:
• DOENn Rn or #x: three VLES (address register or immediate value)
• DOENn Dn: four VLES (data register)
• MOVE-like instruction that writes a LCn register: four VLES
Example 7-59. LCn Write at the End of Long Loop n
move.w #3,d8
dosetup1 label1
doen1 d8
;not allowed
nop
loopstart1
label1 inc d3
inc d4
inc d5
loopend1