Freescale Semiconductor StarCore SC140 - Manual (Page 284)

7-34 SC140 DSP Core Reference Manual
Static Programming Rules
Rule L.D.3
The minimum number of VLES between the following instructions that write a LCn register and SA of the
same short loop n is:
• DOENSHn Rn or #x: one VLES (address register or immediate value)
• DOENSHn Dn: two VLES (data register)
• MOVE-like instruction that writes a LCn register: two VLES
Example 7-60. LCn Write at the Start of Short Loop n
move.w #3,r0
doensh0 r0
;allowed
move.l d1,lc0 ;not allowed
move.w #2,d2
loopstart0
inc d1
loopend0
Rule L.D.5
The minimum number of VLES between an instruction that writes any LCn register and a CONT/CONTD
instruction is:
• Any DOENn Rn or #x : one VLES (address register or immediate value)
• Any DOENn Dn: two VLES (data register)
• MOVE-like instruction that writes any LCn register: two VLES
Example 7-61. LCn Write to CONT/D Instruction
doen1 #5
...
loopstart1
loop1 nop
move.l d0,lc1
nop
cont label
;not allowed
nop
nop
loopend1
Rule L.D.6
A MOVE-like instruction that writes a SAn register is not allowed at (LA-3), (LA-2), (LA-1), and LA of
the same long loop n.