Freescale Semiconductor StarCore SC140 - Manual (Page 535)

LPMARKx
SC140 DSP Core Reference Manual A-221
L-M
LPMARKx
End-of-Loop Mark (PREFIX)
LPMARKx
Description
The LPMARK prefix bits are used for hardware loops and perform the operations associated with ending a
loop iteration: a conditional jump to the start of the loop (based on the value of LCn) and a decrement of
LCn. In the case where LCn indicates the last iteration, these bits disable the active loop and do not jump.
The LPMARK bits use the SAn/LCn register of the active loop as specified by the LF bits in SR.
The LPMARK bits are encoded in the prefix words, and are not independent instructions. They are
generated automatically by the assembler at the correct positions based on the LOOPSTART and
LOOPEND assembly directives inserted by the programmer. The assembler does not allow the
programmer to use LPMARKx.
Operation Disassembler Syntax Only
If LCn > 1, then SAn
→ PC
LCn – 1
→ LCn
else next PC
→ PC
0
→ LCn
0
→ LFn
LPMARKB (long loop)
If LCn > 1, then SAn
→ PC
LCn – 1
→ LCn
else next PC
→ PC
0
→ LCn
0
→ LFn
LPMARKA (external of nested loops)
If LCn > 1, then SAn
→ PC
LCn – 1
→ LCn
else next PC
→ PC
0
→ LCn
0
→ LFn
0
→ SLF
LPMARKB (short loop of 2 sets)
If LCn > 1, then SAn
→ PC
LCn – 1
→ LCn
else next PC
→ PC
0
→ LCn
0
→ LFn
0
→ SLF
LPMARKA (short loop of 1 set)