Freescale Semiconductor SC140 Lpmark Rule L.L.2, Lpmark Rule L.L.3, Lpmark Rule L.L.5

Models: SC140

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LPMARK Rules

LPMARK Rule L.L.2

A DOENn or MOVE-like instruction that writes the active LCn register is not allowed at LPB, LPB+1, or LPB+2 of a long loop.

Example 7-93. Active LCn Write at the End of Long Loops

doen1 #3

move.l #$12345678,r1

inc d0

 

{lpmarkb set}

doen1 #5

;not allowed

move.w

d3,(r1)+

LPMARK Rule L.L.3

The following instructions are not allowed at LPA, LPB, or LPB+1 of a short loop:

COF instructions

STOP and WAIT

DI

DEBUG

DOENn/DOENSHn

MOVE-like instructions that read any LCn register

MOVE-like instructions that write any LCn register

MOVE-like instructions that read the SR register

MOVE-like instructions that write the SR register

This rule does not apply to other instructions that affect status bits in SR.

Example 7-94. Instructions in Short Loops

move.w #count2,r6 doensh0 r6 move.w #3,d3

inc d3

{lpmarkb set}

;not allowed

wait

 

doensh0 #$10

 

 

nop

 

 

jmp end

{lpmarka set}

;not allowed

doensh1 #count2

 

move.w #num,d2

 

doen1 #5

{lpmarka set}

;not allowed

LPMARK Rule L.L.5

AMOVE-like instruction that writes the SR register is not allowed at LPB-2, LPB-1, LPB, LPB+1, or LPB+2 of a long loop.

7-54

SC140 DSP Core Reference Manual

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Freescale Semiconductor SC140 specifications Lpmark Rule L.L.2, Lpmark Rule L.L.3, Lpmark Rule L.L.5