Hi
Can someone please help me with the asm code for a 16-bit count down loop for a PIC16 processor.
The following code does not count down properly. It exits the loop when both
0Ch and 0Dh are 1.movlw h'FF' movwf 0Ch movwf 0Dh loop decfsz 0Ch goto loop decfsz 0Dh goto loop return
Thanks
Mauritz
Which PIC16 is it?
movlw h'FF' movwf 0Ch movwf 0Dh loop: // Value probed here movf 0Ch, f btfsc STATUS, Z goto turnaround decf 0Ch, f goto loop
turnaround: movf 0Dh, f btfsc STATUS, Z goto exit movwf 0Ch decf 0Dh goto loop
If you place code at the "Value probed here" marker, you'll see the values
FFFF ... FF01 ... FF00 FEFF ... 0001 0000 exit
But do you really need it ? If it's to iterate a fixed number of time without using the counter value, you just need to adjust the constant. Using incfsz might be more efficient. Just place in 0C and 0D (0x10000 - number of iter).
clrf 0Ch clrf 0Dh loop: // Value probed here incfsz OCh goto loop incfsz 0Dh goto loop
Sylvain
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