Thank you for answering.

I'm only using cpf-instructions because I'm in the chapter in my book where they use cpf-instructions, therefore I'm practising it.

And I had another question:

In this subroutin they are using

decf n,f
bnz again

movlw .14
movwf n

again:

decf n,f
bnz again
nop
rlncf n,w
movwf PORTC
RETURN

But instead of

decf n,f
bnz again

can I use

decfsz n,f
goto again

?

Is there any advantage of using bnz instead of decfsz?

 

Both of the loop constructs will do the same thing. Decfsz is the more common one and I think makes the loop code stand out a bit more for readability but its a style thing mainly.
You should use bra instead of goto to save a code word AND becsuse it takes 2Tcyc to skip over a goto and only 1 to skip a bra (at the end of the loop. Its 2Tcyc for either when it takes the loop)

Finally, bz can't jump as far as bra and goto. That's not usually a problem for small loops but if the loop gets too big that bz can't reach tbe top of the loop you're back at decfsz anyway... so I use it from the get go.


Have fun.

 

...Is there any advantage of using bnz instead of decfsz?

There is a huge advantage to using decfsz/bra vs. decf/bnz. Decfsz doesn't muck with the status register. This is extremely useful if you need to test the status of an operation that occurred prior to the conditional.

 

There is a huge advantage to using decfsz/bra vs. decf/bnz. Decfsz doesn't muck with the status register. This is extremely useful if you need to test the status of an operation that occurred prior to the conditional.

Good point.