On 2010-08-11 17:29, Wouter van Ooijen wrote:
>> I've seen much code written this way and I use this technique all the
>> time when writing my own code.  It works, its efficient, its
>> readable, its maintainable.  What more do you want?
>
> It works, I agree. But I disagree very much with readable, and (as a
> consequence) with maintainable. The fact that the OP had trouble with
> this code is proof that it is confusion, at the very least.
>
> At the moment I am wring a small course on 'propper' programming (in C,
> but that is almost irrelevant). I would qualify a technique like this
> (relying on PORT/TRIs adresses being the same) as a 'last resort': don't
> use it, unless you absolutely must. To quantify it: if you use such a
> technique, write 20+ comment block that explains the technique and why
> it is absolutely necessary to use it. That will deter most
> 'unreasonable' uses.
>
> PS the offending code fragment:
>
>   >>          BANKSEL TRISD
>   >>          movlw   0x00
>   >>          movwf   PORTA
>   >>          movwf   PORTB
>   >>          movwf   PORTC
>   >>          movwf   PORTD
>
> does not benefit from this 'technique' in any way. Using the TRIS
> registers would result in exactly the same code.

Not on the actual processor (an PIC18), does it ?
On a PIC16, yes...


>
> PPS: can you show a piece of code that really benefits from this techniqu=
e?
>
--=20
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