Mike Hord wrote :

> Something no one has mentioned, but probably should, considering
> that someone who didn't know the answer to this question may not
> know the fact I'm going to bring up, is:
> 
> You can't (can't can't can't)(mustn't) use these pseudoinstructions
> as follows:
> 
> btfss   BOB, thumb
> skpz   RALPH
> ....
> 
> Intuitively, it looks like if BOB has 'thumb' set, we shouldn't check
> to see if RALPH is zero or not.  In practice, when you assemble this
> code, MPASM (or whatever assembler you're using) is going to
> expand that skpz macro to its constituent code, and you'll be left
> skipping only the first instruction of that macro.

Now, since the SKPZ (and SKPNZ b.t.w) macro only expands to *one*
instruction there is no problem.

Bad example. Read the manual. Some other "pseudo-intructions"
does have this limitation, just as most other multiple-instruction
macros (you can take care of it inside the macro).

> I've heard people say that they don't use pseudoinstructions to avoid
> this kind of pitfall (i.e., getting caught in the "why won't my code
> work" trap, when it LOOKS fine).

Good point. 

Jan-Erik.



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