>
> msullivan@vax.niobrara.com (Mark K Sullivan) wrote:
>
> > Using the 16C5x (no ADDLW instruction), can anyone figure out how to form
 the
> > 2's complement of W without using a file register?  And I don't mean a
 look-up
> > table ;)
>
> Maybe it's too early in the morning, but what's wrong with
>
> xorlw   0xFF
> addlw   1

I guess it must have been to early in the morning (5x--no addlw).

Depending upon what you mean by "without using a file register", how about:

        addwf 31,w      ; w = f+w
        subwf 31,w      ; w = f-(f+w) = -w