Tony Nixon wrote:
>
> Sean Breheny wrote:
>
> >Rotate a value without using carry.
> >
> > >rlf RAM,w
> > >rlf RAM
> >
> > I'm afraid I don't get this one. Why isn't carry affected? In fact, if it
> > weren't affected,the first line would do nothing to affect the second.
>
> It does 'affect' the carry, but it doesn't 'use' it.
> In other words rotate the byte left once.


If you would like to rotate without affection the carry you can do it like that:

;right cycle shift

rrf     RAM,W
rrf     RAM,F
addlw   0x80    ;restore carry

;left cycle shift

rlf     RAM,W
rlf     RAM,F
movwf   temp_cy
rrf     temp_cy,f ;restore carry

Any ideas how to make second one shorter ? ;-)

WBR Dmitry.