Philip -

I would think that the SWAPF instruction would work nicely if your
example of a four bit shift is representative.  Adding an XORFW with a
mask of 0xF0 will get rid of the high order bits if their not needed.

Steve

Philip Martin wrote:
>
> What I have is an input that reads '11010000' say. What I need to do
> is convert it to '00001101' say.
>
> One route seems to be to RRNCF four times. Would this do the job and
> not affect any other registers?