Hi Kenny (Kenny Baby), in <75324F18F1@mail1.mcc.ac.uk> on May 27 you wrote:

> Oh yes just remembered, I'm changing some 84 code to run on a 12c509.

Be careful with the RETURN command.  The 12C does not have a RETURN, but
MPLAB (at least my version of it) assembles it to RETLW 0 without notice!