>> I am trying to monitor whether a register value drops below zero when a subtraction is carried out. << Use the C bit. For a more detailed answer send you message using PLAIN TEXT next time (not quoted printable). ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.