I'm working on a project where ROM space is at an abolute minimum, and I've tried every trick I can think of to squeeze everything in. Unfortunately, I'm still a bit over the limit. Has anyone got a tight routine to subtract a 16 bit number from a 32 bit number. The result is placed back in the 32 bit number. TIA Tony For the beginner.... PicNPoke Multimedia 16F84 Simulator Assembler, and Tutorial. Now with PicNPlay circuit simulator. Plus animated Address Mode Tutor. http://www.dontronics.com/picnpoke.html