Thanks for the replies I'll be trying out all the examples Speed or memory aren't an issue. It's within an ISR which is entered predictably on a comparatively long time-scale Altering PCL like this is something I do once in a blue moon and I always have a bit of a mental block about it. I'm making a device with a dsPIC and an 18F which talk to each other, and decided to port some of the dsPIC's functions to the 18F, for what now seem to be obvious reasons. A very simple computed branch on the dsPIC turned into an "Ah ah ah, not so fast pal" for the 18F mov PORTB,w0 ;read DIP switch and w0,#0x0f,w0 ;PORTB bits 0,1,2,3 sl w0,#2,w0 ;w0 * 4 bra w0 ;computed branch > only one difference (find it!): Will do Thanks again Joe ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2015.0.5646 / Virus Database: 4293/9157 - Release Date: 02/21/15 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .