I am being shown the light, I have found the switch and am trying to turn it on WRT DT_INT. My mantra is nothing in the ISR should need any PBP system variables (but I could be wrong there, still trying to figure out what uses them and what doesn't). So all my ISR's are ASM, but using PBP commands ie porta=portb.

As for the context saving, all the 16f1xxx and maybe all the 18's already do it for me. So as long as I deal with BSR life is good. But the ease of not looking up all the PIR.somebodys for the INT query does appeal to me. So like I said, I found the switch to turn the light on.