How to prevent variable going below zero?

[richard]

I do not trust that this may be the case for any PIC though.

its a quick easy test to check, it works on all chips that i tried just make sure the compiler dosn't compress the subtract into a decrement
i var can be byte or word

j=8 
i=6 
while j 
status=1
 i=i-2  ;subtractant cannot be 1 
s=status 
debug 13,10,"status ",bin8 s ,"  i ",    dec i 
j=j-1 
wend

[Ioannis]

Well, thanks for checking out. Wow!

Ioannis