Thanks, Craig!

You clarified me a lot! My push's and pop's are ok, I think my problem is with call's... using RIDE as a simulator I could observe that the SP was being added by one at the end of the main loop cycle... the "real thing" should overflow relativelly fast...

Because that I'm reinitializing the SP at the beggining of the main loop...

Why my calls are unbalanced? Well, I,m doing a small robot, when it goes forward if the IR sensors that I'm using detect a obstacle an "avoid obstacle" routine is called... I think that if it happens too much somewhere in my code I will have one less pop or ret... I couldn't find where (or when) it happens in the RIDE simulator...

orlando