topic Re: RTS returns to wrong place in CodeWarrior for MCU

RTS returns to wrong place

Vickyg — Sun, 23 Dec 2007 15:37:42 GMT

Hi, I'm a newbie to assembler. I've been tracing through my code trying to discover what is happening, and I've found that my RTS is returning to the wrong place. Can anybody shed any light on a situation like this?

Thanks

Re: RTS returns to wrong place

kef — Sun, 23 Dec 2007 17:06:27 GMT

Is stack pointer (SP) pointing to RAM?

Re: RTS returns to wrong place

CompilerGuru — Sun, 23 Dec 2007 19:41:15 GMT

other things to check too
- stack is aligned, all the bytes added in the function have been removed before the RTS
- nothing in the function overwrites the return address
- the caller is using a JSR/BSR (and not CALL, for example)
- the stack is in RAM (as kef noted)
- the stack is allocated large enough.

Daniel

Re: RTS returns to wrong place

Vickyg — Sun, 23 Dec 2007 21:17:00 GMT

Thank you both for your time and effort. Just knowing that there were people out there on my side (me against the chip) was what I needed to get past my problem. It turned out that I had changed chip sets and had missed that the add hx to a routines had moved and I was jumping in one point past where the stack pointer was incremented. Stupid error on my part, but as a complete novice I was sure it was something like an overrun of the stack bounderies.

Thanks, your being there was very important to me.