Re: [avr-gcc-list] Using avr-gcc with AVRStudio's simulator

[Paul Shaffer]

Hi,

Thank you for your reply.  Yes, the code below demonstrates
the problem.  After further experimentation, I discovered
that volatile or not, the AVR Simulator watch view works fine
as long as the variables are in the global scope.

Locally scoped variables seem to always have the problem.

In fact, optimization was turned off and debugging was on
in my example.  FYI, here are the compile/link lines:

avr-gcc -g -Wall -mmcu=at90s2313    -c -o demo.o demo.c
avr-gcc -g -Wall -mmcu=at90s2313  -Wl,-Map,demo.map -o demo.elf demo.o

Any other ideas?  Anyone else able to duplicate this?
Maybe this is a bug in the elf-to-extended-coff conversion?

thanks


> > This code, when compiled with avr-gcc 3.3.1 (and using the
> > patched elf-to-extended coff converter), executes fine, but
> > the AVRStudio simulator version 4.08 reports an  "Invalid location"
> > for the variable "unit" in the watch view, stating that the location
> > is at 0xFFFFFFE0 [SRAM].  Of course, the value of the variable
> > can not be viewed.
> >
> > void main(void)
> > {
> >     int unit;
> >     unit = 5;
> > }
>
> Hello Paul and all,
>
> Does the question really concern this simple program? If so, I suspect that
> the compiler optimizes the variable "unit" out since it is not really used 
> to
> anything. What happens if you define it volatile (or turn optimization 
> off)?

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