Re: [hatari-devel] Tracing constraints

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 21/11/2023 à 16:45, J.Young a écrit :
> Is it possible to exclude exceptions from trace output?  When examining 
> the trace, the interrupt routines tend to obfuscate things being as they 
> pop in right in the middle of normal code.
>
> On the flip-side, can only exception code be traced?  That would be good 
> in certain circumstances.

Hi

no it's not possible for both cases becauses apart from the cpu jumping 
to an exception vector, you can't really differentiate "normal" cpu code 
from code running from an exception.

also exceptions can be nested which would make thing even harder to split

and some exception can also bypass the rte and jump directly to the 
calling code by messing with the stack content and use rts for example. 
That's not the normal use case, but all in all I don't see how to do a 
simple algo to do this.

the complex algo would be to detect changes in PC value and to ignore 
(or not) all traces until the PC is back to just after what it was 
before being changed. That would require tracking a lot of changes and 
some more complex code if you want to deal with nested cases.

Nicolas