[fpc-devel] bounty: FPC based debugger

[Sven Barth]

On 14.09.2011 12:44, Michael Schnell wrote:
> On 09/13/2011 04:52 PM, Hans-Peter Diettrich wrote:
>>
>> It's not the CPU, it's more the MMU which can help in finding changed
>> (global) variables.
> AFAIK, the MMU can not work in byte addresses but just with much bigger
> blocks of data. So it does not seem to help with finding a write access
> to a dedicated variable.
>
> Moreover the MMU programming and interrupts will be consumed by the OS
> and a user space program can't even see it.

But the debugger can ask the OS to write protect a page or to enable a 
page guard (which triggers on write access) and then the corresponding 
signal/exception can be catched. This reduces the checks necessary from 
the complete process memory down to only the page size.

Note: I don't know whether it's implemented like that in any debugger, 
this is just a theory of mine.

Regards,
Sven