Re: [hatari-devel] Natfeats doc?

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On 9.9.2021 13.45, Troed Sångberg wrote:
> On Wednesday, September 8th, 2021 at 21:19, Nicolas Pomarède <npomarede@xxxxxxxxxxxx> wrote:
> > So, IMO a specific opcode would be a better alternative solution to
> > trigger the debugger :
> >
> > -   it doesn't require any regs
> > -   it won't alter stack or A7
> > -   we can decide that this specific opcode takes 0 cpu cycle, which
> >      means you can even include some debugger calls from a fullscreen routine
> >      and when you come back from the debugger the video sync is still OK.
> >
> >      Pretty handy if you want to debug fullscreen effects :)
>
> I like this suggestion a lot - and as Nicolas points out, it would be extremely handy when debugging advanced demo effects and protections. It's also extremely easy to communicate how to use :D

Using debug symbols for this has it's own pros
and cons compared to extra instruction, but
either is fine with me.


Nicolas, if you like extra instruction more,
it's better that you add it.  It just needs
to call DebugUI(REASON_CPU_BREAKPOINT).

For now you could make it so that unless NatFeats is enabled [1], it 
triggers exception.

I can later on add specific config / cli option
to enable it, and its own reason for debugger
invocation (e.g. REASON_DEBUGGER_INSTRUCTION).

It would be good if you could modify also
disassembler so that it recognizes this new
instruction (along with the two NatFeats
instructions).


	- Eero

[1] ConfigureParams.Log.bNatFeats