Re: [MiNT] Supexec taking one VBL?

[Thomas Reiss <frosties@frosties.org>]

Le mardi 09 septembre 2008 à 11:17 -0400, Lonny Pursell a écrit :
> on 9/9/08 8:10 AM, Miro Kropacek wrote:
> 
> > Oh yes, I'm aware of that. I'd like to find some compromis -- it should be
> > something very easy to implement and what's even more important, totally
> > hidden for programmer who wants to run his app also under TOS. Probably some
> > mintlib call wrapper could do this but question still is what to do with that
> > handlers... For example, on Amiga is quite nicely done -- the OS supports
> > exactly this, you define your function, the parameter it should take when the
> > function is called (the most usable is some pointer), call something like
> > registerMyVblHandlerDefinedByThisStructure() and here we go. It's managed by
> > OS but user can define what he wants.
> 
> Correct me if I'm wrong but amiga has no standardized memory protection for
> quite sometime.  Which leads to my next question, do they even have an MMU
> mapping setup to protect any areas of memory at all?

The Amiga OS never had any memory protection and will never have mainly
because of the message passing stuff - I can't get into more details,
sorry. The MMU is however used by some debugging tools to detect
unexpected memory accesses, etc.
Of course, without any protection, you can access anything and trash
everything you want but the OS provides such nice stuff as described by
Miro that prevents you from banging the hardware.