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Re: [MiNT] update:WRITE_BOOT,ALLOW_TRP_CHG



Peter Persson, 04.10.2012 12:35:48:

2012/10/4 Helmut Karlowski <helmut.karlowski@ish.de>:
It is Setexc, not Ssystem (been too long when I implemented this). Ssystem
is used to change the behaviour of Setexc.

Hmm... could you elaborate this a bit? Ssystem() offers stuff like
S_SETLVAL/S_GETLVAL to read the supervisor protected area, and so does

Right - did not know about these. But it only allows to change addresses between 0x420 and 0xfffc. I guess the traps are below 0x420, so either this needs another treatment or could be handled by ALLOW_TRP_CHG? Not sure.

So how does Ssystem() change the behavior of Setexc()? Is this something new?

Ssystem(S_ALLOW_TRP_CHG, arg, 0);

will change the behaviour of Setexc (allow or not, depending on arg).

There will be another patch for XaAES where it can be activated by XaAES so
any dirty prgs run before XaAES won't be affected.

Probably a good idea, since "dirty" is often "the cleanest possible
way to do it" on this platform, since we lack APIs & proper mechanisms

I cannot imagine a situation where it is possible to change the traps in serious usage.

for... well... most stuff. Still I think it's a good idea to make it
possible to restrict these things, as long as it is optional for the
user.

Stabilize it!

--
Helmut Karlowski