[A83] Re: 83p os
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[A83] Re: 83p os
At 19:06 16-4-03 +0100, you wrote:
> > > And how could you achieve this? There is no hardware support for such
> > > features AFAIK.
> > to do a jump is easy... You just load the address you wanna jump to in a
> > register, and the prog-base in another and add before the jump... Or use
> > relative jumps...
>Relocation is not the hard part. I wasn't even thinking about it as a
>problem.
>What about memory variables? Would there be a common area for them at a
>fixed address? That's not exactly the best idea with a multithreaded OS.
>You can't really avoid the modification of the programs. Relative jumps
>simply don't suffice anyway.
>
>When saying "features", I was actually referring to the interrupt part:
>how would you prevent any program from setting IM 2?
If you already change the jumps you can also check that no program has an
IM2 instruction in it. But when you have self modifying code it's very
difficult to check.
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