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From:	CBFalconer <cbfalconer AT yahoo DOT com>
Organization:	Ched Research
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: DS and ESP
References:	<a4rfgu$sbg$1 AT news DOT tpi DOT pl> <a4t25g$nn0$1 AT antares DOT lu DOT erisoft DOT se> <3c727c49 DOT sandmann AT clio DOT rice DOT edu>
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Date:	Tue, 19 Feb 2002 18:53:56 GMT
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Charles Sandmann wrote:
> 
> > That is correct. Unless interrupts are disabled when [code using
> > values below ESP] executes it's extremely broken. And it might be
> > broken even if interrupts are disabled (page fault e. g.).
> 
> If the DPMI provider is done correctly either hardware interrupts or
> even page faults work fine even when the user ESP is invalid.  All of
> these should be handled on the locked 4Kb DPMI internal stack and
> never touch the user stack.  So, it turns out that code isn't broken :-)

Doesn't the interrupt itself to the stack switching code have to
store a return address on the user stack? and maybe the flags
too.  Or is that all in the hardware?

-- 
Chuck F (cbfalconer AT yahoo DOT com) (cbfalconer AT XXXXworldnet DOT att DOT net)
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