Apparently, On Fri, May 31, 2002 at 05:49:59PM -0700,
Julian Elischer said words to the effect of;
> interesting but not exactly brief.. :-)
>
>
> On Fri, 31 May 2002, Jake Burkholder wrote:
>
> >
> > The system call stubs in libc are leaf functions; basically just a
> > trap instruction followed by a return. They do not touch the stack
> > at all, or change the stack pointer. One of the first few instructions
> > on entry to the kernel is a save, which rotates the register window
> > and logically saves the call-safe registers onto the user stack
> > (the outs become the ins, and the kernel gets new ins and locals,
> > with the old ones being saved to the user stack once a flush is
> > performed or they get spilled out).
>
> the question is "when does it switch to the kernel stack?"
> (and back?)
This is not done by the hardware. Its done by the trap code after
the save is executed.
>
>
> >
> > Here is a reference: http://www.sparc.com/standards/v9.ps.Z
>
> downloaded... 300+ pages.. hmm.
>
>
> >
> > Jake
> >
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