On Fri, 2007-02-23 at 21:01 +0100, Gilles Chanteperdrix wrote:
> Philippe Gerum wrote:
> > On Wed, 2007-01-31 at 01:58 +0100, Philippe Gerum wrote:
> > > Ok, no more distant rumblings about x86_64: a Xenomai port to this
> > > architecture has officially started. A preliminary version of the I-pipe
> > > for x86_64 is now available, which I'm going to use to port the Xenomai
> > > core.
> > Here we are. The following revised I-pipe patch is stable enough to run
> > the Xenomai trunk/ on a 4-way Opteron, and on qemu-x86_64 0.8.2 too:
> > The status of the Xenomai/x86_64 port is as follows:
> > - real-time support in user-space is mostly ok, except the FPU
> > management over the Xenomai domain which is broken beyond all
> > recognition. Gilles, as already discussed, I won't resist to let you
> > bang your head on this wall instead of mine, because 1) this will allow
> > me to switch to the pending issues people have raised on the lists so
> > far, 2) I'm fundamentally evil, 3) the fact that you once did dare
> > rewriting the FPU support for Xenomai/x86 clearly shows that you do have
> > some masochistic tendencies anyway.
> Ok, I will do it. Do you have an URL of a datasheet at hand (since the
> x86 code does not work, there must be some difference) ?
AFAICS, you still have an i387 to deal with. I would rather suspect an
issue with some revised logic in the regular task switching code.
Sidenote: the Xenomai/x86_64 switch code eliminates the "switch-to-self"
issue we discussed recently for x86, and I noticed this would break our
x86 FPU logic doing so, so maybe there is something to dig here. I'll
check this asap.
> By the way, there is a change that I made to the i386 context switching
> routine which I think you should make to the x86_64 one: mark all
> register as output registers, this prevent the compiler from considering
> that the value of a particular register survived the context
Indeed, my clobber list won't help for input registers. Will fix.
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