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Re: _fpstate_fxsave & al
- To: Mark Kettenis <kettenis at wins dot uva dot nl>
- Subject: Re: _fpstate_fxsave & al
- From: Gareth Hughes <gareth at precisioninsight dot com>
- Date: Thu, 08 Jun 2000 01:35:51 -0600
- CC: gdb at sourceware dot cygnus dot com
- References: <200006061357.PAA09891@landau.wins.uva.nl> <393E5832.firstname.lastname@example.org> <200006071241.OAA10825@landau.wins.uva.nl>
Mark Kettenis wrote:
> Okay, I've thought about this and rather than try and change GDB I'll
> just add the PTRACE_GETXMMREGS (which will be defined to the same as
> PTRACE_GETXFPREGS) request and the corresponding core dump note (again,
> defined as NT_PRXMMREG/NT_PRXFPREG).
> Great, although I still think that XFP is more appropriate than XMM.
I guess this is probably the most minor of the discussion points, and
I'll be willing to concede on it if we have nice SSE debugging support
> If it's not too much trouble please send in the patches. I might not
> use them as is, but I might get some useful idea's from them.
Okay, will do.
> - XMM registers shouldn't be displayed with an 'info registers' command.
> Sounds reasonable, but they should be shown by `info all-registers',
> and there should be something like `info simd-registers', to display
> the XMM registers. We should be careful in choosing the name for this
> command. It might be desirable to use the same command to display
> similar registers on other targets (PPC Altivec comes to mind), in
> that case the name shouldn't be too Intel-specific.
My thoughts exactly. The way I've implemented it includes them in the
'info all-registers' command, and I was planning on adding an 'info
simd-registers' or 'info simd-float' command as an experiment.
> - XMM registers should be displayed with either an 'info float' or 'info
> simd-float' or similar command. They should be in a format similar to
> the 5.0 FP registers, with status/control register info and IEEE float
> info (NAN, Inf etc).
> I'd rather not add them to `info float', since its output would
> probably be too long to fit on one screen on a 25-line terminal. But
> `info simd-float' sounds fine.
My thoughts exactly. 'info simd-float' it is then.
> What do you think? The points about binary compatibility with PEEKUSER
> etc are important, and I guess I can live with two PTRACE options if it
> is the sanest way to do things.
> Sounds fine. Yes we really need the two PTRACE requests.
Yes, I agree :-) The more I think about it the more I like the fact
that two PTRACE requests removes the need for any kind of magic number.
This is definitely a Good Thing.
I'm more than willing to help contribute to this work for 5.1, as I want
to ensure the kernel/glibc/GDB support for SSE is done correctly and
robustly. I think we're well on the way to acheiving that.