Setting an SSE register to a certain value

Setting an SSE register to a certain value

[Guillaume POIRIER]

Hello,

I'm trying to find a solution to set an XMM register to a certain value.

I've tried
set $xmm2 = 0x000000000000000000000000FFFFFFFF
but I get the error message: "Invalid cast."
and I also tried:
set $xmm2 = (unint128) 0x000000000000000000000000FFFFFFFF
but I get the message the message "No symbol "uint128" in current context."

I've googled around and dig the mailing without finding a solution to
this problem.

I'm using GNU gdb 6.3-debian on and x86 platform.

If someone has the solution to my problem, I'd really appreciate to hear it.

Regards,
Guillaume
--
Life is pleasant. Death is peaceful. It's the transition that's troublesome.
    Isaac Asimov (1920 - 1992)

Re: Setting an SSE register to a certain value

[Jim Blandy]

On 12/27/05, Guillaume POIRIER <poirierg@gmail.com> wrote:
> I'm trying to find a solution to set an XMM register to a certain value.
>
> I've tried
> set $xmm2 = 0x000000000000000000000000FFFFFFFF
> but I get the error message: "Invalid cast."
> and I also tried:
> set $xmm2 = (unint128) 0x000000000000000000000000FFFFFFFF
> but I get the message the message "No symbol "uint128" in current context."
>
> I've googled around and dig the mailing without finding a solution to
> this problem.

If you say "print $xmm", don't you get a structure type?  GDB is
complaining that it doesn't know how to convert the 128-bit constant
you wrote to the register's structure type.  Try assigning to the
individual elements of one of the structure's members.

Re: Setting an SSE register to a certain value

[Eli Zaretskii]

> Date: Tue, 27 Dec 2005 16:15:59 -0800
> From: Jim Blandy <jimb@red-bean.com>
> Cc: gdb@sources.redhat.com
> 
> On 12/27/05, Guillaume POIRIER <poirierg@gmail.com> wrote:
> > I'm trying to find a solution to set an XMM register to a certain value.
> >
> > I've tried
> > set $xmm2 = 0x000000000000000000000000FFFFFFFF
> > but I get the error message: "Invalid cast."
> > and I also tried:
> > set $xmm2 = (unint128) 0x000000000000000000000000FFFFFFFF
> > but I get the message the message "No symbol "uint128" in current context."
> >
> > I've googled around and dig the mailing without finding a solution to
> > this problem.
> 
> If you say "print $xmm", don't you get a structure type?  GDB is
> complaining that it doesn't know how to convert the 128-bit constant
> you wrote to the register's structure type.  Try assigning to the
> individual elements of one of the structure's members.

That is, try this:

  set $xmm2.uint128 = 0x000000000000000000000000FFFFFFFF

Re: Setting an SSE register to a certain value

[Guillaume POIRIER]

Hi,

On 12/28/05, Eli Zaretskii <eliz@gnu.org> wrote:
> > Date: Tue, 27 Dec 2005 16:15:59 -0800
> > From: Jim Blandy <jimb@red-bean.com>
> > Cc: gdb@sources.redhat.com
> >
> > On 12/27/05, Guillaume POIRIER <poirierg@gmail.com> wrote:
> > > I'm trying to find a solution to set an XMM register to a certain value.
> > >
> > > I've tried
> > > set $xmm2 = 0x000000000000000000000000FFFFFFFF
> > > but I get the error message: "Invalid cast."
> > > and I also tried:
> > > set $xmm2 = (unint128) 0x000000000000000000000000FFFFFFFF
> > > but I get the message the message "No symbol "uint128" in current context."
> > >
> > > I've googled around and dig the mailing without finding a solution to
> > > this problem.
> >
> > If you say "print $xmm", don't you get a structure type?

Yes, I do.


> > GDB is
> > complaining that it doesn't know how to convert the 128-bit constant
> > you wrote to the register's structure type.  Try assigning to the
> > individual elements of one of the structure's members.
>
> That is, try this:
>
>   set $xmm2.uint128 = 0x000000000000000000000000FFFFFFFF

Thanks you so much! That worked beautifully. I hope this information
can be added to your documentation as this will probably come in handy
to other people, don't you think? :-)


Guillaume
--
Life is pleasant. Death is peaceful. It's the transition that's troublesome.
   Isaac Asimov (1920 - 1992)