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Re: GCC floating point usage
- From: Joel Sherrill <joel dot sherrill at OARcorp dot com>
- To: Mike Stump <mrs at apple dot com>
- Cc: Stefan Bylund <steby at enea dot se>, David Edelsohn <dje at watson dot ibm dot com>, gcc at gcc dot gnu dot org
- Date: Mon, 14 Oct 2002 13:12:59 -0500
- Subject: Re: GCC floating point usage
- Organization: OAR Corporation
- References: <D0E9116F-DF9D-11D6-8E3D-000393941EE6@apple.com>
Mike Stump wrote:
>
> On Monday, October 14, 2002, at 10:10 AM, Stefan Bylund wrote:
> > The reason why I am asking this is because in the OSE RTOS, the kernel
> > will only save the floating point registers for a process at context
> > switch
>
> And this is the same reason that Wind River needs the patch.
RTEMS is in the same boat. Right now, the PowerPC port lies and
considers all tasks are floating point to work around this.
This would be a nice improvement for embedded PowerPC users.
Using -msoft-float is unacceptable for RTEMS applications
because it means that some portions of the single executable
would have to be linked against -msoft-float libraries and others
against hardware float variants.
NOTE: We initially encountered this behavior in gcc doing the
HPPA port. As I recall, the PA port at that time used
the FPU for integer multiplies and tended to do it for indexing
arrays of odd-sized structures.
--
Joel Sherrill, Ph.D. Director of Research & Development
joel@OARcorp.com On-Line Applications Research
Ask me about RTEMS: a free RTOS Huntsville AL 35805
Support Available (256) 722-9985