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RE: gcc-2.95.2 problem with target powerpc-eabi
- To: "David Korn" <dkorn at pixelpower dot com>
- Subject: RE: gcc-2.95.2 problem with target powerpc-eabi
- From: "Christoph Hirzel" <hirzel at indel dot ch>
- Date: Thu, 26 Oct 2000 14:42:56 +0200
- Cc: <gcc-help at gcc dot gnu dot org>
- Reply-To: <hirzel at indel dot ch>
In our kernel I can create tasks with floating point enabled or
disabled. If I don't need floating numbers in a task I disable them
to improve task switches (much faster because the kernel doesn't
have to save/restore the 32 floating point registers of the PPC603).
So my problem is if I work with 64 Bit integers or stuctures in a
task with floating support disabled this task stops with a floating
point exception.
Christoph
-----Ursprüngliche Nachricht-----
Von: David Korn [mailto:dkorn@pixelpower.com]
Gesendet: Donnerstag, 26. Oktober 2000 13:29
An: 'hirzel@indel.ch'; gcc-help@gcc.gnu.org
Betreff: RE: gcc-2.95.2 problem with target powerpc-eabi
>From: Christoph Hirzel [mailto:hirzel@indel.ch]
>Sent: 26 October 2000 07:45
>There seems to be a problem in copying 64 Bit integers
>or structures with gcc-2.95.2 for target powerpc-eabi.
> lis 11,u1@ha
> la 9,u1@l(11)
> lis 10,u2@ha
> la 11,u2@l(10)
> lfd 0,0(11)
> stfd 0,0(9)
>
>The compiler seems to optimize the copy by using load (lfd)
>and store (stfd) double float instructions.
Can I enquire *why* this is a problem? I have the impression (stop me
if I'm wrong) that lfd/stfd will do a straight load/store between the
fpregs and memory, without any messing around with rounding or format
conversion or anything like that.
DaveK
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