From: Peter Bergner <bergner@borg.umn.edu>
To: Paul Mackerras <paulus@samba.org>
Cc: linuxPPC Dev <linuxppc-dev@lists.linuxppc.org>,
Mike Corrigan <mikejc@us.ibm.com>
Subject: FP save/restore code in ppc32/ppc64 kernels
Date: Wed, 7 Aug 2002 11:23:02 -0500 [thread overview]
Message-ID: <20020807162302.GA39680@congo.borg.umn.edu> (raw)
Paul,
Can you describe (if you know/remember since a lot of this code has Cort's name
on it) how the FP save/restore code is supposed to work? I'm wondering why we're
clearing the MSR_FE{0,1} bits along with the MSR_FP bit. Is there a reason why
they must be cleared when we clear the MSR_FP bit?
The reason I ask is that someone was running some userland app that explicitly
set the fpscr (using asm) and he got an FP exception even though gdb showed
his MSR_FE{0,1} bits to be zero. This got me looking at the code which seems
to be inherited old ppc32 code. I noticed that you've updated the ppc32, so
before I update our ppc64 code, I'd like to understand more about how this is
all supposed to work.
Peter
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next reply other threads:[~2002-08-07 16:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-07 16:23 Peter Bergner [this message]
2002-08-08 11:46 ` FP save/restore code in ppc32/ppc64 kernels Anton Blanchard
2002-08-08 13:18 ` Anton Blanchard
-- strict thread matches above, loose matches on Subject: below --
2002-08-08 14:01 Mike Corrigan
2002-08-08 22:34 ` Paul Mackerras
2002-08-09 2:09 ` Peter Bergner
2002-08-12 2:38 ` Paul Mackerras
2002-08-12 14:34 ` Peter Bergner
2002-08-14 2:20 ` Peter Bergner
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