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From: Frank Rowand <frank_rowand@mvista.com>
To: Troy Benjegerdes <hozer@drgw.net>
Cc: frowand@mvista.com, linuxppc-dev@lists.linuxppc.org
Subject: Re: calling giveup_altivec on machine with no altivec!?
Date: Thu, 15 Feb 2001 14:47:58 -0800	[thread overview]
Message-ID: <3A8C5C9E.4C02D1AC@mvista.com> (raw)
In-Reply-To: 20010215163356.Q26702@altus.drgw.net


Troy Benjegerdes wrote:


> > Is it possible that the MSR had the MSR_VEC bit set at some point?  One
> > IBM processor user's manual says "the reserved fields should be written
> > as 0 and read as __undefined__.  This is, when writing to a register with
> > a reserved field, write a 0 to the reserved field.  When reading from a
> > register with a reserved field, ignore that bit."


> In either case, if that's what the IBM manuals say, then the code is
> incorrect and should probably be re-done to check that it's actually
> running on a kernel with an altivec unit. Any suggestions on the best way
> to fix it?

Assuming a CONFIG_ALTIVEC flag (or equivalent) existed, then in processor.h:

#ifdef CONFIG_ALTIVEC
#define MSR_VEC         (1<<25)
#else
#define MSR_VEC         (0)
#endif

-Frank
--
Frank Rowand <frank_rowand@mvista.com>
MontaVista Software, Inc

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2001-02-15 22:47 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-02-15 22:06 calling giveup_altivec on machine with no altivec!? Troy Benjegerdes
2001-02-15 22:20 ` Frank Rowand
2001-02-15 22:33   ` Troy Benjegerdes
2001-02-15 22:47     ` Frank Rowand [this message]
2001-02-15 22:39 ` program exception emulates mfspr PVR Frank Rowand
2001-02-15 22:52   ` Dan Malek
2001-02-15 23:41   ` Mark Hatle
2001-02-15 22:57 ` calling giveup_altivec on machine with no altivec!? Dan Malek
2001-02-18  2:41   ` Troy Benjegerdes

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