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Re: MPC860, MSR initialization
- From: Gary Thomas <gary at mlbassoc dot com>
- To: Jonathan Larmour <jifl at eCosCentric dot com>
- Cc: Radu Cernea <rc at unusus dot com>,eCos Discussion <ecos-discuss at sources dot redhat dot com>,eCos Patches List <ecos-patches at sources dot redhat dot com>
- Date: 04 Mar 2003 22:47:56 -0700
- Subject: Re: [ECOS] MPC860, MSR initialization
- References: <200303042226.OAA00710@friend.incoop.net> <3E65599C.50303@eCosCentric.com>
On Tue, 2003-03-04 at 18:57, Jonathan Larmour wrote:
> Radu Cernea wrote:
> > Hi,
> >
> > I think there is a small problem with the definition CYG_MSR_COMMON in the file
> >
> > …\hal\powerpc\arch\current\src\vectors.S
> >
> > The FP bit should not be asserted for MPC860. See MPC860UM, chapter 5.1.2.3.1.
>
> True. Below patch checked in.
>
While this is true, pedantically, it doesn't seem to matter at all
for any MPC8xx that we've ever run eCos on (and it's been nearly 5 years
now). The patch does make things match the documentation, even if
"real life experience" does not :-)
Note: I checked this and it has no performance difference at all.
My guess is that the bit is simply ignored by the hardware.
--
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Gary Thomas |
MLB Associates | Consulting for the
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http://www.mlbassoc.com/ |
email: <gary at mlbassoc dot com> |
gpg: http://www.chez-thomas.org/gary/gpg_key.asc
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