Xilinx Virtex4 FX PPC
stephen.neuendorffer at xilinx.com
Tue Aug 21 03:50:00 EST 2007
Note that you should pick one or the other and be consistent.
If you have MATH_EMULATION
in the kernel and use code compiled partly with and partly without
then you get really strange errors, because (I believe) the soft-fp uses
a different mechanism for emulating the floating point register files
the kernel (I suppose you'll also see the same thing in a system with
point unit and a mixed-up compilation as well).
> -----Original Message-----
> linuxppc-embedded-bounces+stephen=neuendorffer.name at ozlabs.org
> [mailto:linuxppc-embedded-bounces+stephen=neuendorffer.name at oz
labs.org] On Behalf Of Robert Woodworth
> Sent: Monday, August 20, 2007 10:27 AM
> To: Josh Boyer
> Cc: linuxppc-embedded at ozlabs.org
> Subject: Re: Xilinx Virtex4 FX PPC
> On Mon, 2007-08-20 at 11:35 -0500, Josh Boyer wrote:
> > On Mon, 20 Aug 2007 10:00:54 -0600
> > Robert Woodworth <rwoodworth at securics.com> wrote:
> > > Problem 2: Build my own rootfs.
> > > If I try to build my own programs (busybox and bash at
> this point) with
> > > shared libc using the same glibc from my toolchain, I get
> an "Illegal
> > > instruction" error. Is my glibc not compatible with my
> Xilinx PPC 405??
> > >
> > >
> > > If I try to build a rootfs with debian ppc packages I
> have the same
> > > "Illegal instruction" error.
> > >
> > >
> > >
> > > Question 1:
> > > Do I need a special glibc for the Xilinx PPC 405????
> > > Does a normal PPC glibc have more "advanced" instructions
> compiled in
> > > that will not work on a Xilinx PPC 405??
> > Make sure you're building glibc with soft-fp, or make sure you have
> > CONFIG_MATH_EMULATION enabled in your kernel. The PPC 405
> doesn't have
> > an FPU.
> > josh
> CONFIG_MATH_EMULATION fixed it!!
> What are the opinions out there?
> Kernel fp or glibc soft-fp??
> I don't have a need for floating point in my final application anyway.
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