RE: Xilinx Virtex4 FX PPC

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
soft-fp,
then you get really strange errors, because (I believe) the soft-fp uses
a different mechanism for emulating the floating point register files
than
the kernel  (I suppose you'll also see the same thing in a system with
floating
point unit and a mixed-up compilation as well).

Steve

-----Original Message-----
From:=20
linuxppc-embedded-bounces+stephen=3Dneuendorffer.name@ozlabs.org
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[mailto:linuxppc-embedded-bounces+stephen=3Dneuendorffer.name@oz

labs.org] On Behalf Of Robert Woodworth

Sent: Monday, August 20, 2007 10:27 AM
To: Josh Boyer
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: Xilinx Virtex4 FX PPC
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On Mon, 2007-08-20 at 11:35 -0500, Josh Boyer wrote:

quoted

On Mon, 20 Aug 2007 10:00:54 -0600
Robert Woodworth [off-list ref] wrote:
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quoted

Problem 2:  Build my own rootfs.
If I try to build my own programs (busybox and bash at=20

this point) with

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shared libc using the same glibc from my toolchain, I get=20

an "Illegal

quoted

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instruction" error.  Is my glibc not compatible with my=20

Xilinx PPC 405??

quoted

quoted

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If I try to build a rootfs with debian ppc packages I=20

have the same

quoted

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"Illegal instruction" error.
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Question 1:
Do I need a special glibc for the Xilinx PPC 405???? =20
Does a normal PPC glibc have more "advanced" instructions=20

compiled in

quoted

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that will not work on a Xilinx PPC 405??

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Make sure you're building glibc with soft-fp, or make sure you have
CONFIG_MATH_EMULATION enabled in your kernel.  The PPC 405=20

doesn't have

quoted

an FPU.
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josh

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CONFIG_MATH_EMULATION fixed it!!
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What are the opinions out there?=20
Kernel fp or glibc soft-fp??
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I don't have a need for floating point in my final application anyway.
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