[crosstool-ng] ARM EABI problem

[Martin Guy]

On 5/15/08, Yann E. MORIN <yann.morin.1998@anciens.enib.fr> wrote:
> soft-float (VFP? FPA?) support, while C library was built with
>  hard-float VFP support.

Just to clarify how messy it is, there are two concepts: floating
point format and floating point instructions.

Formats: There are two formats for storing FP numbers: Ilittle-endian
IEEE-754 (the same as the rest of world) and the old FPA format, which
is word-swapped IEEE-754 for the original ARM FPU that is so rare it's
mythical.

Instructions: If you compile with hard FPA instructions, it uses that
crazy middle-endian 45670123 format. Portability Bugsville, Arizona.
If you compile using soft-float, or with VFP or Maverick FPU
instructions, it uses 01234567 little-endian IEEE-754.

   M

On 5/15/08, Yann E. MORIN <yann.morin.1998@anciens.enib.fr> wrote:
> Matthias,
>  All,
>
>  On Tuesday 13 May 2008 10:45:33 Matthias Kaehlcke wrote:
>  > the problem was that arm-gcc generates by default EABI code for
>  > armv5t, while the AT91RM9200 is armv4t. the patch provided by martin
>  > resolved the problem.
>
>  Good to know.
>
>  > the kernel and the static hello world were build with the ct-ng EABI
>  > toolchain. as i said above, with martins patch it started to
>  > work. maybe your cpu is armv5t?
>
>  Yes, it _is_ armv5te (xscale). You meant v4, I guess.
>  The real problem was a floating point issue, with mis-matched ABI: compiler
>  was built with soft-float (VFP? FPA?) support, while C library was built with
>  hard-float VFP support. Symptom was that setjmp(3) was not wotrking. Took me
>  10 days to figure out... Sigh...
>
>  Regards,
>  Yann E. MORIN.
>
>  PS. I'm rolling-out a bug-fix release of crosstool-NG tonight for those
>     interested.
>  YEM.
>
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