[Fwd: [fedora-arm] Activity Day June 10th - ARMv7 F15 hardfp bringup]
jcm at redhat.com
Sun Jun 5 01:45:40 UTC 2011
On Sat, 2011-06-04 at 21:10 -0400, Chris Tyler wrote:
> On Sat, 2011-06-04 at 20:53 -0400, Jon Masters wrote:
> >  We're making a "one time" incompatible ABI switch in F-15 bringup to
> > the "hard float" ABI defined in section 6 of the ARM AAPCS (commonly
> > referred to as the ARM EABI - but that doesn't actually exist as a
> > name). The procedure call standard will be ARM AAPCS vfpv3-d16, as
> > defined in section 6 of that document. Other distros are switching and
> > this will form the basis of any LSB standardization effort later on.
> > Think of v7 and v5 as being different arches, which they are really.
> And to further clarify:
> - This is an addition, not a switch -- the intention is to continue to
> support armv5tel in addition to armv7hl at this time -- Tegra and
> Marvell Kirkwood (including plug computer) devices which do not support
> armv7hl will continue to work with armv5tel.
> - The significant incompatibility is hardfp vs. softfp ABI (moreso than
> v7 vs. v5).
Thanks. Indeed, my separate arch comment is really that v7 (with assumed
hardfp that will be the case in the form of ABI used) and v5 without
hardfp do not use the same ABI calling convention. But for
simplification, I called them "different arches".
We'll keep v5 around. I think longer term, it probably makes sense to
kill it off once people have moved to newer boards/systems (like older
versions of IA32 have been killed off over time). But again, that will
depend on who is using v5, etc. over time.
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