ARMv4 vs ARMv6

Koen Kooi k.kooi at
Thu Oct 16 15:31:41 CEST 2008

Op 16 okt 2008, om 15:02 heeft Andy Green het volgende geschreven:

> Hash: SHA1
> Somebody in the thread at some point said:
> | I don't know the details of ARMv4/v6/VFP interaction, but I  
> believe it is
> | all the same ABI (EABI), and you should very well be able to link  
> a ARMv6
> | application against an ARMv4 library.
> It comes down to the same thing though in packaging.  If someone
> bothered to build an ARMv6-specific mplayer binary for example, so  
> they
> can squeeze out 1 more fps, they are going to build it to "require"  
> all
> the ARMv6 libs mplayer likes, eg ffmpeg and aac stuff.

It wouldn't 'require' armv6 libs, it would still work fine if you  
install the armv6 mplayer with only armv4t libs in the rootfs. And  
FWIW, I expect mplayer to run approx. twice as fast when compiled with  
armv6 since ffmpeg has seen a lot of optimization for armv6 (and  
And more importantly: mplayer has an internal copy of ffmpeg, so your  
example doesn't fly.

>  You might have
> something else installed on the same box that required the v4 ones  
> too,
> so the /usr/lib and /usr/lib64 type thing is needed for same library /
> different arch coexistence on one system.  It is like the i386 /  
> x86_64
> multiarch situation.

As Harald, Graeme and I said before: no, it's not like that

> Like I said I am sure all of this can be handled, but I am equally  
> sure
> it isn't going to "just work" without care taken in the toolchain and
> distro ends, and it's the kind of thing that needs to be right from  
> the
> start.

It already "Just Works(TM)" in OE and Angstrom, so no problem there.  
There *might* be problems when people want to build *packages* only
using the toolchain, but those people get what they asked for.

> Anyway it sounds like the feel is that we do not ignore it and stick
> with ARMv4 all over, so at least we know what we are headed towards  
> now
> and can start dealing with it.

> - -Andy
> Version: GnuPG v1.4.9 (GNU/Linux)
> Comment: Using GnuPG with Fedora -
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> EXsAnipmg71N5Du6473GJll2Mwo9xLVf
> =II78

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