[Arm-netbook] RedSleeve - New ARM Linux Distro

Deano Calver deano at rattie.demon.co.uk
Mon Mar 26 11:34:53 BST 2012

Barry Kauler wrote:
>Thumb2 isn't what most non-embedded things target, though. Everything
targets the ARM instructions set. Thumb2 is mainly used for things like Java
that execute intermediate byte code, IIRC. It >replaces the java extensions
that were available on the older ARMs.

Thumb2 isn't a replacement for Javelle (the java opcode acceleration system
ARM toyed with, its still there but basically a no-op these days just for
back compat), Thumb2 allows most instructions in normal usage to use the
smaller opcode format, it's a big improvement over Thumb 1 for general code.
In most cases it reduces code size + i-cache usage a lot. There really is a
good reason not to have it on except for backwards compatible support. 

>> I should add that Ubuntu 12.04 will have ARMv7 hard-float binary
>Sure it will, but those aren't going to include proprietary binary drivers
until the upstream vendors make them available in hard-float variants.
Nvidia certainly don't do that yet, and I suspect most of >the others don't
Hardware blobs are really only important in the desktop arena inho, given
Red Sleeve is an 'enterprise' distro I'd expect most users will be server
users (my main area of interest in ARM at the mo), in that case I won't be
using most hardware blobs unless is for things like crypto, not gonna waste
my precious ram on GPU that I'm not going to use (by the time good OpenCL
drivers exists for ARM GPUs that might be useful for servers I'll have less
hair than I have now!).

I suspect that the armv7 hard float + vfp + thumb2 will become the standard
format for this generation of server ARM distros, with some hard core
distros supporting the older platforms (ala Ubuntu 12 and Debian). NEON is
an interesting one, because most do support it, I wouldn't be surprised if
those chips that don't silently get forgotten about and treated like the
older platforms, NEON is a fairly good vector ISA and will become used a lot
in multimedia apps (even if via asm or instrinsics). Even servers will
likely want the jpeg and mpeg acceleration that will come from its usage


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