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From: Jon Smirl <jonsmirl-Re5JQEeQqe8AvxtiuMwx3w <at> public.gmane.org>
Subject: Re: Restricting architectures
Newsgroups: gmane.linux.linaro.devel
Date: Thursday 2nd September 2010 17:17:06 UTC (over 6 years ago)
On Thu, Sep 2, 2010 at 11:56 AM, Arnd Bergmann
> On Wednesday 01 September 2010, Michael Hope wrote:
>> We will try to do no harm to other architectures or earlier ARM
>> versions.  The Thumb-2 routines may be applicable to the Cortex-M and
>> Cortex-R series but we will not optimise for them.
>> I'd like Linaro to state this explicitly in the next round.
>> https://wiki.linaro.org/Linaro1011/TechnicalRequirements
defines a
>> 'Standard ARMv7 Configuration' but there's no higher level statement
>> justifying it, no statement restricting us to it, and it includes ARM,
>> Thumb-2, and Thumb-1.
> I think there are two aspects to this:
> On the one hand, we need to improve the code formost for new CPUs looking
> forward, so the latest generation of shiny high-end hardware is what
> matters the most and needs to be the primary target. Today's high end
> is tomorrow's mainstream, so sooner or later everyone will benefit from
> this.
> On the other hand, I think we need to be relevant and provide code that
> everyone can use. The market today mainly consists of stuff that's not
> the primary focus, like ARM926 or some non-MMU cores. Refusing to do a
> simple fix because it's not relevant for Cortex-A8/A9 will just manage
> to piss off people [1].
> Obviously there has to be a middle ground. We're building the binary
> packages for the configuration Dave mentioned (v7A/Neon), but IMHO
> that shouldn't prevent anyone from rebuilding it with our tool chain
> without having to make significant changes. If there are patches readily
> available for stuff that's not our primary focus (thumb1, non-cortex v7A
> CPUs, vfp without neon, ...), I'd say we should still keep them or
> get them upstream.

As an embedded developer I'd like to see a standardized tool chain for
building on most ARM architectures. There are at least two groups of
users for this tool chain - ARM based PCs and embedded systems. There
are dozens are various tool chain build systems for ARM. Every time I
get a new embedded dev board I have to build yet another ARM tool
chain to match what the accompanying software expects. This is a
significant hurdle to new developers who may not have fast machines.
Some of the people I've worked with needed 24hrs to build a tool
chain. Let's get a standardized tool chain for the older ARM chips
into a distribution to stop this needless proliferation.

>        Arnd
> [1] http://www.joe-ks.com/archives_oct2006/ItsNotMyJob.htm
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Jon Smirl
[email protected]
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