[WWWDocs] Deprecate support for non-thumb ARM devices

David Brown david@westcontrol.com
Thu Feb 25 14:16:00 GMT 2016

On 25/02/16 14:32, Stefan Ring wrote:
> On Thu, Feb 25, 2016 at 10:20 AM, Richard Earnshaw (lists)
> <Richard.Earnshaw@arm.com> wrote:
>> The point is to permit the compiler to use interworking compatible
>> sequences of code when generating ARM code, not to force users to use
>> Thumb code.  The necessary instruction (BX) is available in armv5 and
>> armv5e, even though Thumb is not supported in those architecture variants.
>> It might be worth deprecating v5 and v5e at some point in the future: to
>> the best of my knowledge no v5 class device without Thumb has ever
>> existed - but it's not a decision that needs to be related to this proposal.
> Slightly off topic, but related: What does the "e" stand for? Also,
> what does "l" stand for in armv5tel, which is what I usually get --
> little endian?



The "t" is thumb, "e" means "DSP-like extensions", and I suspect the "l"
is a misprint for "j", meaning the Jazelle (Java) acceleration instructions.

> I have no idea if there is an authoritative source for these host
> specifications and cannot find any. config.guess seems to just rely on
> uname -m.

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