Re: [PATCH v2 0/10] Tilera (and Linux asm-generic) support for glibc

["Joseph S. Myers" <joseph@codesourcery.com>]

On Tue, 15 Nov 2011, Richard Earnshaw wrote:

> The triplet we've been using internally is based on 'aarch64' as the
> first component; I see no reason why we shouldn't adopt that as the
> standard name, thus aarch64-none-linux-gnu would become the standard
> 'triplet' for Linux.  If I could rewrite history, I'd probably go back

That seems good to me.  (With the possibility of variants such as aarch64b 
to describe a toolchain that's configured to be big-endian by default.)

> and rename the existing ARM port to use aarch32; though obviously
> there's no chance of doing that now.

Just as renaming i386 to ia32 in target triplets wouldn't make sense 
either.

> The ISA is not public yet; some more details will be released in due
> course.  The ABI specs, however, are already downloadable from
> infocenter.arm.com in the usual place.

Thanks, I'll have a look at those.  I see IHI0055A_aapcs64.pdf, 
IHI0056A_aaelf64.pdf, IHI0057A_aadwarf64.pdf, IHI0059A_cppabi64.pdf - is 
it expected analogues to the other parts of the 32-bit ABI will be 
released when ready, or are they all included in those four documents?

> First you have to remember that there's no call-level interworking
> between the 32-bit and 64-bit states: you can only switch states at an
> exception level boundary.  Secondly, although the new ISA is 'ARM
> flavoured' it is very definitely different to the AArch32 (ie ARM and
> Thumb) and I don't expect there will be any attempt to create a new
> 'unified' syntax between the two: the number of cases where you could
> share assembly files is just too limited.

So substantially more different than x86 and x86_64, then (which in turn 
are substantially more different than 32-bit and 64-bit variants of MIPS, 
say, where assembly files really do get shared using macros to abstract 
the differences).

-- 
Joseph S. Myers
joseph@codesourcery.com