From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark H Weaver <mhw@netris.org>
Subject: Re: Preliminary 'wip-armhf' branch pushed
Date: Fri, 02 Jan 2015 17:07:26 -0500
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In-Reply-To: <87sifsgb8h.fsf@gnu.org> ("Ludovic
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To: Ludovic =?utf-8?Q?Court=C3=A8s?= <ludo@gnu.org>
Cc: guix-devel@gnu.org

ludo@gnu.org (Ludovic Court=C3=A8s) writes:

> Mark H Weaver <mhw@netris.org> skribis:
>
>> I don't think we need a 'system' for every combination of flags.  We
>> should just find a small number of "sweet spots" in the tradeoff between
>> minimum requirements vs performance.  IMO, for 32-bit ARM, two systems
>> should be enough: armhf, and maybe another one (armel?) that works on
>> lower-end processors.
>
> It=E2=80=99s not even clear that =E2=80=9Chf=E2=80=9D needs to be part of=
 the system name.

I think it needs to be part of the system name, because on ARM these are
two incompatible ABIs.  Among other things, the hard-float ABI passes
floating point arguments in registers.

> In theory, the bootstrap tarballs could be soft-float, which means they
> would run everywhere, and from there users could choose what
> --with-float and --with-fpu flags to use.

A single GCC can generate code for both ABIs, but each ABI uses its own
dynamic linker.  If we did as you suggest, we'd need two separate
bootstrap glibc's, and improve the dynamic-linker-name patching code in
our gcc package to rewrite the two dynamic linker names separately, etc.

     Thanks,
       Mark