Re: armhf multiarch tuple

[Paul Brook <paul@codesourcery.com>]

> Steve McIntyre wrote:
> > They'll be upwardly-compatible (i.e. they'll work on v7), but not in
> > reverse. armhf is explicitly defined to be ARMv7+, using VFPv3-D16 (no
> > Neon). That's standardised across distros too.
> > 
> > There's a chance that some of the armhf binaries might run on v6, but
> > if so it's only by chance and not guaranteed.
> 
> This is in contrast with i386-linux-gnu, where the definition is
> 80386+ and actual binaries from distros and others tend to require
> something more modern like 486+ or 586+.  (In other words, for the
> sake of setting filesystem paths there is no need to be strict about
> the instruction set.)

Except that nobody uses i386-linux any more, so in practice it's exactly the 
same.  Even Debian builds for i486, and most other distros target either i586 
or i686.  The ABI is orthogonal to the ISA[1].  i.e. armv6 v.s. armv7-a (or 
vfpv2 v.s. vfpv3) is no different to i386 v.s. i486 v.s. i686 (or sse2 v.s. 
sse3).

Paul

[1] Generating hard-float compatible code is tricky without VFP, but that's a 
separate issue.