[tlbuild] Raspberry fp version (soft/hard float)

[Boris Veytsman]

s> From: simon at getthingsfixed.co.uk
s> Date: Thu, 25 Oct 2012 11:26:59 +0100

> Yup, I agree, it's a bit of a mess.

[...]

> The alternative is a native binary that attempts some FP maths. One
> of the things that alerted me that the armel binaries didn't work on
> armhf was that the maths silently failed (no hissy fit thrown
> exceptions or the like). If one runs the armel texlua on hf wheezy
> it returns silly values. E.g. "local r=1.1 io.write(r)" should write
> "1.1", but it actually writes "0". Could use this as a test. This
> would proof us against somebody having both libs in /lib.


Thanks for a very good summary.

Ok, here is my current understanding of the situation with ARM devices

1.  If the OS does not use FPU natively, the current ARM binaries
    work.

2.  If the OS uses FPU natively, some of them fail (lua is one; I
    guess there could be other like pmxab).  On the other hand,
    binaries compiled for native FPU fail on the OSes that do not use
    FPU.

3.  Presumably only Raspbian uses FPU natively.

4.  We can check whether the device is raspberry.  However, we cannot
    tell reliably whether it has Raspbian or, e.g. standard Debian
    unless we do some tests which will add complexity to the platform
    detection script.

I guess if/when Raspbian becomes a part of official Debian, Debian
folks explain Raspbian developers this is not an acceptable situation:
uname -m on Raspbian must return armv6l-fpu instead of armv6l.  If
this is done before TL 2013 is started, great.  If not, the
(admittedly bad) solution I see is adding an option to tlmgr install
menu: if tlmgr sees arm, it should ask 'do you want raspbian
binaries?' in the 'O' section.  Again, this is not elegant or, pardon
my French, user-friendly.  But it seems to be either this or putting
lua into install-tl.

Comments?

-- 
Good luck

-Boris

"I once witnessed a long-winded, month-long flamewar over the use of
mice vs. trackballs...It was very silly."
(By Matt Welsh)