Re: hf/sf [Was Re: CVS commit: pkgsrc/misc/raspberrypi-userland]

[Matt Thomas <matt%3am-software.com@localhost>]

On Nov 10, 2013, at 1:39 PM, Alistair Crooks <agc%pkgsrc.org@localhost> wrote:

> On Sun, Nov 10, 2013 at 01:20:41PM -0800, Matt Thomas wrote:
>> Exactly.  with hf, floating point values are passed in floating point
>> registers.  That can not be hidden via a library (this works on x86
>> since the stack has all the arguments).  
> 
> Thanks, I understand.  But...  there has to be a different way of
> doing this that does not require such wholesale changes, especially
> when they were made without discussion.
> 
> + use virtual registers which get mapped onto the real thing, either
> through compilation or JIT

Doesn’t help since there are also FP instructions.

> + optimise for one passing scheme, and translate the other dynamically

We already have a libc_vfp.so for earm which will use real FP
instructions to do the softfloat ops.

> + have both sets of passing conventions in a fat binary, and select
> accordingly

ELF doesn’t really support fat binaries.  

> I'm sure there are way more than I've outlined above, and that others
> have much better ideas than I have.
> 
> At the moment, this has been optimised for the kernel architecture,
> with the userlevel changes assumed to be collateral damage.  Since the
> users are what matters, that needs to be changed.

I strongly disagree with that.  I specifically choose use different machine
arches so that the hard/soft float binary packages would be separate.  
From using soft/hard float userlands on PPC, I already knew that mixing
them was wrong.  

> How do you propose to fix this (interim) mess for pkgsrc?  This is a
> real issue for us, and you should send your proposal to
> tech-pkg%netbsd.org@localhost.

Is it just the multiplicity of arm packages or something else?