JoeStrout
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Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 5:13 pm

It appears to be possible to make a distro that uses hardware floating-point instructions, yet uses the soft float ABI. This makes it compatible with JIT compilers, like the Mono and Java runtimes, that assume such an ABI. Indeed, when Raspian was in its infancy, they ran into binaries already built this way:
Unfortunately (for some of us, at least), they went on then to full adoption of the hardfloat ABI, rendering it incompatible with Mono (and Java, and possibly others).

I know there are still distributions out there that don't use the FP instructions at all. Debian Squeeze is one, as is Arch, I believe. But my question is:

Is there any distro which is built to the softfloat ABI, but uses FP instructions? This would let us use whatever JIT compilers we want, while still getting good performance on FP calculations. It'd also be the ideal environment for doing stuff like this, which won't work on hardfloat distros.

Thanks,
- Joe


JoeStrout
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 5:32 pm

Thanks, but I was actually already aware of the other thread I started in the Raspbian forum. :)

Let's assume for the moment that we can't talk the Rasbian folks into changing their build settings. Then the question remains:

Is there any Linux distro that uses hardware floating point instructions, but the soft-float ABI?

Cloudcentric
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 5:44 pm

What is the point of responding ?
Last edited by Cloudcentric on Mon Mar 11, 2013 10:36 pm, edited 1 time in total.
I know everything about nothing"

JoeStrout
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 6:54 pm

Cloudcentric wrote:My answer would be rather than making posts and hijacking/spamming other threads, is it 4 so far ?, to get your points across, would be to create you own Distribution !
Whoa! I'm not spamming or hijacking threads. I've tried to be very topical, and as restrained as I can bring myself to be. :)

And yes, I am considering making my own distribution if there is none already configured this way. If there is one already considered this way, then I don't want to add to the confusion by creating another one. I don't know how to find out whether there's one configured this way, except to ask. Thus, this thread where I'm asking exactly that.

Thank you for the ArmEabiPort, though — I hadn't seen that, and it looks quite useful.
I believe that as the majority of Linux Development is undertaken gratis, we have no right to complain when it does not suit are needs, if you can not develop stay quiet !
Goodness, no need to be rude. I have a problem (that many others have also run into), and I'm calmly and politely looking for solutions. And don't worry — it appears that the solution space is nearly exhausted, and there will be no more for me to say about it. And at least the next poor sap who runs into this issue will have the new wiki page to save him some trouble (and save you from repeating yourself).

jamesh
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 7:38 pm

Cloudcentric wrote:
JoeStrout wrote:Thanks, but I was actually already aware of the other thread I started in the Raspbian forum. :)

Let's assume for the moment that we can't talk the Rasbian folks into changing their build settings. Then the question remains:

Is there any Linux distro that uses hardware floating point instructions, but the soft-float ABI?

My answer would be rather than making posts and hijacking/spamming other threads, is it 4 so far ?, to get your points across, would be to create you own Distribution !

http://wiki.debian.org/ArmEabiPort


I believe that as the majority of Linux Development is undertaken gratis, we have no right to complain when it does not suit are needs, if you can not develop stay quiet !
I agree with OP - unnecessarily rude post. Please do not assume everyone knows as much as you do. And asking questions is perfectly all right, even if you 'not a developer'.

It's the moderators job to make sure things stay on track, please remember that.
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Spid
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 8:22 pm

+1 for Cloudcentric
Last edited by Spid on Mon Mar 11, 2013 10:39 pm, edited 1 time in total.
I will always assume you are running Raspbian for desktop and Raspbmc for XMBC !

OtherCrashOverride
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 8:52 pm

If you are familiar with the subject matter, the difference between each thread is clear: One is an issue shared with someone, another about wiki content, another about an existing project, and this one about alternatives to that project. Since they all share the same central issue, it may by mistaken as duplication by layman.

The question for this post is valid and one that I would also like to know the answer to:
Is soft-float wheezy compiled with VFP support while using soft-float ABI? Or is floating point emulated?
If the latter, are there any existing distros that *are* compiled with VFP enabled while maintaining the soft-float ABI?

Please note that this question is not an attempt to sneak changes into Raspbian and should not be feared by villagers with pitchforks and/or torches. The question is academic in purpose only.

Cloudcentric
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 8:57 pm

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
Last edited by Cloudcentric on Mon Mar 11, 2013 10:37 pm, edited 1 time in total.
I know everything about nothing"

jamesh
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 9:07 pm

I've read all the posts, they are different enough to be relevant, they were also considerably politer than some of the replies here. Linux has a bad rep for responses like some of the above. That WILL NOT happen here. I WILL take action to prevent people being put off (which is what happened above).

Please keep it polite, and let the moderators do their job.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
“I think it’s wrong that only one company makes the game Monopoly.” – Steven Wright

jamesh
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 9:12 pm

Spid wrote:Jamesh, though you may consider Cloudy responses rude, I do feel that after looking at the posts the OP made, I would call it Hijacking / Spamming.

The OP had no need to post in several posts to make his point, and in my opinion, he should not be allowed to do so.

Also I feel that there is too much thread hijacking in the forum, it seems to be a disease.

So as to Cloudcentic I would say +1

As to OP I feel tlike being rude to him as well

I believe that as the majority of Linux Development is undertaken gratis, we have no right to complain when it does not suit are needs, if you can not develop stay quiet !
It's quite simple, be persistently rude to people, get a ban. The moderators job is time consuming enough without having to sort out nonsense like this.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
“I think it’s wrong that only one company makes the game Monopoly.” – Steven Wright

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jojopi
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 9:21 pm

OtherCrashOverride wrote:Is soft-float wheezy compiled with VFP support while using soft-float ABI? Or is floating point emulated?
Debian armel does not use VFP. It also does not use ARMv6 instructions. It will run on v5 and maybe v4t. But you can compile individual applications to use VFP on it with softfp.

Out of interest, how does Mono handle distributions like Ubuntu that are hard fp only? Even embedded devices are moving to v7, so softfp is clearly going to die out sooner or later.

OtherCrashOverride
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 9:28 pm

I have not used Ubuntu hard-float, but my guess would be they use the hard-float patch mentioned in the other threads since it works out-of-the-box on armv7 hardware which Ubuntu also targets.

OtherCrashOverride
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 9:37 pm

Out of curiosity I did some research into it and it seems that mono is not supported directly by Ubuntu on hard-float arm.

http://mono.1490590.n4.nabble.com/Mono- ... 57617.html

Spid
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Re: Linux distro with softfloat ABI and hardware FP?

Mon Mar 11, 2013 10:40 pm

jamesh wrote:
Spid wrote:Jamesh, though you may consider Cloudy responses rude, I do feel that after looking at the posts the OP made, I would call it Hijacking / Spamming.

The OP had no need to post in several posts to make his point, and in my opinion, he should not be allowed to do so.

Also I feel that there is too much thread hijacking in the forum, it seems to be a disease.

So as to Cloudcentic I would say +1

As to OP I feel tlike being rude to him as well

I believe that as the majority of Linux Development is undertaken gratis, we have no right to complain when it does not suit are needs, if you can not develop stay quiet !
It's quite simple, be persistently rude to people, get a ban. The moderators job is time consuming enough without having to sort out nonsense like this.
whatever................................
I will always assume you are running Raspbian for desktop and Raspbmc for XMBC !

ghans
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Re: Linux distro with softfloat ABI and hardware FP?

Tue Mar 12, 2013 1:07 pm

Thanks jamesh .

@JoeStrout
Keep it up , i'm wishing you best luck in your endeavors ! :)

ghans
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