Re: [boost] [GSOC]SIMD Library

Subject: Re: [boost] [GSOC]SIMD Library
From: Domagoj Saric (domagoj.saric_at_[hidden])
Date: 2011-03-30 09:11:05

"Mathias Gaunard" <mathias.gaunard_at_[hidden]> wrote in message 
news:imsv07$67b$1_at_dough.gmane.org...
> I'm not giving you any examples yet, because the high-level SIMD code is 
> undergoing lots of changes recently, and things like sincos (which returns 
> a tuple) are broken when you use the Proto-based interface :(.
> I'll come back to you shortly.

No problem...thanks in advance ;)

ps. I'd be wiling to test/use a lower level interface...

>> ps. does NT2 support SSE1 for single precision floats? Unfortunately
>> this is a must for me (and probably for a lot of people as there are
>> quite a few Athlon XP's around) so I cannot use SSE2+ only libraries
>> like Eigen...
>
> I'm afraid not, it only supports SSE2 and upwards.
> But it could be a nice summer project to add support for SSE1 only...
>
> But seriously, who targets that kind of old CPU? ;)

Actually, I'd say most 'serious' commercial projects that do not by 
themselves require 64bit-era machines to be usable. Athlon XP is a P4 era 
CPU that is/was more powerful and much cheaper than its Intel counterpart 
and it unfortunately lacked SSE2 instructions. You can see here 
http://www.kvraudio.com/forum/viewtopic.php?p=4402655#4402655 one of our 
customers saying that he still has a working P3 setup...A lot of such 
machines are still around and ticking (often as secondary 24/7 
under-the-desk/in-the-attic machines)...
Plus, AFAIK SSE2 does not yield enough gain over SSE1 for many/most single 
precision operations to warrant its 'automatic usage'/exclusion of non-SSE2 
CPUs...

ps. does NT2 provide a way to choose/use multiple instruction sets? 
Important so that one can, for example, detect the level of SSE supported by 
the machine and switch to an appropriate routine...

-- 
"What Huxley teaches is that in the age of advanced technology, spiritual
devastation is more likely to come from an enemy with a smiling face than
from one whose countenance exudes suspicion and hate."
Neil Postman