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Re: Does each core of 8-core Intel processor has an independent floating X87 unit?

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Does each core of 8-core Intel processor has an independent floating X87 unit?
Date 2015-04-07 12:48 +0200
Organization A noiseless patient Spider
Message-ID <mg0cja$29d$1@dont-email.me> (permalink)
References (4 earlier) <20150405184015.6382cea4@maxa-pc> <mfrpm1$oui$1@news.albasani.net> <20150405193709.70a12cdf@maxa-pc> <mg03ne$1j1$1@dont-email.me> <s057ialo0uiqmfoksu0j1vn0ed34modgkq@4ax.com>

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On 07/04/15 10:32, Robert Wessel wrote:
> On Tue, 07 Apr 2015 10:16:37 +0200, David Brown
> <david.brown@hesbynett.no> wrote:
> 
>> On 05/04/15 19:37, Melzzzzz wrote:
>>> On Sun, 05 Apr 2015 11:56:13 -0500
>>> BGB <cr88192@hotmail.com> wrote:
>>
>>>>
>>>> Microsoft's compiler treats "long double" as equivalent to "double",
>>>> so 80-bit floats don't really exist on Win64 to begin with, so no
>>>> issue here.
>>>
>>> I think that Microsoft wouldn't break anything like that, and that is
>>> why their long double treats as double. It made them easier to
>>> port to architectures that don't have extended precision float.
>>>
>>
>> MS does not worry much about porting to different architectures.  But
>> they /are/ concerned about code compatibility despite notoriously lax
>> coding amongst windows programmers - thus in Win64 a "long" is 32-bit
>> rather than 64-bit like in most 64-bit OS's, to support code that is
>> written with the assumption that "long" is always 32-bit.  Making "long
>> double" and "double" the same on Windows keeps things easier for
>> programmers who don't pay due care to their types.
> 
> 
> The dropping of 80-bit long doubles came about because MS *was*
> worrying about cross platform issues.  80-bit floats were only
> supported on x86, and MS was definitely intending non-x86 platforms
> for NT.  MIPS, for example, shipped from day one (and was reportedly
> where NT booted the first time).  Along the way they've supported
> Alpha, PPC and (sort-of) ARM.  IPF, too, but that supported the 80-bit
> type.

I did not realise the decision about dropping 80-bit long doubles was
that old.  Yes, MS used to be more interested in portability with
support for different targets, but that's a long time ago (except for
sort-of support for Itanium and sort-of support for ARM and other
Wince/Winphone cpus).

> 
> So the idea was that long doubles would be the same on all platforms.
> I'm not going to defend that approach, but...  At least they could
> have provided an x86-specific extended type, or even intrinsics, for
> people still wanting to use the 80-bit type.   Which is more-or-less
> similar to your argument.
> 
> Win16 versions of MS's language produces certainly supported 80-bit
> long doubles.
>

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Does each core of 8-core Intel processor has an independent floating X87 unit? Weng Tianxiang <wtxwtx@gmail.com> - 2015-04-05 06:50 -0700
  Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Noob <root@127.0.0.1> - 2015-04-05 17:17 +0200
    Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Melzzzzz <mel@zzzzz.com> - 2015-04-05 17:35 +0200
      Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 11:21 -0500
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Melzzzzz <mel@zzzzz.com> - 2015-04-05 18:40 +0200
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 11:56 -0500
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? fir <profesor.fir@gmail.com> - 2015-04-05 10:08 -0700
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 13:17 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 10:10 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-07 10:26 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 23:40 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Bartc <bc@freeuk.com> - 2015-04-07 23:06 +0100
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-08 01:23 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-07 23:15 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-07 20:16 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-08 09:27 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-08 09:44 -0500
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Melzzzzz <mel@zzzzz.com> - 2015-04-05 19:37 +0200
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 18:50 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-05 22:29 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 23:09 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-06 01:54 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-06 07:44 -0500
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 10:16 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-07 03:32 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 12:48 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Richard Heathfield <rjh@cpax.org.uk> - 2015-04-07 11:57 +0100
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 13:33 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-07 15:21 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-04-07 17:15 +0000
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Tim Prince <tprince@computer.org> - 2015-04-07 14:21 -0400
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Keith Thompson <kst-u@mib.org> - 2015-04-05 13:08 -0700
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 15:27 -0500
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Noob <root@127.0.0.1> - 2015-04-05 19:04 +0200
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Melzzzzz <mel@zzzzz.com> - 2015-04-05 19:38 +0200
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? fir <profesor.fir@gmail.com> - 2015-04-05 10:46 -0700
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Keith Thompson <kst-u@mib.org> - 2015-04-05 13:12 -0700
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? fir <profesor.fir@gmail.com> - 2015-04-05 09:51 -0700
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 12:18 -0500
      Re: Does each core of 8-core Intel processor has an independent floating X87 unit? jacobnavia <jacob@jacob.remcomp.fr> - 2015-04-06 01:30 +0200
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 19:27 -0500
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? christian.bau@cbau.wanadoo.co.uk - 2015-04-07 23:58 -0700
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-08 08:08 -0500
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Melzzzzz <mel@zzzzz.com> - 2015-04-06 03:36 +0200
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 10:27 +0200
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-07 10:39 -0500
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? christian.bau@cbau.wanadoo.co.uk - 2015-04-07 23:47 -0700
    Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 11:04 -0500
      Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Melzzzzz <mel@zzzzz.com> - 2015-04-05 18:20 +0200
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-05 11:43 -0500
      Re: Does each core of 8-core Intel processor has an independent floating X87 unit? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-04-05 20:28 +0000
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-04-05 14:46 -0700
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? fir <profesor.fir@gmail.com> - 2015-04-05 15:01 -0700
    Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Keith Thompson <kst-u@mib.org> - 2015-04-05 13:17 -0700
  Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Paul <nospam@needed.com> - 2015-04-05 14:31 -0400
    Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 11:01 +0200
  Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-05 22:34 -0500
    Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Weng Tianxiang <wtxwtx@gmail.com> - 2015-04-05 23:39 -0700
      Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-06 02:06 -0500
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-06 08:57 -0500
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-06 12:38 -0500
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-06 16:30 -0500
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Stephen Sprunk <stephen@sprunk.org> - 2015-04-06 17:10 -0500
                Re: Does each core of 8-core Intel processor has an independent floating   X87 unit? Ian Collins <ian-news@hotmail.com> - 2015-04-07 10:16 +1200
                Re: Does each core of 8-core Intel processor has an independent floating   X87 unit? Melzzzzz <mel@zzzzz.com> - 2015-04-07 02:23 +0200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-06 17:36 -0500
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-06 17:41 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-06 20:09 -0500
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Richard Damon <Richard@Damon-Family.org> - 2015-04-06 22:44 -0400
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? David Brown <david.brown@hesbynett.no> - 2015-04-07 11:11 +0200
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Weng Tianxiang <wtxwtx@gmail.com> - 2015-04-06 08:04 -0700
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-06 12:43 -0500
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Paul <nospam@needed.com> - 2015-04-06 14:52 -0400
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? BGB <cr88192@hotmail.com> - 2015-04-06 17:09 -0500
      Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Paul <nospam@needed.com> - 2015-04-06 11:11 -0400
        Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-06 12:47 -0500
          Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Stephen Sprunk <stephen@sprunk.org> - 2015-04-06 17:15 -0500
            Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Robert Wessel <robertwessel2@yahoo.com> - 2015-04-07 03:41 -0500
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Ian Collins <ian-news@hotmail.com> - 2015-04-07 21:19 +1200
                Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Stephen Sprunk <stephen@sprunk.org> - 2015-04-07 10:37 -0500
                Re: Does each core of 8-core Intel processor has an independent floating   X87 unit? Tim Prince <tprince@computer.org> - 2015-04-07 12:13 -0400
                Re: Does each core of 8-core Intel processor has an independent floating   X87 unit? Stephen Sprunk <stephen@sprunk.org> - 2015-04-09 12:34 -0500
              Re: Does each core of 8-core Intel processor has an independent floating X87 unit? Stephen Sprunk <stephen@sprunk.org> - 2015-04-07 10:48 -0500

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