From: Dmitry Bely <dmitry.bely@gmail.com>
To: Caml List <caml-list@inria.fr>
Subject: Re: [Caml-list] Re: Ocamlopt code generator question
Date: Tue, 5 May 2009 20:26:01 +0400 [thread overview]
Message-ID: <90823c940905050926t56746bfck4bccfdeb5e7a81a1@mail.gmail.com> (raw)
In-Reply-To: <4A006410.8000205@lexifi.com>
On Tue, May 5, 2009 at 8:06 PM, Jean-Marc Eber <jeanmarc.eber@lexifi.com> wrote:
> Hi Dimitry,
>
> Firstly thanks for looking again at the sse2 stuff!
>
> A difference may occur, if I'm not wrong, from the intermediate results
> precision:
>
> in sse2, eveything is done on 8 bytes (if you "do" doubles at least), while,
> in x87, intermdiate results (kept on the stack) are 10 bytes precision.
>
> This may result in differences (and the bytecode runtime never uses x87
> intermediate storage, so it behaves _numerically_ like the sse2 code
> generator, I guess).
I wouldn't be so sure. Bytecode runtime is C compiler-dependent (that
does use x87 for floating-point calculations), so rounding errors can
lead to different results. Floating point is always approximate...
- Dmitry Bely
next prev parent reply other threads:[~2009-05-05 16:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-28 19:36 Dmitry Bely
[not found] ` <m27i13tofi.fsf@Pythagorion.local.i-did-not-set--mail-host-address--so-tickle-me>
2009-04-29 16:50 ` Dmitry Bely
2009-04-29 20:04 ` Jeffrey Scofield
2009-05-05 9:24 ` [Caml-list] " Xavier Leroy
2009-05-05 9:41 ` Dmitry Bely
2009-05-05 14:15 ` Jean-Marc Eber
2009-05-05 14:58 ` Sylvain Le Gall
2009-05-05 15:21 ` [Caml-list] " David Allsopp
2009-05-05 15:59 ` Dmitry Bely
[not found] ` <4A006410.8000205@lexifi.com>
2009-05-05 16:26 ` Dmitry Bely [this message]
2009-05-05 15:14 ` [Caml-list] " Jon Harrop
2009-05-08 10:21 ` [Caml-list] Ocamlopt x86-32 and SSE2 Xavier Leroy
2009-05-10 11:04 ` David MENTRE
2009-05-11 2:43 ` Jon Harrop
2009-05-11 3:43 ` Stefan Monnier
2009-05-11 5:38 ` [Caml-list] " Jon Harrop
2009-05-10 23:12 ` [Caml-list] " Matteo Frigo
2009-05-11 2:45 ` Jon Harrop
2009-05-11 7:55 ` Dmitry Bely
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