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From: Wolfgang Denk <wd@denx.de>
To: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: Mixing hard and soft floating point?
Date: Sat, 17 Oct 2009 21:34:54 +0200	[thread overview]
Message-ID: <20091017193454.7978FF15432@gemini.denx.de> (raw)
In-Reply-To: <OFEC00B9FB.B03AA854-ONC1257652.00644350-C1257652.00651551@transmode.se>

Dear Joakim Tjernlund,

In message <OFEC00B9FB.B03AA854-ONC1257652.00644350-C1257652.00651551@transmode.se> you wrote:
>
> > Recompile and relink it with soft-fp as well. Or ask the provider to
> > do that.
> 
> That is what I am trying do/find out. The supplier claims that
> it should not be a problem and is ATM unwilling to recompile the app/libs.
> I am not convinced won't cause problems, not to mention performance degradation.

If the application is really using FP instructions a lot, then there
is a huge difference between using soft-float and MATH_EMU; I
remember test cases where soft-float was faster by factors of
500...1000.

> OK, but then you don't mix some libs/apps with soft and other
> apps/libs with hard FP?

No, we never tried that. Sounds scary to me.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
The connection between the language in which we think/program and the
problems and solutions we can imagine is very close. For this  reason
restricting  language  features  with  the intent of eliminating pro-
grammer errors is at best dangerous.
               - Bjarne Stroustrup in "The  C++ Programming Language"

  reply	other threads:[~2009-10-17 19:35 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-17 12:14 Mixing hard and soft floating point? Joakim Tjernlund
2009-10-17 18:12 ` Wolfgang Denk
2009-10-17 18:24   ` Joakim Tjernlund
2009-10-17 19:34     ` Wolfgang Denk [this message]
2009-10-18 11:28       ` Joakim Tjernlund
2009-10-18 13:10         ` Wolfgang Denk
2009-10-19  0:57       ` Peter Bergner

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