Mixing hard and soft floating point?

Wolfgang Denk wd at denx.de
Sun Oct 18 06:34:54 EST 2009

Dear Joakim Tjernlund,

In message <OFEC00B9FB.B03AA854-ONC1257652.00644350-C1257652.00651551 at 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

> 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 at denx.de
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restricting  language  features  with  the intent of eliminating pro-
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