RE: [patch][5/5] powerpc V2: Add the general support for Embedded Floating-Point instructions

=20

-----Original Message-----
From: Segher Boessenkool [mailto:segher@kernel.crashing.org]=20
Sent: Friday, February 09, 2007 10:40 PM
To: Kumar Gala
Cc: paulus@samba.org; Zhu Ebony-r57400; linuxppc-dev@ozlabs.org
Subject: Re: [patch][5/5] powerpc V2: Add the general support=20
for Embedded Floating-Point instructions
=20

quoted

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I thought we were going to have some general Kconfig option to=20
enable all this?  EMDEDDED_FP_IEEE or something like that

So that users have chance to enable/disable fully IEEE compliance?
Segher
had mentioned this, and it sounds reasonable.

Its alot of code to bring in if you don't care about IEEE=20

compliance.
=20
Yes certainly, and that's important for embedded applications.
=20
My point however is that this should be selectable *per=20
process* at runtime.  Compare to the AltiVec situation (where=20
processes can select (non-)IEEE behaviour by themselves);=20
most tasks do
*not* want IEEE behaviour as it is just too expensive (and=20
not necessary for many applications).
=20
=20
Segher

Sorry for the delaying response since I just came back from vacation.

Agreed with you that the IEEE handler is expensive for processes.  Do
you
think adding a switch to the Kconfig option is not enough?  I'm
wondering how
to make it selectable *per process* at runtime.

Ebony