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Re: [PATCH, MIPS] Add support for CPUs with no FPU

On Mar 13, 2008, at 11:46 AM, Adam Nemet wrote:


FWIW I don't have too much of a problem here myself.

And unfortunately people do use as and even ld directly. as and ld have man
and info pages, are used in the built-in implicit rules in GNU make, etc.

This is unfortunate. Those people should be educated :)

I guess regardless of whether soft-float and singe-float are considered to be
a CPU property or an ABI property, there is already existing practise to add
defaults for either in gas. r4650 is defaulting to single-float and there is
MIPS_DEFAULT_ABI in configure that let you set the default ABI based on the
target. It is probably not as sophisticated as GCC's -with- mechanism from
the toolchain developer perspective but it is *equally* useful from a
toolchain user's perspective.

Needless to say this patch is much less valuable for us if this cannot be the
default for Octeon. The default helps precisely the people who are least
likely to know about the -msoft-float option whereas people who are
knowledgeable enough and decide to use kernel FPU emulation on a soft-float
target are likely to have also learned about -mhard-float.

I still hope we can find a compromise here.

Honestly I'm not happy with this approach. I'd like to see people use the gcc configure
interface to this. That said, if you configure a toolchain for a specific processor then
that processor's weirdnesses (single-float, soft-float, 128bit integer regs) should
go along with it.

Another possibility for your deployment is to just build a generic toolchain and then
have it invoked via shell script that adds on -msoft-float btw :)

But yes, less than ideal.


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