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

[Eric Christopher]

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

> Ping^2.

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.

-eric