[klibc] Re: [PATCH] klibc

H. Peter Anvin hpa at zytor.com
Sun Jun 4 10:42:39 PDT 2006


David Miller wrote:
>  
>> __arch64__ is ugly; it doesn't say it's a sparc thing.  I have added 
>> -D__sparc_v9__ to the sparc64 MCONFIG file, so I think that's fine.
>>
>> Perhaps the right thing to do is to make this an archconfig.h configurable.
> 
> Please don't do this, I'll explain why.
> 
> Using __sparc_v9__ is incorrect, here is the lowdown on these defines:
> 
> 1) __sparc_v9__ means "-mcpu={ultrasparc*,niagara}" or "-mcpu=v9".
>    Although this is implied by "-m64" it can be used for 32-bit
>    code too.
> 
>    __sparc_v9__ means "using v9 instructions" which does not
>    necessarily mean 64-bit
> 
> 2) "__sparc__ && __arch64__" means 64-bit sparc
> 
> People often get this wrong, and it certainly is confusing.
> 

Okay, how about __sparc64__ then (via -D in the MCONFIG file.)

I did change this particular instance to be a archconfig variable, so it 
doesn't exist (I try very much to avoid architecture-specific #ifdefs in 
bulk code.)

	-hpa



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