Re: [PATCH] klibc

From: H. Peter Anvin
Date: Sun Jun 04 2006 - 13:42:34 EST


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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