Re: [tip:x86/mce] x86/bitops: Move BIT_64() for a wider use

From: H. Peter Anvin
Date: Wed May 23 2012 - 12:55:40 EST


On 05/23/2012 09:54 AM, Linus Torvalds wrote:
> On Wed, May 23, 2012 at 9:47 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>>
>> Any reason we can't just tell people to use BIT() for a native "unsigned
>> long" type (32/64 bits) and BIT_64() if they really want a 64-bit result?
>
> Well, that's what we're doing now. And it seems to have resulted in
> repeated bugs for architectures where most of the developers run on
> 64-bit machines, but the same code is actually supposed to work on
> 32-bit too (ie x86).
>

Yes, but I fear that this will result in more subtle bugs which will
therefore be even harder to detect and diagnose.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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