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Date: Wed, 15 Dec 2010 22:48:33 +0100
Message-ID: <AANLkTin=GXnLuDZncSL9rWKh5teCQP=3iQB-Rz8zxsnk@mail.gmail.com>
Subject: Re: x86: A fast way to check capabilities of the current cpu
From: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>, Tejun Heo <tj@kernel.org>,
        Pekka Enbeerg <penberg@cs.helsinki.fi>, linux-kernel@vger.kernel.org,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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On Wed, Dec 15, 2010 at 10:39 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> On 12/15/2010 01:30 PM, Miguel Ojeda wrote:
>>
>> In this case it this_cpu_*_test_bit() return an int, but they act as a
>> bool and are used in if()s; where is the catch?
>>
>
> If they aren't, and are stored in a variable for whatever reason, then
> the || form will generate additional instructions to booleanize the
> value for no good reason.

Thanks! I suppose that is the 't' of being "a fast way" ;-)

>
> ? ? ? ?-hpa
>
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