From: Paul Gofman <pgofman@codeweavers.com>
To: Pekka Paalanen <ppaalanen@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Subject: Re: [PATCH libdrm 2/2] include: Avoid potentially infinite loop in log2_int().
Date: Fri, 30 Oct 2020 16:07:59 +0300 [thread overview]
Message-ID: <53e2c0c8-edef-ffce-d7ae-f42fd8262000@codeweavers.com> (raw)
In-Reply-To: <20201030130739.0e6770c6@eldfell>
On 10/30/20 14:07, Pekka Paalanen wrote:
> On Wed, 28 Oct 2020 13:06:02 +0300
> Paul Gofman <pgofman@codeweavers.com> wrote:
>
>> Signed-off-by: Paul Gofman <pgofman@codeweavers.com>
>> ---
>> util_math.h | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/util_math.h b/util_math.h
>> index e2fa95f5..f6bbe192 100644
>> --- a/util_math.h
>> +++ b/util_math.h
>> @@ -38,6 +38,9 @@ static inline unsigned log2_int(unsigned x)
>> if (x < 2) {
>> return 0;
>> }
>> + if (x & 0x80000000) {
>> + return 31;
>> + }
>> for (l = 2; ; l++) {
>> if ((unsigned)(1 << l) > x) {
>> return l - 1;
> Hi,
>
> I guess that does it, but it seems quite a lot of code that could be
> a two-liner:
> http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogObvious
>
>
> Thanks,
> pq
Hello,
thanks, I've sent the updated patches with simplified implementation.
Regards,
Paul.
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prev parent reply other threads:[~2020-10-30 13:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-28 10:06 [PATCH libdrm 1/2] include: Factor out log2_int() function Paul Gofman
2020-10-28 10:06 ` [PATCH libdrm 2/2] include: Avoid potentially infinite loop in log2_int() Paul Gofman
2020-10-30 11:07 ` Pekka Paalanen
2020-10-30 13:07 ` Paul Gofman [this message]
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