Re: [ros-dev] [ros-diffs] [tkreuzer] 44464: [RTL] Rewrite the rtl bitmap implementation. The old one was a little .... suboptimal. The new one should outperform the old one by several orders of magnitude, especially RtlFindClearBits that was literally searching bit by bit.

Mon, 07 Dec 2009 20:07:12 -0800 

So? Use intrinsics anyways.

Or __builtin_clz...

On 2009-12-07, at 10:07 PM, Timo Kreuzer wrote:

> 
> Because this is a host module.
> 
> Alex Ionescu wrote:
>> Well why this then? They should be intrinsics...
>> 
>> On 2009-12-07, at 8:43 PM, Timo Kreuzer wrote:
>> 
>> 
>>>>> +unsigned char BitScanForward(ULONG * Index, unsigned long Mask)
>>>>> +{
>>>>> +    *Index = 0;
>>>>> +    while (Mask && ((Mask & 1) == 0))
>>>>> +    {
>>>>> +        Mask >>= 1;
>>>>> +        ++(*Index);
>>>>> +    }
>>>>> +    return Mask ? 1 : 0;
>>>>> +}
>>>>> +
>>>>> +unsigned char BitScanReverse(ULONG * const Index, unsigned long Mask)
>>>>> +{
>>>>> +    *Index = 0;
>>>>> +    while (Mask && ((Mask & (1 << 31)) == 0))
>>>>> +    {
>>>>> +        Mask <<= 1;
>>>>> +        ++(*Index);
>>>>> +    }
>>>>> +    return Mask ? 1 : 0;
>>>>> +}
>>>>> 
>> 
>> Best regards,
>> Alex Ionescu
>> 
>> 
>> _______________________________________________
>> Ros-dev mailing list
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>> http://www.reactos.org/mailman/listinfo/ros-dev
>> 
>> 
> 
> 
> _______________________________________________
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Best regards,
Alex Ionescu


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