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.

[Alex Ionescu]

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