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]

I'm concerned about code duplication.

Why can't our intrinsic header be used on host machines???

On 2009-12-07, at 11:16 PM, Timo Kreuzer wrote:
> Why should I bother reimplementing the intrinsics yet another time for
> different compilers in host headers? and what about compiling on a
> non-x86 linux machine? This code is portable and serves it's pupose very
> well.
> Or are you seriously concerned about the performance?
>
> Alex Ionescu schrieb:
> > 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
> > > > [e-mail]
> > > > http://www.reactos.org/mailman/listinfo/ros-dev
> > >
> > > Ros-dev mailing list
> > > [e-mail]
> > > http://www.reactos.org/mailman/listinfo/ros-dev
> >
> > Best regards,
> > Alex Ionescu
> >
> > Ros-dev mailing list
> > [e-mail]
> > http://www.reactos.org/mailman/listinfo/ros-dev
>
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Best regards,
Alex Ionescu