On Tue, 18 Jan 2000, Jamie Lokier wrote:
> Richard B. Johnson wrote:
> > > Leave that to the gcc. If it is faster to clear high bit with two
> > > shifts, _gcc_ is the one to decide that. And yes gcc is clever enough
> > > to se things like that. [replacing and 0x7fffffff with shl 1 shr 1
> > > is really no problem].
> >
> > Well it's a problem if it doesn't work.
>
> > int main()
> > {
> > int xxx = 0xffffffff;
> > printf("%d\n", foo0(xxx));
> > printf("%d\n", foo1(xxx));
> > return 0;
> > }
>
> You forgot to use `unsigned int' :-)
Well if it is unsigned (I only have up to version 2.3.39) and
looking through this code doesn't show the construct demonstrated;
I'm sorry for the poor demo. If it is unsigned, why would anyone
try to out-code a AND?
Cheers,
Dick Johnson
Penguin : Linux version 2.3.39 on an i686 machine (800.63 BogoMips).
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