Re: Best practice for data encoding?

Harald Alvestrand wrote:
> Ted Faber wrote:
>
> > On Mon, Jun 12, 2006 at 02:11:19PM +0200, Iljitsch van Beijnum wrote:
> >  
> >
> > > The problem with text is that you have to walk through memory and 
> > > compare characters. A LOT.
> > >   
> > That's not where your code spends its time.
> >
> > Run gprof(1).  The majority of time your code spends is spent doing the
> > 2 integer divides per text to integer conversion and in strtoimax
> > (called by fscanf).
> > Multiplying or dividing is the worst thing you can do on a CPU in
> > general.
> Note that CPUs are different; some multiply faster than others, compared
> to the rest of the HW.
>
> And if you really need to, you can optimize... a multiplication by 10,
> for instance, can be done by two left shifts and an addition (a*10 = a
> <<3 + a<<1);
You might not end up with the same set of condition codes at the end,
though...

Joe

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