[Freeciv-Dev] Re: Profiling Civserver again

[Mike Kaufman <mkaufman@xxxxxxxxxxxxxx>]

Perhaps someone could answer this for me: why do we _have_ to assume possible X 
values outside [-map.xsize,2*map.xsize] ? When would this (legitimately) happen?

If a function is (naughtily) setting X too big or small, let's correct the 
function. Grepping through the code, I don't see a massive number of places 
where map_adjust_x() is called. Ought not be that hard to track down. Someone 
please correct my naivete

-mike

On Thu, Aug 02, 2001 at 01:10:51AM +0200, Gaute B Strokkenes wrote:
> On Wed, 1 Aug 2001, vasc@xxxxxxxxxxxxxx wrote:
> > Well does gcc optimize it this way?
> > 
> > #define map_adjust_x(X) \
> >   (((X) % map.xsize) + (((X >= 0) - 1) & map.xsize))
> 
> You mean * rather than &, right?
> 
> > This is faster. Its faster on all CPUs. Notice it doesn't have any
> > branches. Of course its also pretty darn unreadable :-)
> 
> I'm sceptical.  Note that Gregory's patch, which replaced the modulus
> operations with two while loops, doubled the speed of
> normalize_map_pos().  It's too bad that there's no easy way to use
> loop constructs in macros, short of using inline functions instead.
> Perhaps the best thing would be to change it to trigger on
> 
>   (X) < 0 || (X) >= map.xsize)
> 
> instead.  Off course, the proof of the pudding is in the eating:
> Somebody really ought to profile all these different approaches,
> etc. etc.
> 
> -- 
> Big Gaute                               http://www.srcf.ucam.org/~gs234/
> Are you mentally here at Pizza Hut??