[fpc-devel] Optimizations

[Martin Frb]

On 24/01/2014 01:03, Martin Frb wrote:
>
> Until that is done, your best choice, if you need the speed is to do 
> this by hand:
>
>
> or better
> if cnt = 0 then exit;
> tmpptrA := @a[0];
> tmpptrB := @b[0];
> for i := 0 to cnt - 1 do
>     begin
>       tmpVAlue := tmpptrA^ + tmpptrB^;
>       tmpptrA^ := tmpVAlue;
>       inc(tmpptrA); // assuming a typed pointer
>       tmpptrA^ := tmpVAlue;
>       inc(tmpptrB); // assuming a typed pointer
>     end;

Actually, if the late hour has not clouded my sight, it goes even better.

tmpptrA := @a[0];
tmpptrB := @b[0];
  tmpVAlue := tmpptrA^;
for i := 0 to cnt - 1 do
     begin
       tmpVAlue := tmpVAlue + tmpptrB^;
       tmpptrA^ := tmpVAlue;
       inc(tmpptrA); // assuming a typed pointer
       inc(tmpptrB); // assuming a typed pointer
     end;
     tmpptrA^ := tmpVAlue;

the last is actually a[cnt], not sure if intended, but it is done so in 
the original code too.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freepascal.org/pipermail/fpc-devel/attachments/20140124/538a37e4/attachment.html>