While working on a couple optimization examples for you guys, I realized we have been taught to use "div" to to division when possible over "/". As "div" has been optimized for whole numbers where as "/" was designed to handle both whole numbers and fractions. So, I decided to write a quick and dirty test application to see if this still holds true today. In short, yes on a Mac, no on Linux... here is my test code:
    Download division.pas source

Uses
   dxutil_environment;// contains TimeCounter for Windows, Linux and Mac

Var
   Loop:LongWord;
   StartTime:Comp;
   X:Longint;
   Y:Extended;

Begin
   StartTime:=Trunc(TimeCounter);
   For Loop:=1 to 100000000 do X:=SizeOf(LongWord) div 2;
   System.Writeln(Trunc(Trunc(TimeCounter)-StartTime));
   StartTime:=Trunc(TimeCounter);
   For Loop:=1 to 100000000 do Y:=SizeOf(LongWord) / 2;
   System.Writeln(Trunc(Trunc(TimeCounter)-StartTime));
end.

    Oddly (over 100 million calls), on the Mac OS X div took 199ms and "/" took 520ms. However, on this web server (Linux) the code above takes 332ms for "div" and only 225ms for "/". There are many reasons I can assume of why the drastic difference on the Mac. However, the difference between the Mac and Linux is actually confusing. As I thought, on the Mac is is due to the "Extended" variable type. When I changed that to "real" and ran the code again, the "/" theory only took 392ms. See my next experiment titled fraction variables... I will take this thought to document type(s).

G.E. Ozz Nixon Jr.

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