Delphi测试取商除操作符DIV速度控制台程序

Delphi测试取商除操作符DIV控制台颈椎枕速度程序，欢迎加入Delphi开发局QQ群:32422310

program DivVsMult;

{$APPTYPE CONSOLE}
uses
  SysUtils,
  Windows;
var
  Start,Stop, Start2, Stop2, Freq:int64;
  i : integer;
  t : real;
  CpuSpeed : integer;
begin
  { TODO -oUser -cConsole Main : Insert code here }
  { Cpu Speed fastes cpu = 1 slower => 10
    it's just to determin the number of time to do the loop
    Maxint div CpuSpeed is calculated }
  if ParamCount = 1 then
    CpuSpeed := StrToIntDef(ParamStr(1),1)
  else
    CpuSpeed := 10;
  Writeln('Simple Number division:');
  Writeln('Calculating');
  QueryPerformanceFrequency(freq);
  QueryPerformanceCounter(Start);
  for i:=0 to MaxInt div  CpuSpeed do
    t := i * (1/100);
  QueryPerformanceCounter(Stop);
  Writeln(Format('First Pass Result:  %f',[t]));
   { This is needed because the compiler would optimize,
     and would notice the result of the loop isn't used at all,
     so therefor the result is useless.. so depending on the compiler, it will
     choose what to do with it, this disables that optimization   }
  QueryPerformanceCounter(Start2);
  for i:=0 to MaxInt div CpuSpeed do
    t := i * (1/100);
  QueryPerformanceCounter(Stop2);
  Writeln(Format('Second Pass Result: %15.6f',[t]));
   { This is needed because the compiler would optimize,
     and would notice the result of the loop isn't used at all,
     so therefor the result is useless.. so depending on the compiler, it will
     choose what to do with it, this disables that optimization   }
  Writeln('Done, Results:');
  Writeln(Format('/ 100  Time:  %6.4f seconds'+#13#10+
          '/ 100  Clock: %d ticks'+#13#10+
          '* 0.01 Time:  %6.4f seconds'+#13#10+
          '* 0.01 Clock: %d ticks',
          [(Stop-Start) / freq,
          (Stop-Start),
          (Stop2-Start2) / freq,
          (Stop2-Start2)]));
  Writeln;
  Writeln('Odd Number division:');
  QueryPerformanceCounter(Start);
  for i:=0 to high(i) div CpuSpeed do
    t := i / 556;
  QueryPerformanceCounter(Stop);
  Writeln(Format('First Pass Result:  %15.6f',[t]));
   { This is needed because the compiler would optimize,
     and would notice the result of the loop isn't used at all,
     so therefor the result is useless.. so depending on the compiler, it will
     choose what to do with it, this disables that optimization   }
  QueryPerformanceCounter(Start2);
  for i:=0 to high(i) div CpuSpeed do
    t := i * (1/556);
  QueryPerformanceCounter(Stop2);
  Writeln(Format('Second Pass Result: %15.6f',[t]));
  Writeln(Format('/ 556     Time:  %6.4f seconds'+#13#10+
          '/ 556     Clock: %d ticks'+#13#10+
          '* (1/556) Time:  %6.4f seconds'+#13#10+
          '* (1/556) Clock: %d ticks',
          [(Stop-Start) / freq,
          (Stop-Start),
          (Stop2-Start2) / freq,
          (Stop2-Start2)]));
  Writeln(Format('  (1/556) = %15.14f (approximate)',[1/556]));
//  Readln;
end.