kleinste Zahl in der Signifikanz

[gammatester]

Schau Dir doch einfachen den Opensource der Amath-Unit an.

Delphi-Quellcode:

{---------------------------------------------------------------------------}
function predd(d: double): double;
  {-Return next representable double after d in the direction -Inf}
begin
  with TDblRec(d) do begin
    if THexDblW(d)[3] and $7FF0=$7FF0 then begin
      {Inf or Nan}
      if (hm and $7FFFFFFF=$7FF00000) and (lm=0) then begin
        {d is +- Inf}
        if d>0.0 then d := MaxDouble;
      end;
    end
    else begin
      {finite number}
      if d=0.0 then begin
        hm := x80000000;
        lm := 1;
      end
      else if d<0.0 then begin
        {d<0: increment significand}
        inc(lm);
        if lm=0 then inc(hm);
      end
      else begin
        {d>0: decrement significand}
        if lm=0 then dec(hm);
        dec(lm);
      end;
    end;
    predd := d;
  end;
end;