const
  FLOAT = 17.123456789;

function DecAcc(x: Extended; accuracy: Integer): Extended;
var
  d: Extended;
  l: Integer;
begin
  if (accuracy > 0) then
  begin
    d := DecRet(x);
    if (d > 0) then
    begin
      l := (Length(FloatToStr(d)) - 2);
      if (accuracy > l) then
        accuracy := l;
    end else
      accuracy := 0;
    d := Pow(10, accuracy);
    Result := (Floor(x * d) / d);
  end else
    Result := Int(x);
end;

var
  i: Integer;

begin
  ClearDebug;
  for i := -1 to 9 do
    WriteLn(FloatToStr(DecAcc(FLOAT, i)) + ' [FLOAT at Accuracy: ' + IntToStr(i) + ']');
end.