optimize add and sub

[Patashu]

add/sub has some vestigal weirdness that has the correct functionality, but probably isn't optimal or as simple as possible.

https://bitbucket.org/heldercorreia/speedcrunch/src/9cffa7b674890affcb877bfebc81d39c26b20dcc/src/math/floatnum.c?at=master&fileviewer=file-view-default

• float_add
• float_sub
• _addsub_ordered

[Patashu]

The recent changes to add/sub to improve integer arithmetic (toNumber has a similar but simpler kludge too) have tanked their performance by 4x. Would be nice to either have the correct integer arithmetic while not sacrificing performance, or maybe to have two versions so you pick what you want.

[Patashu]

Transport Defender has a really neat add that I need to check for performance/accuracy.

  public static BigNum operator +(BigNum bn1, BigNum bn2)
  {
    long num = Math.Abs(bn1.Exponent - bn2.Exponent);
    if (bn1.Exponent > bn2.Exponent)
    {
      bn2.Base /= Math.Pow(10.0, (double) num);
      bn2.Exponent += num;
    }
    else if (bn1.Exponent < bn2.Exponent)
    {
      bn1.Base /= Math.Pow(10.0, (double) num);
      bn1.Exponent += num;
    }
    return new BigNum(bn1.Base + bn2.Base, bn1.Exponent);
  }