The 237 supplement mandates that any software passing the usual "new" and "useful" requirements MUST be patentable.
10A Computer programs
(1) A computer program is not an invention and not a manner of manufacture for the purposes of this Act.
(2) Subsection (1) prevents anything from being an invention or a manner of manufacture for the purposes of this Act only to the extent that a claim in a patent or an application relates to a computer program as such.
(3) A claim in a patent or an application relates to a computer program as such if the actual contribution made by the alleged invention lies solely in it being a computer program.
The ONLY thing excluded from patentability is something like a program to fill out your tax form, where the SOLE contribution is that it's software doing it. It rules out "X on a computer" if X is something old, and NOTHING is added to it other than "on a computer".
All the standard software patents, the GIF patent, the RSA encryption, patent, the MP3 and other audio/video codec patents, all contain novel mathematical contributions. The GIF patent contribution is that compresses image data. The RSA patent contribution is a new public-key encryption.
This is a complete and utter loss for programmers. They ruled out a laughable narrow category of blatantly bogus patent claims, and otherwise mandated any software that does anything "novel" and "useful" must be patentable.
It's appalling that such a large segment of the geek community have been completely swindled by it.