GS 3.3 Shell.bin disassembly in-progress by Zoinkity at 11:06 AM EDT on May 11, 2010
Thought you might be interested to see partially-annotated disassemblies of most of the GS v3.3 code. They do some very oddball things, like executing right off ROM space. At least part of the port access has already been annotated, and it will be updated sporadically.