M68000 Microcode-level emulation

[Nemesis]

A new document has surfaced which provides a major breakthrough with this effort:
viewtopic.php?t=1452

[iggy]

...
The M68000 patents are very thorough -- mind-numbingly so. They include all the nanocode (see US Patent 4,325,121) , somewhat distorted, but nevertheless spot-on. Must be read carefully, though. See also US Patents 4,296,469 and 4,307,445. You'll want to refer to all of these as you analyze the nanocode. (There are a couple other patents, but they're basically rehash of the others.)...

Are there similar patents available for the MC6809?

Actually, what I'd like is something detailing the HD6309, but the MC6809 would be a start.

[Nemesis]

Patents are difficult to track down unless you already know they exist, or at least I find them difficult to track down. I haven't seen this level of documentation for any other processor though, and I doubt very many were ever described in this kind of detail in any public documentation.

[Chilly Willy]

Patents are difficult to track down unless you already know they exist, or at least I find them difficult to track down. I haven't seen this level of documentation for any other processor though, and I doubt very many were ever described in this kind of detail in any public documentation.

Yeah, I'm surprised Motorola's lawyers let them file those patents with so much info. Company lawyers are skilled at either generalizing or obfuscating or flat out removing any info that might allow someone to actually USE a patent. First, it means that even when the patent expires, others still have to practically reinvent the invention to use it, and second, removing specifics and obfuscation allows the patent to be read in a way that covers more than just what was being patented in the first place.