AccuTime Systems in Connecticut offers a number of time & attendance devices which are based on the Intel 8032 and decode a number of barcode symbologies, including code 128. I don't have the phone number handy, but you should be able to do a search in Webcrawler or call old-fashioned information for the Connecticut area.

I've disassembled the code and looked it over (not carefully). Obviously it would be illegal for me to pass you the disassembly, but perhaps you could contact ATS and either ask for the code (not likely that they'll give it to you) or buy one of their low-end models (ATS Model 'E') and ask for 'C' libraries, and then disassemble it yourself.

Their 'C' libraries are pretty awful and poorly documented, but the barcode decoding routines seem pretty robust.

Good luck,
Craig Steiner