Ultrascreen100, for the NEC!
Don't you love it when things that start out as a "tiny" possibility has turn into an almost *definite* probability?
That's precisely what happened when I started on this Ultrascreen for the NEC project. I'd gotten a hold of the Ultrascreen100 software by Ultrasoft Innovations. You might remember that this software enables a 60 column by 10 line display and your Model 100s screen, and automatically becomes active as you enter all five ROM programs. As I was playing around with it on my M100, I started having these aspirations of seeing something similar running on my NEC. I figured I'd disassemble the .CO file and check things out.
Well, "things" got complicated rather quickly. Self modifying code, jump tables, and tons of hooks that I'd not seen used before in .CO's that I'd examined. Plus, it turned out that less than *half* of the calls that Ultrascreen made into the Model 100's ROM had equivalents in my M100/NEC cross reference.
I knew that any attempt at conversion was going to involve spending many hours inside disassemblies of the M100 & NEC ROMs investigating the calls and code paths being taken. But that's okay, I was up for a Winter project...and possibly a Spring, Summer and next Autumn project...and maybe yet another Winter project before I could see this thing running on my NEC PC-8201.
But then, wouldn't you know, a fortunate series of events made matters a little nicer. I'd stumbled upon Ultrasoft Innovations website. WHAT? They're still around? Yes indeed they are! Of course, they have nothing to do with Model 100s anymore, but the original proprieter, Richard Eckerlin, still runs a business under that company name that is involved in recycling old computer technology.
I contacted him to find out if there was even the slightest chance that the source code for their original product was still in existence. He responded! Turns out he didn't have the source code himself, but he was able to point me to Daniel Born, the original author. He wasn't sure if the email address he had for Daniel was still valid but as much would have it, it was!
Now Daniel didn't have source code immediately available but he volunteered his time to assist with this effort. A few email conversations later, and Daniel is helping me with transforming my disassembly of the Ultrascreen code into a true assembly file that can eventually be compiled & run on the NEC. There are a few differences in the LCD code between the ROMs that do need special consideration, but I'm making definite progress.
I will be using this forum as my "blog", so to speak, on the progression of the UltrascreenNEC project.
Stay tuned, there's more to come.