[cctalk] Re: vt220 firmware source?
On Mon, 5 Feb 2024 19:16:46 - "Rob Jarratt" wrote: > Your annotated VT100 listing was invaluable in helping me to fix my > own VT100 (still not working though, but on the video output side). > Would be interested in how you did it, I get the impression from your > message that you used an emulator to observe the behaviour? The main write-up on that is here: https://vt100.net/dec/vt100/rom/how (which I am always prepared to revise, if something doesn't make sense!) I started with MAME, because it supports VT100 emulation with the exception of smooth scrolling, and because it has a really excellent debugger. However, I had to switch to my own program based on Nicolas Allemand's 8080 core in the end, for two reasons: 1. I needed to stimulate the terminal with serial inputs and key presses and observe the serial outputs, and 2. I needed to know that I had covered the entire ROM, so I combined the 8080 core with a coverage checker, to mark all reads, writes and DMA accesses to RAM while it worked its way through a file that contained stimulation instructions: "pause", "keyboard character", "serial input", etc. Coverage checking might sound bizarre, but I had some code that I disassembled, understood and documented and could not for the life of me work out why I couldn't provoke it into executing; it turned out to be a bug in the firmware. Regards, Paul
[cctalk] Re: vt220 firmware source?
you may already know about these but here are a few 8051 Simulators: https://www.electronicshub.org/8051-simulators/ And thoughts on using MAME to emulate terminals: https://zork.net/~st/jottings/Real-VT102-emulation-with-MAME.html Good luck. I have a fully functional VT-330+ and a fully functional VT-220 if i can help at all. On 2/5/2024 10:23 AM, Paul Flo Williams via cctalk wrote: On Sun, 04 Feb 2024 16:26:57 -0700 Richard via cctalk wrote: In article you write: I'm about to dive in to commenting the disassembly listings, but figured I'd ping here to see if anybody might have done this already in case I wouldn't have to start from scratch? Give IDA Pro or Ghidra a crack at it to help you make sense of the raw disassembly. I made pretty good progress on VT100 ROMs before Paul Williams put up a completely reverse engineered commented listing. Well, in case it helps, I'll explicitly disclaim any intention of disassembling the VT220 :-) After the VT100, I did make a start on the VT102/131 combination but it seemed too samey to hold my interest. More than 20 years ago, I started on the VT320, as my personal favourite, but I didn't understand how to tackle emulation at the time, the 8051 emulator I wrote had flaws, and I spent a long time on getting the emulated video timing correct enough to even pass self test! If only the VT320 had had a technical reference as comprehensive as that published for the VT100. I will return to it at some point, probably using some else's 8051 core, as Peter Sichel (last head of DEC's terminals group) bet me that I wouldn't be able to do it. At the moment, I'm tackling another full commentary, but it may well have an even smaller audience than that for the VT100; I'm 83% through gutting the arcade game Star Force. I've even fixed two æsthetic bugs in the game, 40 years too late for anyone to care. At least this is Z80 assembler, and tinkering with that has always made me *very* happy. Paul.
[cctalk] Re: vt220 firmware source?
> -Original Message- > From: Paul Flo Williams via cctalk > Sent: 05 February 2024 16:24 > To: cctalk@classiccmp.org > Cc: Paul Flo Williams > Subject: [cctalk] Re: vt220 firmware source? > > On Sun, 04 Feb 2024 16:26:57 -0700 > Richard via cctalk wrote: > > > In article you > > write: > > >I'm about to dive in to commenting the disassembly listings, but > > >figured I'd ping here to see if anybody might have done this already > > >in case I wouldn't have to start from scratch? > > > > Give IDA Pro or Ghidra a crack at it to help you make sense of the raw > > disassembly. > > > > I made pretty good progress on VT100 ROMs before Paul Williams put up > > a completely reverse engineered commented listing. > > Well, in case it helps, I'll explicitly disclaim any intention of > disassembling the > VT220 :-) > > After the VT100, I did make a start on the VT102/131 combination but it > seemed too samey to hold my interest. Hello Paul, Your annotated VT100 listing was invaluable in helping me to fix my own VT100 (still not working though, but on the video output side). Would be interested in how you did it, I get the impression from your message that you used an emulator to observe the behaviour? Thank you so much! Rob > > More than 20 years ago, I started on the VT320, as my personal favourite, but > I didn't understand how to tackle emulation at the time, the 8051 emulator I > wrote had flaws, and I spent a long time on getting the emulated video timing > correct enough to even pass self test! If only the VT320 had had a technical > reference as comprehensive as that published for the VT100. I will return to > it > at some point, probably using some else's 8051 core, as Peter Sichel (last > head > of DEC's terminals group) bet me that I wouldn't be able to do it. > > At the moment, I'm tackling another full commentary, but it may well have an > even smaller audience than that for the VT100; I'm 83% through gutting the > arcade game Star Force. I've even fixed two æsthetic bugs in the game, 40 > years too late for anyone to care. At least this is Z80 assembler, and > tinkering > with that has always made me *very* happy. > > Paul.
[cctalk] Re: vt220 firmware source?
On Sun, 04 Feb 2024 16:26:57 -0700 Richard via cctalk wrote: > In article you > write: > >I'm about to dive in to commenting the disassembly listings, but > >figured I'd ping here to see if anybody might have done this already > >in case I wouldn't have to start from scratch? > > Give IDA Pro or Ghidra a crack at it to help you make sense of the raw > disassembly. > > I made pretty good progress on VT100 ROMs before Paul Williams put up > a completely reverse engineered commented listing. Well, in case it helps, I'll explicitly disclaim any intention of disassembling the VT220 :-) After the VT100, I did make a start on the VT102/131 combination but it seemed too samey to hold my interest. More than 20 years ago, I started on the VT320, as my personal favourite, but I didn't understand how to tackle emulation at the time, the 8051 emulator I wrote had flaws, and I spent a long time on getting the emulated video timing correct enough to even pass self test! If only the VT320 had had a technical reference as comprehensive as that published for the VT100. I will return to it at some point, probably using some else's 8051 core, as Peter Sichel (last head of DEC's terminals group) bet me that I wouldn't be able to do it. At the moment, I'm tackling another full commentary, but it may well have an even smaller audience than that for the VT100; I'm 83% through gutting the arcade game Star Force. I've even fixed two æsthetic bugs in the game, 40 years too late for anyone to care. At least this is Z80 assembler, and tinkering with that has always made me *very* happy. Paul.
[cctalk] Re: VCF SoCal
On Fri, 2 Feb 2024 at 21:01, Marvin Johnston via cctalk wrote: > > Note to those people too lazy to update their subject line... Oh come on, you can't say that and not quote properly. For just me, I intentionally don't do it. For better or worse, Gmail is the best webmail I know if, it does plain text and bottom posting, and it works across my 5 ot 6 laptops, 3 phones and a desktop perfectly. But it hates subject line changes and it destroys its threading. So I never, ever do it if I can avoid it. It is not laziness, like bad quoting. It's 100% intentional. As for info... Didn't you just try Google? vcf south california 1st hit: https://www.vcfsocal.com/ -- Liam Proven ~ Profile: https://about.me/liamproven Email: lpro...@cix.co.uk ~ gMail/gTalk/FB: lpro...@gmail.com Twitter/LinkedIn: lproven ~ Skype: liamproven IoM: (+44) 7624 277612: UK: (+44) 7939-087884 Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053
