Yet another VT-100 emulator

Finally back on the list!!! (yeah!) Comments to multiple messages follow: If you asked a question, please read through till you find it! I've got mainly ATI "Mach" and "3Drage" series cards in the older machines in my office, and while I can get some VESA modes to work, I haven't found any in the VESA range (100h-1FFh right?) that actually do 132 columns... I'm using INT 10h with AX=4F02h and BX containing the VESA SVGA mode number 100h-1FFh - is this right? I have found "vendor extensions" to the standard modes 00h-FFh which work fine at 132 columns on the ATI cards. Perhaps ... but one thing really appealing about going graphical is that I could properly support double-wide/double-high characters... I haven't figured out a way to do this in text mode ... I could do double-wide with some font manipulation, but there would be a line down the middle of the characters, and there isn't enough characters available even with two active character sets to do double-height/ double-wide. I'd also lose my current ability to emulate the VT-100 attributes. The big problem with a graphical version would be the "blinking" attribute - Do any graphics modes support blinking in hardware? - There's also the matter of incompatibilities in modes higher than 640x480 (which isn't enough for 132 columns). Nothing so disgusting. The problem is that you need to be able to do: Bold, Underline, Blinking and Reverse video in any and all combinations, and standard PC attributes can't do this - you can get close in mono VGA, but you still can't do all the combinations. For example, Underline only works in Mono, and not in combination with all other attributes. So what I did was to use VGA's capability of having two fonts (512 possible characters on screen at once), and generate a second font with underlines. Then the font select attribute bit becomes the underline bit. This conflicts with the standard "bold" attributes, however I reprogram the palette to provide increased intensity in another "color". This lets me do ALL the VT-100 attribute combinations without resorting to hardware dependancy (except that it needs a VGA adapter). For non-VGA cards, I just let you choose which attributes (or colors) will display for each of the 16 possible VT-100 attribute combinations. I also maintain two separate attribute tables for the TTY colors, one for when attribute emulation via VGA features is enabled, and one for not - so the attributes don't go completely wonky when you switch this feature on or off. It should work as long as your video supports standard 80 column color or mono video modes (Mode 3 or 7). If your video does not detect as VGA, you will be limited to the PC character set and attributes which are available. You can program the PC attributes that are displayed for each possible combination of VT-100 Bold, Underline, Blink and Reverse. If it does detect as VGA, but is incompatible with the features I used - you can disable the use of VGA fonts and attribute emulation in my configuration screens. You won't get my VT-100 character font, however I map the VT-100 characters which line up with PC characters into the appropriate character on the PC font. You will lose some of the VT-100 graphic character set. I map most of these into corresponding characters on the PC, however some don't have any PC equivalent, and I map these into PC characters 80-89 (which I replace in my VT-100 font). At the moment, my mapping of VT-100 characters (standard and graphical) to the PC character set is fixed (you can change the charcters displayed by loading a different character-set under VGA) - but if there is a requirement, I could make the mapping tables configurable - This would let you pick any PC character to display for any particular VT-100 character. What I've done is to enable you to configure the 132 column mode under "General Parameters" - Standard modes 01h-FFh should work, as well as VESA SVGA modes 100h-1FFh. If a mode is configured, then I enable the "132 column mode" under "General switches" as well as the DEC private {ESC}[?3h/l mode set/reset. I've also provided FIND132 which helps locate a 132 column video mode for your adapter. I'm still researching VESA - as Jim said, perhaps I can directly determine a suitable mode from the information returned by the VESA BIOS. In my case, I do want it to work with BIOS calls - I tend to use it on DOS machines in my workshop, and I don't want to make it dependant on anyone's particular hardware. If you are using windows, I'm sure there are better VT-100 emulators since you should be able to do the double-sized modes easily in a graphical environment. But so far it still works fine on my Win2K machine (Haven't tried it on XP lately, but I will). If there are any more suggestions or feedback, please keep it coming. Probably this weekend, I'm going to rename the package (*) and get it moved into a permanent home under "Simulators and Emulators" on my site (with an extra link in the terminals/VT-100 section). (*) LAPTALK made sense when it was a tiny telecom program for my floppy based laptop, but it's much more a VT-100 emulator now). I'm thinking something simple like "PC100", but suggestions are welcome. Dave -- dave06a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.classiccmp.org/dunfield/index.html