Home Page Forums MAME MAME PC/XT/AT (inside) WIP topic

https://www.jammarcade.net/wiki/index.php?title=Olivetti_Prodest_PC1-DFD_(Double_FDD_version)

They have JEDEC files for the GALs on the double FD version.

According to that, the mouse is a custom thing that would require specific emulation. The part that handles writes to usual pc hardware also isn't working so most pc software won't work. I think I have an idea of what happens but the details aren't clear.

Gimme a sec to sort through what I just received from Simone, pull request coming in as well

Right, so it looks as if the BIOS we had (1.21) was from a PC1 HD, there are now two more revisions from "plain" PC1's.

Simone says "In effect, the PC1 BIOS is different, [...]Not much difference but they lack HD support, obviously."

The new added BIOS versions (1.06 and 1.07) contain the string "Fixed Disk", though.

Next, Simone wrote "The 8042 keyboard controller is protected and it was programmed to take into account of Joystick movments (translated to keycodes) and mouse Keys. I'll bet that the Olivetti M24 (or AT&T 6300) keyboard controller is quite the same chipset, so you can try it if you can find something.
The mouse X/Y coordinates are directly supported from the YAMAHA video chip (yes!). I wrote a specific mouse driver (in assembler) for it that take advantage of this chip and his mouse (much smaller and faster of the originar mouse driver)"

I've uploaded his driver and asked him to share his source code, so I hope this is forthcoming.

The video chip supports a graphical mouse cursor over text mode, as seen here: https://www.youtube.com/watch?v=-8K...ZY2p9HIxVd99oXEqkDePhvUSTcnoKtpKNmpNVd4Y

Thanks to both crazyc and Simone2013!!!

The M24 originally used a 8041A as its keyboard interface, but later replaced it with a TMS7000. I believe only the latter has been dumped (and emulated).

The ROM that went with the TMS7000 probably came from my machine. I have two more sets of ROMs which I've (re-)uploaded, they seem to contain a dump of a M24's 8041 keyboard ROM.

I've uploaded an archive with ROMs and pictures of the Diamond SpeedStar 24 (ET4000AX) graphics card and the Seagate ST02 8bit ISA SCSI controller with integrated floppy controller.
The ST02 is interesting as it allows to use HD drives to be used on an XT class machine if your system BIOS supports it.

I've divided at.cpp up into at.cpp, at386sx.cpp, at386.cpp, at486.cpp and amstr_megapc.cpp. The source file was already getting a bit unwieldy, but additional dumps are still coming in.

Before I create a pull request, I'd like to ask MAME Dev to check my repository at https://github.com/rfka01/mame/commits/master if this is the preferred direction for this driver. I've asked Micko as one of the creators of the file, and he's fine with the split, but referred to a recent conversation on Discord discussing the future of the PC drivers.

Alternatives would be splitting the file along other lines (chipset, manufacturer) or just adding to the existing at.cpp - I'm open for opinions and guide lines.

The original IBM PC AT (5170) BIOS has a race condition that results in a read timeout on "too fast" hard disks. This includes the emulated disk of MAME, and consequently an emulated 5170 can not read properly from its virtual disk.
Details of the race condition can be found at https://archive.org/details/ibm-5170-type-3-bios-cover

Is there a way to slow down the emulated disk? The emulated floppy seems to run at about the same speed as a real one, but the hard disk apparently not.

AFAIK the tms7000 ROM came from an AT&T PC6300 I have here, although it may be identical to the one in your machine.