MiSTer FPGA Forum

Hi

Can it be possible to support amstrad pc 1512 bios ?

Thanks in advance

breiztiger wrote: ↑Fri Nov 11, 2022 7:53 pm Hi

Can it be possible to support amstrad pc 1512 bios ?

Thanks in advance

Hi! Have you tried to load the bios? I'm curious

As special I read it has 640x200 x 16 color CGA

This was my first PC, i'd love to run it again on MiSTer

Oh man, my first computer was also an Amstrad XT clone (though a bit later, I had a 3086). I was just looking through some Amstrad info the other day in nostalgia mode: https://www.seasip.info/AmstradXT/bios.html

Never really understood all the XT / IBM compatible stuff back in the day

Adapting the core to the different particularities of each machine is no easy task.

The closest we have now is PCjr, only because of the different way of handling the keyboard. At least in the medium and short term, I don't strive to more.

Options are very difficult on FPGA, because the core has to carry all the hardware for all the options, including all the traces, even when they're not being used. Stretching the XT core to cover Tandy and PCjr is obviously possible, but those were the most widely used 8088 machines. There's quite a bit of unique software for each, so the effort seems worthwhile.

I didn't grow up in Europe, so I'm not familiar with that market, but I don't think there's much software that takes advantage of the unique Amstrad features, so the extra work involved in doing FPGA emulation likely isn't very attractive. If you want specific PC clones, you're better off looking at software emulators like PCEM or 86Box. It's (relatively) easy to be flexible in software emulation, and they cover lots of clones with high accuracy. Adding the Amstrad 1512 to their infrastructure is just a special case, where every new model in the same FPGA core becomes exponentially more complex.

It's likely possible to make a new core for just the Amstrad, but unless there's some really compelling software on that system that I haven't heard about, that's a fair amount of work and additional project maintenance burden for a very slim benefit.

Yes, there aren't many games that make use of the 16 colour CGA mode as Amstrad soon went to EGA with the PC1640, and for the few games that do support it, they mostly also support EGA anyway. There's only a handful of games where it's the best possible graphics mode - some good info here:

https://www.vogons.org/viewtopic.php?t=86918

As an aside, Sierra was one of the developers who did support it for a couple of games, the driver they created for this has since been modified by vogon users so that it can be used in all sierra SCI engine games (though again, it's never the best option):

https://www.vogons.org/viewtopic.php?p=983284#p983284

PC1512 support would be lovely to have at some point as with all the Amstrad variants (selfishly I'd like to see the 3086 as that's my childhood), but that's more for nostalgia and preservation then any specific compelling use case that I can think of. All the games I played back then no doubt work the same or better on other XT hardware.