Summary

This pull request adds initial emulation of the Mazovia 1016, which was a homegrown IBM PC/XT clone designed in Poland using components available in the Eastern Bloc. Notably, as 8088 clone CPUs were not available at this time, the Mazovia adapts the XT design to use an 8086 CPU, albeit with I/O bus accesses lengthened by an additional cycle (as documented by the references).

Note that this attempts to emulate the original "M86" design. Some manufacturers of the Mazovia later switched to using the same cases to fit (cheaper) Taiwanese 8088 XT boards under their own brand - for example, there exists a BIOS dump from 1989 which is the Phoenix XT 2.27 BIOS with stripped out and replaced copyright notices (no, really, that's the only major difference). I'm not sure if there's a point in emulating that.

Unfortunately, as I do not have access to a functional unit, some aspects (in particular, if the keyboard emits any non-standard scancodes) could not be documented; thus why I consider this emulation "initial", but sufficient.

Checklist

• Closes #xxx
• I have discussed this with core contributors already
• This pull request requires changes to the ROM set
  • I have opened a roms pull request - Add Mazovia 1016 ROMs roms#281

References

• Popko, Janusz. 1988. Jednostka centralna Mazovii 1016. Informatyka 1/1988, pages 9-10 (system architecture overview)