WIP: 16C firmware hack for more memory

[brouhaha]

My memory expansion microcode for the 16C is now working on the DM16L, with the microcode inserted into the SwissMicros DM16_32 firmware. I had to reduce the expanded RAM size slightly compared to what I've got in Nonpareil, because the SwissMicros ARM code implements hardware registers for the 15C's second R2D2 chip, whereas in Nonpareil I only do that for the 15C, and not other Voyager models.

After clearing the memory (WSIZE=16), f MEM reports "P-0 R-0773". If I set WSIZE=4, f MEM reports "P-0 R-3094". The microcode is patched to handle that many registers, and display four digits for the register count. It should now allow 999 step programs; I've tested that in Nonpareil, but not yet on the DM16L.

I was pleased to see that the SwissMicros serial console "s" command to dump memory actually works, so apparently that dumps all non-zero hardware registers from 0x00 through 0xff. Presumably the "l" command will support those as well, but I haven't yet tried it.

I've been thinking about expandnig the 15C and 16C memory even further, but that would probably NOT work with the SwissMicros firmware, because I doubt that SwissMicros supports RAM above 0xff. (To be fair, I haven't actually tried.). I'd have to write my own ARM code, which I've been considering doing anyhow, but if I did that I probably wouldn't support multiple fonts, the RTC, and other nifty features that SwissMicros provides.