david-given
Joined 13 years ago
Joined 13 years ago
I have, BTW, just received a $6.50 watch with touchscreen, microphone and speaker, much better build quality, BT 3, 4.2 and 5, plus the traditional fake heart rate sensor and a bigger battery with an actual label on it. It's powered by a YC1133 which contains an ARM Cortex M0 with 56kB RAM and 4MB flash. This would be an awesome device for hacking if there was any information about it whatsoever.
Weirdly, it runs a more complex version of what's clearly the same software stack as the LT716!
On the Master I could fairly easily extend the TPA up into the sideways RAM area, adding another 16kB, for a total of probably about 45kB. The difficulty is that filesystems in Acorn's MOS can't access sideways RAM directly, as that's where the filesystem module itself lives, so all I/O would have to be done by copying the data to low memory, calling MOS, then switching the sideways RAM back in again afterwards. There may also be subtleties in catching interrupts and things which might try to change sideways RAM pages. But it should totally work.
For the _really_ advanced version, it could run bare metal and reuse the OS workspace at 0xc000 all the way up to 0xe000. But that would lost all MOS services, so would have to reimplement things like screen redrawing and floppy disk handling.
Responding to a few random things posted here:
- yes, that 8080 emulator ought to work fine. Not sure what the performance would be like but it's certainly worth a try. Sadly, unless the author shows up and relicenses it I can't use that one ('may not be redistributed without express written permission of the author').
- llvm-mos: the only bits in C are some of the utilities, and that's only because I happened to have (buggy) C versions from one of my other CP/M projects. What I'd actually like to do is to write a PL/M compiler with LLVM and try and compile the original Digital Research code for the 8080 with it.
- re porting: should be trivial to do! The only thing you need is a BIOS, with console I/O and sector read/write. Everything else is the same. You can even use the same binaries. But the documentation is trivial, so if you're interested file a github issue and I'll try to assist.
Also, I _really_ want some software for this thing, primarily programming languages. I do plan to port Microsoft's BASIC (now open source), but I need an assembler. If anyone knows any suitable 6502 assemblers from back in the day _which have actual licenses_ please let me know.