1518ffbc60
Previously it was storing data in the registers, which was an array of u8, but now it's storing eg. full addresses for the scroll tables so that they don't need to be fetched from the register values and converted every rendering. I was thinking this would maybe make DMA debugging easier, in particular. |
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todo.txt |
Moa
Started September 26, 2021
Moa is an emulator/simulator for computers using various 68000 and Z80 CPUs and peripherals. The original idea was to emulate the computer I had built as part of the Computie project.
Currently it can simulate Computie (68000) and the TRS-80 Model I (Z80), and I'm working on supporting the Macintosh 512k and Sega Genesis.
For more detail, check out this post about how I started the project: Making a 68000 Emulator in Rust
Running
For Computie, it can do everything the 68k-SMT board can do, including run the monitor program and load the Computie OS kernel and boot it from the CompactFlash card. To run it:
cargo run -p moa-console --bin moa-computie
It will open two PTYs: one for the serial terminal, and one for the SLIP
connection. Once open, it will try to launch both pyserial-miniterm
as a
separate process and connect to the Computie PTY. It will also launch
slattach
with the associated setup commands to create the SLIP device on the
host, and set up host routing. The exact commands in
src/machines/computie.rs
might need to be adjusted to work on different
hosts.
For the TRS-80, it can run Level I or Level II Basic, but it doesn't yet
support a cassette tape drive or floppy drive. I haven't tested it that
thoroughly either, so any help with it would be welcome. I mostly made it to
test the Z80 cpu implementation in a simpler computer before I used in the
Genesis emulator. The frontend uses the
minifb
rust crate to open a window
and render the characters to screen, as well as accept input from the keyboard.
cargo run -p moa-minifb --release --bin moa-trs-80 --
By default it will start Level I Basic. To use the other rom, add the option
--rom binaries/trs80/level2.rom
The Genesis emulator is a work in progress but can be run with:
cargo run -p moa-minifb --release --bin moa-genesis
By default, the minifb frontend will scale the window by 2. This can be
changed with the --scale [1,2,4]
option.
The -d
or --debugger
option will make the emulator start the debugger
before running. There is a simple built-in debugger for stepping through
the rom instructions being emulated. The state of the CPU registers will
be displayed after each instruction, breakpoints can be set, memory contents
can be examined, and memory locations can be modified. This has helped a lot
with tracking down errors in the emulator itself.