8-bit-CPU VS customasm

I later built a version that can read/store a full byte (2 key-presses) and present it to a CPU.

My code is available here, it has evolved since then and I actually abandoned the in-Arduino emulator later (re-wrote that part in Verilog). So it is best viewed at historical tag "emulator_1.0" in the repository.

Mark your data using PROGMEM directive (see example).

My project sources are on GitHub. Theres a lot going on, and it is probably a bit over-engineered. You can start by taking a look at Arduino sketch and client library.

I wrote an emulator for mine, then extended it to test out different designs, before building on hardware. The approach was a bit different, as I started by implementing 74-series logic chips. Then "wired" them together into CPU modules. This way emulator becomes a testable representation of what's possible using logic chips.

I wrote an emulator for my CPU in Verilog. Actually, I made it to test out various aspects before building, real hardware has not yet cached up with it.

The source code was in Python. I was able to debug it using Arduino-based adapter and (by using some "magic") translate into machine code binary. Since then I've switched to CustomAsm for code compilation and have other means to debug (emulator and debugger tool).

If you looking for examples: here's how you create the array (code generated using xxd -i command), and here's how you use the array.

In the beginning of program (on EEPROM), there's a small piece of code that reads all 256 address locations and writes them back. In BOOT mode, this effectively copies contents from ROM into RAM.

Complicated? Perhaps, but do not underestimate the power of automated testing! When you can run a couple dozen tests in just few seconds, at any time, it really gives you confidence about the system. Obviously, one should spend time writing the tests, but it pays back rather quickly.

I'm using customasm to write code in Turing Complete.

also if you start writing programs for your own CPUs, use something like CustomASM so you don't have to write in machine code.

either way if you plan on doing more CPUs and similar in the future i highly recommend CustomASM.

The source code was in Python. I was able to debug it using Arduino-based adapter and (by using some "magic") translate into machine code binary. Since then I've switched to CustomAsm for code compilation and have other means to debug (emulator and debugger tool).

Even though technically not an emulators-related post, I'd like to share a tool I've recently learned came across and found to be really useful. It's called customasm and is open source. It can compile assembly of any kind as long as you feed it with (what's called) rules-definition. You can even write a higher level language profile (such as C, sort of) through it, the possibilities are countless, so to say.

I've got the documentation in the wiki! https://github.com/hlorenzi/customasm/wiki/User-Guide

Thanks to hlorenzi, making an assembler is a bunch of work. https://github.com/hlorenzi/customasm

anyways, it might be a good idea to throw the entire project on Github once it's done. stuff like schematics, BOM, details about the function of the CPU, maybe an Assembler (CustomASM is pretty good), also maybe a simulator version in something like Digital or Logisim so that people can look at it, write programs, or rebuild it with different parts and such

I used https://github.com/hlorenzi/customasm along with info from https://www.reddit.com/r/beneater/comments/cori8t/custom_asm_compiler_definition/