https://github.com/mcejp/lux

Synthesizable Uxn CPU
https://github.com/mcejp/lux

fpga uxn

Last synced: about 1 month ago
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Synthesizable Uxn CPU

• Host: GitHub
• URL: https://github.com/mcejp/lux
• Owner: mcejp
• License: mit
• Created: 2022-06-22T20:09:26.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2022-07-14T17:33:04.000Z (over 2 years ago)
• Last Synced: 2023-03-09T23:32:13.519Z (almost 2 years ago)
• Topics: fpga, uxn
• Language: Python
• Homepage:
• Size: 274 KB
• Stars: 13
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
This is the repository of the Lux CPU project.

Currently it only implements one core, _Aurora-20_, which will serve as the basis of the LUX120A CPU. Documentation is TBD.

After cloning the repository, you can execute

    make test

to run some tests. You will need `unxasm` and Python 3.9ish in your PATH.

To recompile the ucode you will also need the `hy` package (precompiled ucode is provided for convenience).

![datasheet](_img/datasheet.png)

## Details

The core microarchitecture is implemented in `aurora_sim.py`.

It can be executed in two ways:

    ./aurora_sim.py            # Console output (#18 DEO) goes directly to stdout

    ./aurora_sim.py -hex       # output is printed in hexadecimal, handy for tests

No other I/O is implemented.

_aurora_sim_ assumes that `fw/fw.rom` had been built (it contains implementation of DIV/DIV2 instructions). Makefile will normally take care of this. Note that the address range 0xFF80~0xFFFF is taken up by these routines.

Not yet implemented:

- stack under/overflow traps

- _k_ & _r_ variants of DIV/DIV2

- error code on DIV/0 trap

Implemented only as high-level model:

- microcode sequencing

- multiplication

Unlikely to make it into Aurora:

- hardware division

- stack remapping to RAM

Note that I/O Devices are outside the scope of this project. An address/data bus will be exposed to attach them, though.

If you are interested in the microarchitectural details, you can also generate a readable listing of the entire microcode: `make ucode_au20.html`

![ucode](_img/ucode.png)