Emulated Woz Machine

Introduction

Two years ago between christmas and new year I wrote a tiny and incomplete 6502 emulator and turned it into an original Apple 1 emulator. It was a fun and nostalgic project to work on. I grew up with the Apple II and never had a change to see an Apple 1 in action.

A few weeks ago I decided to pick this project up again. I am extremely motivated to turn this into a high quality emulator that supports the Apple 1, Replica 1, Apple ][+ and Apple IIe. Some of that work is really close to being finished, other work will take many months of spare time hacking.

Goals & Status

Here are some of the things I want to accomplish for each emulated machine:

CPU Emulator

• 6502 support
• 65C02 support
• Tracing facility
• Debugger
• Speed throttling

Apple 1

8K / 6502 / Classic ROM

• Terminal based emulation
• Classic display emulation (SDL based)
• Cassette interface

Replica 1

32K / 65C02 / KRUSADER ROM

• Terminal based emulation
• Classic display emulation (SDL based)
• Cassette interface
• CFFA1 Support

Apple ][+

48K / 6502

• Basic Apple ][+ architecture implementation - In progress
• Disk II emulation - In progress
• Display Emulation - 40 Column mode
• Display Emulation - Low resolution graphics
• Apple Language Card
• Joystick Support
• Audio Support
• Display Emulation - High resolution graphics - Mostly works.

Building the emulator

EWM is written in Rust (ported from the original C implementation; see REWRITE.md for the full story). You need a Rust toolchain (rustup) and SDL2 (brew install sdl2 / apt install libsdl2-dev).

cargo build --release

Running the emulator

cargo run --release -- two --color --drive1 disks/DOS33-SamplePrograms.dsk

Running cargo run --release with no arguments opens the bootloader menu, where keys 1/2/3 pick the machine. See --help on each subcommand (one, two) for all options.

cargo test runs the full verification suite: the Klaus Dormann 6502/65C02 functional tests, golden instruction traces captured from the C emulator, headless machine boot tests, a full DOS 3.3 boot with CATALOG, and a golden screenshot comparison. There are also headless consoles for quick experiments without a window:

cargo run -p ewm-core --example one                                  # Woz monitor
cargo run -p ewm-core --example two -- disks/DOS33-SystemMaster.dsk  # AppleSoft/DOS

The cc65 assembly sources under tests/ are manual test programs for the machines themselves and are not part of the automated suite.