Crate systemless 

High-Level Emulation (HLE) for classic Macintosh applications.

systemless runs Mac OS Toolbox apps without a real ROM by intercepting 68k A-line trap instructions ($A000–$AFFF) and dispatching them to native Rust handlers — the QuickDraw, Window Manager, Resource Manager, Sound Manager, SANE, and the rest of the Toolbox are reimplemented natively. The 68k CPU itself is interpreted by the m68k crate.

See the crate’s README.md for the architecture overview.

Quick start

use systemless::runner::{FixtureRunner, FixtureRunnerConfig};

// Allocate an 8 MiB guest, default config (kiosk mode — Mac menu
// bar suppressed; arrow keys not remapped to numpad).
let config = FixtureRunnerConfig::default();
let mut runner = FixtureRunner::new(8 * 1024 * 1024, config);

// Load a Mac executable (StuffIt archive, MacBinary, or raw
// resource fork — the loader auto-detects the format).
let bytes = std::fs::read("MyGame.sit").unwrap();
let _app = systemless::game::load_game(&mut runner, &bytes).unwrap();

// Step the guest until it halts or the budget runs out.
// The bool is `still_running` — false means the CPU halted.
let (steps_taken, still_running) = runner.run_steps(100_000, None);
println!("ran {} steps, still_running = {}", steps_taken, still_running);

Modules

audio

Host audio output backends.

cpu

CPU Backend - m68k wrapper

display

Shared framebuffer rendering for all Systemless frontends.

game

Shared game loading helpers.

loader

68k loader data types: CODE 0 header, jump table entries, and the LoadedApp state record returned by FixtureRunner::load_app.

machine_profile

Canonical guest machine profile used by Systemless’s accuracy harness.

managers

Toolbox managers

memory

Memory subsystem for Mac emulation

oracle

Cross-runtime parity oracle.

quickdraw

QuickDraw rendering primitives.

runner

Fixture Runner - Loading and execution infrastructure

sound

Sound Manager state and mixing engine.

trap

Trap Dispatcher - modular Mac OS trap handling.

Enums

Error

Top-level error returned by crate::runner::FixtureRunner and the supporting traps. Variants:

Type Aliases

Result

Result<T, Error> shorthand for any systemless operation.