A full Intel 8080 CPU emulator in Rust.

This crate is now a no_std CPU core. It focuses on Intel 8080 execution only; file loading, threading, timers, host messaging and platform-specific I/O are expected to live outside the crate.

To verify the emulation, run below:

cargo run --features="cpu_diag", making sure CPU IS OPERATIONAL gets popped up.

This library is intended to be portable on different platforms: macOS, iOS, Android and (if possible) Web.

Feature flags:

• cpu_diag: enables the bundled diagnosis flow and its debug output.

How to use

Create a CPU with ROM bytes and RAM, then drive it from your host loop.

Usage

1. Construct Cpu8080 with Cpu8080::new(rom, ram), where rom: &[u8] and ram: &mut [u8] are owned by the caller.
2. If you need a different address-space layout, implement the Memory trait and build the CPU with Cpu8080::with_memory(...).
3. Call step() to execute one instruction, or run() to keep executing until the CPU halts or needs host-visible I/O.
4. When you receive ExecutionState::Input { port }, fetch the value from your platform and pass it back with provide_input(value).
5. When you receive ExecutionState::Output { port, value }, forward it to your platform-specific device model.
6. Use interrupt() and restart() from your host when the platform needs to inject interrupts or reset the CPU.
7. Use get_ram() with the default SplitMemory layout, or memory() / memory_mut() if you are using a custom memory implementation.

Example

use i8080emulator::{Cpu8080, ExecutionState};

let mut ram = [0; 0x4000];
let mut cpu = Cpu8080::new(rom, &mut ram);

loop {
    match cpu.run()?.state {
        ExecutionState::Continue => {}
        ExecutionState::Input { port } => {
            let value = platform_read(port);
            cpu.provide_input(value)?;
        }
        ExecutionState::Output { port, value } => {
            platform_write(port, value);
        }
        ExecutionState::Halted => break,
    }
}

Apps powered by this library

• Space Invaders on macOS + iOS

Swift / C FFI

The repo now also contains a thin FFI crate for Swift and other C-compatible hosts.

• Build it with cargo build -p i8080emulator-ffi --release
• The exported header is at ffi/include/i8080emulator_ffi.h
• The static library will be emitted under target/release/

The FFI layer is now also no_std/no-allocation. The host owns CPU storage, ROM, and RAM:

• i8080_cpu_size / i8080_cpu_align
• i8080_init_cpu / i8080_deinit_cpu
• i8080_run / i8080_step
• i8080_provide_input
• i8080_interrupt
• i8080_restart
• i8080_ram_ptr / i8080_ram_len