mre-mos6502/README.md

# mos6502

![](https://github.com/mre/mos6502/workflows/test/badge.svg)
[![docs.rs](https://docs.rs/mos6502/badge.svg)](https://docs.rs/mos6502)

An emulator for the [MOS 6502 CPU](https://en.wikipedia.org/wiki/MOS_Technology_6502) written in Rust.  
It builds on stable Rust and supports `#[no_std]` targets.

## Usage example

```rust
extern crate mos6502;
use mos6502::address::Address;
use mos6502::cpu;

fn main() {
    let zero_page_data = [56, 49];

    let program = [
        // (F)irst | (S)econd
        // .algo
        0xa5, 0x00,       // Load from F to A
        // .algo_
        0x38,             // Set carry flag
        0xe5, 0x01,       // Substract S from number in A (from F)
        0xf0, 0x07,       // Jump to .end if diff is zero
        0x30, 0x08,       // Jump to .swap if diff is negative
        0x85, 0x00,       // Load A to F
        0x4c, 0x12, 0x00, // Jump to .algo_
        // .end
        0xa5, 0x00,       // Load from S to A
        0xff,
        // .swap
        0xa6, 0x00,       // load F to X
        0xa4, 0x01,       // load S to Y
        0x86, 0x01,       // Store X to F
        0x84, 0x00,       // Store Y to S
        0x4c, 0x10, 0x00, // Jump to .algo
    ];

    let mut cpu = cpu::CPU::new();

    cpu.memory.set_bytes(Address(0x00), &zero_page_data);
    cpu.memory.set_bytes(Address(0x10), &program);
    cpu.registers.program_counter = Address(0x10);

    cpu.run();

    assert_eq!(7, cpu.registers.accumulator);
}
```

## Credits

This started off as a fork of [amw-zero/6502-rs](https://github.com/amw-zero/6502-rs),
which seems to be [unmaintained](https://github.com/amw-zero/6502-rs/pull/36) at this point.