mirror of
https://github.com/mre/mos6502.git
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129 lines
3.2 KiB
Markdown
129 lines
3.2 KiB
Markdown
# mos6502
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[](https://travis-ci.org/mre/mos6502)
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An emulator for the MOS 6502 CPU written in Rust.
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## Features
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* Builds on stable Rust.
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* Runs on [`#[no_std]`](https://doc.rust-lang.org/1.7.0/book/no-stdlib.html), which means it works without the standard library. It is
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portable, has very few dependencies, and doesn't depend on a full-fledged
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`libc`.
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## Usage example
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```rust
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#![no_std]
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extern crate mos6502;
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use mos6502::cpu;
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use mos6502::address::Address;
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fn main() {
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let mut cpu = cpu::CPU::new();
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let zero_page_data = [
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// ZeroPage data start
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0x00,
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0x02, // ADC ZeroPage target
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0x00,
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0x04, // ADC ZeroPageX target
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0x00,
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0x00,
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0x00,
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0x00,
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0x10, // ADC IndexedIndirectX address
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0x80, // ADC IndexedIndirectX address
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0x00,
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0x00,
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0x00,
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0x00,
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0x00,
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0x08, // ADC IndirectIndexedY address
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0x80, // ADC IndirectIndexedY address
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];
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let program = [
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// Code start
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0xA9, // LDA Immediate
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0x01, // Immediate operand
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0x69, // ADC Immediate
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0x07, // Immediate operand
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0x65, // ADC ZeroPage
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0x01, // ZeroPage operand
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0xA2, // LDX Immediate
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0x01, // Immediate operand
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0x75, // ADC ZeroPageX
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0x02, // ZeroPageX operand
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0x6D, // ADC Absolute
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0x01, // Absolute operand
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0x80, // Absolute operand
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0xA2, // LDX immediate
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0x08, // Immediate operand
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0x7D, // ADC AbsoluteX
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0x00, // AbsoluteX operand
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0x80, // AbsoluteX operand
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0xA0, // LDY immediate
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0x04, // Immediate operand
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0x79, // ADC AbsoluteY
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0x00, // AbsoluteY operand
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0x80, // AbsoluteY operand
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0xA2, // LDX immediate
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0x05, // Immediate operand
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0x61, // ADC IndexedIndirectX
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0x03, // IndexedIndirectX operand
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0xA0, // LDY immediate
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0x10, // Immediate operand
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0x71, // ADC IndirectIndexedY
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0x0F, // IndirectIndexedY operand
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0xEA, // NOP :)
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0xFF, // Something invalid -- the end!
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];
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let data: [u8; 25] = [
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0x00,
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0x09, // ADC Absolute target
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0x00,
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0x00,
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0x40, // ADC AbsoluteY target
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0x00,
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0x00,
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0x00,
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0x11, // ADC AbsoluteX target
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0x00,
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0x00,
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0x00,
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0x00,
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0x00,
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0x00,
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0x00,
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0x12, // ADC IndexedIndirectX target
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0x00,
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0x00,
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0x00,
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0x00,
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0x00,
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0x00,
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0x00,
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0x06, // ADC IndirectIndexedY target
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];
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// "Load" a program
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cpu.memory.set_bytes(Address(0x0000), &zero_page_data);
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cpu.memory.set_bytes(Address(0x4000), &program);
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cpu.memory.set_bytes(Address(0x8000), &data);
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cpu.registers.program_counter = Address(0x4000);
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cpu.run();
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}
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```
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## Credits
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This started off as a fork of [6502-rs](https://github.com/amw-zero/6502-rs),
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which seems to be unmaintained at this point.
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