Simple CPU Emulator

A simple CPU emulator written in Rust.

This is mainly a learning project. The architecture is very simple and completely made up. Some inspiration came from the 6502 chip and the book "Compiler Design: Virtual Machines".

The code is fully documented. A list of instructions can be found here. Examples are in the examples/ folder.

Examples

Count from 10 to 1:

0x1fff:
    PUSHC
    !10
    # print the number
    PRINTN
    # subtract one
    PUSHC
    !1
    NEG
    ADD
    DUP
    # check if we are done
    JUMPZ
    !W0x200D
    # jump back to the print statement
    JUMP
    !W0x2001
    # halt
    HCF

More examples can be found in the examples/ folder. They can be run with cargo run --example <example name>.

Usage

The assembly instructions can either be specified directly in Rust or loaded from a file.

Parse assembly file

Parse an .asm file:

let mut mem = StdMem::from_file("examples/programs/add.asm").unwrap();
let mut cpu = Processor::new(ENTRYPOINT);

cpu.execute_until_hcf(&mut mem)?;

An example is located at examples/parse.rs.

Define instructions in Rust

Define instructions in Rust using the write_instructions macro:

let mut mem = StdMem::default();
let mut cpu = Processor::new(ENTRYPOINT);

use cpu::processor::Instruction::*;
write_instructions!(mem : ENTRYPOINT =>
    PUSHC,
    42,
    HCF
);

cpu.execute_until_hcf(&mut mem)?;

An example is located at examples/add.rs.