gbz80

 

This is my attempt at making an assembler for the Gameboy, in Rust. It takes an assembly file as input and outputs a binary that an emulator can run.

I made this mostly to learn and experiment with various things :)

Build

cargo build --release

Usage

gbz80 ./asm/shork/shork.gb.asm -o ./build/shork.gb
gbz80 ./asm/hello/hello.gb.asm -o ./build/hello.gb

-o [FILE] Set the output destination (required).
-D [SYMBOLS] Define symbols for conditional compilation.

Features

• A stripped down version of the syntax from the z80
• Constants
• Build-time expressions
• Macros
• Error reporting

An hello world example is available in asm/hello.

Reference

The instruction set is available here or in gen/instructions/opcode.html.
Some alternative mnemonics from the bottom of the page are used and replace all the other options, such that a plus or minus sign is never used within an instruction.

Structure of the project

• .vim: Syntax highlighting for '*.gb.asm' files in vim.
• asm: Examples and tests in assembly.
• gen: Code generation for the lexer.
  • gen/instructions: Generates the instructions list.
  • gen/lex: Generates syntax rules.
  • gen/image: Image conversion tool.
• sh Scripts and tools
• src Source code and tests for the assembler.

Build the docs with:

cargo doc --open

Or run in debug mode, it will show the result of every step in the process:

cargo r ./asm/shork/shork.gb.asm -o ./build/shork.gb
cargo r ./asm/hello/hello.gb.asm -o ./build/hello.gb

Sources

• Assembly tutorials:
  • https://www.chibiakumas.com
• Instruction set:
  • https://www.pastraiser.com/cpu/gameboy/gameboy_opcodes.html
• Cpu manual:
  • http://marc.rawer.de/Gameboy/Docs/GBCPUman.pdf
• BGB (emulator):
  • https://bgb.bircd.org/#downloads
• ROM analyzer:
  • https://www.romhacking.net/utilities/1343/
• Xxd (hex viewer):
  • https://linux.die.net/man/1/xxd
• Hello World:
  • https://www.chibiakumas.com/z80/helloworld.php
• Snake:
  • https://github.com/theisolinearchip/gb_raw_snake