README.md

gameboy-decoder

how it works

given a rom.gb file, romdecoder prints out all the information included in the rom header, and produces a rom.asm file containing the bytes from addr 0x0150 to EOF reverse-parsed (disassembled) into Z80 ASM instructions.

src files

• romdecoder.cpp
  the main source file, it decodes the rom header and calls the bytes to Z80-ASM instructions decoder.
• licensecodes.h
  contains the functions to translate bytes into rom license codes.
• z80asm.h
  contains all the functions to parse bytes into Z80-ASM instructions.

environment

compiled and tested with Microsoft cl version 19.34.31937 for x64

soruces and docs used

gameboy rom header format:

• https://www.devrs.com/gb/files/gbspec.txt
• https://gbdev.gg8.se/wiki/articles/The_Cartridge_Header

gameboy Z80 ASM instruction set (and decoding algorithm):

• https://imrannazar.com/Gameboy-Z80-Opcode-Map
• https://gb-archive.github.io/salvage/decoding_gbz80_opcodes/Decoding%20Gamboy%20Z80%20Opcodes.html

Z80 ASM documentation:

• https://www.zilog.com/docs/z80/um0080.pdf