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A disassembly of Super Mario Bros. 2.

This project is intended to fully disassemble, comment, and understandeverything about the gameSuper Mario Bros. 2 on the NES. In addition to thedisassembly, there is alsodocumentation about the game's formats,though those are more of a work in progress than the disassembly.

As an added bonus, a fully understood disassembly will also make modifying andchanging the game easier!

This is designed for use withasm6f.For your convenience, binaries of that have been included. (Windows/Linux)

Open a command prompt window and run:

build           (builds PRG0)build -dREV_A   (builds PRG1)build -dSM_USA  (builds Super Mario USA)

This will build the ROM from the assembly, and print any errors in the process.It will then output the SHA-256 hashes of PRG0 and PRG1, as well as the SHA-256hash of the assembled ROM, useful if you intend to keep a one-to-one build.

A version ofasm6f built under Ubuntu has been included undertools/.To build, run the following command:

./build.sh           (builds PRG0)./build.sh -dREV_A   (builds PRG1)./build.sh -dSM_USA  (builds Super Mario USA)./build.sh test      (builds both PRG0 and PRG1, verifying they match)

The build script will also display a message if the built ROM's SHA-256 hashmatches either PRG0 or PRG1.

The build process will generate a few files:

• bin/smb2.nes, your assembled ROM.
• bin/smb2.lst, the assembler listing. Use this to see how the code assembled.
• bin/assembler.txt, the log from the assembler
• bin/smb2.*.nl, name-listing files for FCEUX's debugger.
• Some other cruft, probably. welp

By default, the build script will create a byte-for-byte copy of the game,matching these two SHA-256 hashes:

• PRG0:47ba60fad332fdea5ae44b7979fe1ee78de1d316ee027fea2ad5fe3c0d86f25a
• PRG1:6ca47e9da206914730895e45fef4f7393e59772c1c80e9b9befc1a01d7ecf724

You can editconfig.asm to change some build options; see that file for details.

The "source" lives in thesrc directory:

• prg-x-x.asm are the program banks. They are grouped in pairs, as that is howSMB2 loads them. If you want to change this, you will need to split them apart again.
• defs.asm defines various enums and identifiers.
• ram.asm contains labels and definitions for RAM addresses.
• extras/ contains some additional fun things (seeconfig.asm).
• levels/ contains level and enemy data.
• music/ contains music and sound data.
• This list is growing as we split the disassembly into smaller parts.

• Fork the repository.
• Make changes.
• Submit a pull request!
• You are also encouraged to visit theDiscord serverif you have any questions.

• Data Crystal's SMB2 page
• CaptainSouthbird's SMB3 disassembly andDrakim's asm6f version
• Our Discord server