Mega Man 4 (NES) Disassembly

About

Mega Man 4 is a 1991 platform game developed and published by Capcom for the Nintendo Entertainment System, released in Japan in December 1991 and later in North America and Europe. This is a complete disassembly of the NTSC-U Mega Man 4 (NES) ROM, covering all code and data, and reassembles to a byte-for-byte clean ROM using the included xkas-plus build (a prebuilt Windows binary is bundled for convenience). The game uses the MMC3 mapper chip with 64 PRG banks of $2000 bytes each; not all of the disassembled code is documented yet.

Getting started

Assemble the disassembly with `./xkas -o mm4.nes assemble.asm` to produce a clean ROM identical to the original, which can then be run in any NES emulator.

Credits & contributing

• The disassembly itself is complete, but documentation of the code isn't finished — the author welcomes pull requests to add it.