NBA Jam Recompiled

NBA JAM Recomp

Castellano: README.es.md

Midway's NBA JAM arcade saga, rebuilt from its original source code and played in one Windows application with a game picker, CRT shaders, widescreen modes and online play.

Created by Pocket_lucho with Claude (Anthropic). If you want to support me, go to https://buymeacoffee.com/pocket_lucho

Game	Board	Status
NBA JAM (1993), rev 3.01	T-Unit	runs from the MAME romset (its source code was never published)
NBA JAM Tournament Edition, rev 4.0	T-Unit	built from source: program and graphics byte-identical to the original ROM
NBA JAM T.E. Special Edition, rev 5.02 (Asure, 2025)	T-Unit	built from source: program byte-identical
NBA Hangtime, L1.3 / L1.1	Wolf Unit	runs from the ROMs
NBA Maximum Hangtime, 1.3	Wolf Unit	built from source: program byte-identical (1.03 from MAME also runs)

Download

• Windows 10/11 x64: releases/NBAJamRecomp-windows-x64.zip
• Linux x64 (glibc 2.38+): releases/NBAJamRecomp-linux-x64.tar.gz

Unpack, copy your ROMs into roms/ (see below) and run NBAJamRecomp.

No game data is included

Midway's code, graphics, sound and music are copyrighted, so neither this repository nor the releases contain any of them. Each user copies their own files into roms/:

• MAME romsets: nbajam.zip, nbajamte.zip, nbahangt.zip, nbamht.zip
• and/or the ZIPs of the public source repositories ("Code → Download ZIP"): historicalsource/nba-jam-tournament-edition, Asure/nba-jam-tournament-edition-SE, historicalsource/nba-hangtime

The application scans roms/ (sub-folders and ZIPs included), recognises every file by CRC32 and extracts what each game needs when it starts. See dist/NBAJamRecomp/README.txt for the per-game list. Games built from source with tools/build_roms.sh (below) go to data/<game>/ and are used when the ROMs are not found.

Features

• Game picker ordered by release date, Spanish / English interface
• OpenGL 2.1 / GLES 2 shaders: sharp, smooth, scanlines, CRT, curved CRT; integer (pixel perfect) scaling; 4:3, 16:9, 16:10 or fill
• Online play for up to 4 players: lockstep over UDP, with ROM fingerprint and desync detection
• Keyboard (4 players) and gamepads, per-game NVRAM, screenshots (F12)

Repository layout

Path	Contents
src/emu	minimal MAME-compatible device framework
src/mame	unmodified MAME CPU cores (TMS34010, M6809, ADSP-2105), OKI ADPCM, ymfm
src/board	Midway T-Unit (DMA blitter, protection, Williams ADPCM sound) and Wolf Unit (security PIC, DCS)
src/app	SDL2 application: menu, ROM loading, video, shaders, netplay
tools/gspasm	assembler/linker compatible with TI GSPA/GSPLNK, written for this project
tools/build_roms.sh	rebuilds the games from the source repositories
tools/lod_palbpp.py, fix_narrow.py, fix_pwrd.py	make the 1995 LOAD2 output match the 1994 tools (see below)
tools/irw2gfx*.py, imgfile.py	LOAD2 image file helpers
tools/emu2-ems.patch	EMS support for emu2, needed by LOAD2.EXE
tools/headless	command-line test programs
dist/NBAJamRecomp	release folder (docs; the .exe is built here)

Building the application

Windows build (cross-compiled from Linux with llvm-mingw and SDL2 2.30 for mingw):

make BUILD=build/win CXX=x86_64-w64-mingw32-g++ build/win/libcore.a
make win SDL2W=/path/to/SDL2-2.30.x/x86_64-w64-mingw32     # -> dist/NBAJamRecomp/NBAJamRecomp.exe

Linux build: make linux-app SDL2L=/path/to/static-sdl2 → build/linux/NBAJamRecomp (x86-64, glibc 2.38+; SDL2 and libstdc++ linked statically).

Building the games from source

Needs bash, python3 and emu2 with tools/emu2-ems.patch (Linux, or WSL on Windows):

git clone https://github.com/historicalsource/nba-jam-tournament-edition repos/nba-jam-tournament-edition
git clone https://github.com/Asure/nba-jam-tournament-edition-SE        repos/nba-jam-tournament-edition-SE
git clone https://github.com/historicalsource/nba-hangtime              repos/nba-hangtime
tools/build_roms.sh repos /path/to/emu2 dist/NBAJamRecomp/data

The script assembles and links every game with gspasm, runs Midway's LOAD2.EXE to pack the art, compares the results with the original ROMs and writes data/<game>/.

What it took to get identical ROMs

• gspasm reproduces GSPA's quirks: TI operator precedence (| ^ like + -, & << >> like *), surplus macro arguments folded into the last parameter, and GSPLNK's 0x0000FFFF hole filling.
• T.E. art packing - the T.E. was packed in 1994 by an older LOAD2 that gave every image the bits per pixel of its palette, while the 1995 LOAD2 in the sources packs to the minimum. lod_palbpp.py adds PPP> n lines to the LOD files (otherwise name plates are noise).
• Narrow images - the 1995 LOAD2 pads images narrower than 3 pixels; fix_narrow.py removes the padding column and moves all later image addresses back.
• Second animation point - the 1995 LOAD2 writes -1 to the PWRD1..3 header fields (where the ball is held); fix_pwrd.py takes them from the .IMG files. Without it the ball floats and never bounces.

Licence

The code of this project is released under the BSD 3-Clause licence (see LICENSE). Third-party code: MAME CPU cores and ymfm (BSD 3-Clause), miniz (MIT / Unlicense), font8x8 (public domain), SDL2 (zlib). NBA JAM, NBA Hangtime and Midway are trademarks of their owners; this is a non-profit fan project not affiliated with them.

Credits

• Midway Games: the original games and the source code released by historicalsource
• Asure: NBA JAM T.E. Special Edition and its sources
• The MAME team, Aaron Giles (ymfm), dmsc (emu2)