Wolfenstein 3D for the fx-CG50

Kelli's Last Wolfenstein 3D for the fx-9860 series, running on the fx-CG50 / Graph 90+E.

Convert it in your browser: https://hexbinoct.github.io/wolf3d-cg50/

1. Download file 2 (the SH4 version) of the game from Planète Casio.
2. Drop it on the page above. You get Wolf3D.g3a, made in your browser; nothing is uploaded.
3. Copy Wolf3D.g3a to the calculator in USB Flash mode.

Keys: arrows move and turn, SHIFT shoots, ALPHA opens doors, F1/F2 knife/gun, F6/F5 hide/show the status bar, MENU pauses, EXIT quits, + and − change the speed.

How it works

The game's source was never published, so it isn't rewritten: its own machine code runs on the fx-CG50. Both calculators use SuperH processors, and both operating systems load an add-in at 0x00300000, so the code sits at the address it was built for. A shim (shim/) handles what differs:

• the fx-9860 system calls (timers, files, keyboard) are redirected to the fx-CG50's;
• the routine that sent the 128×64 screen to the monochrome LCD now draws it three times larger in colour VRAM;
• quitting returns to the main menu instead of resetting;
• the game has no frame limiter, so the shim slows it to fx-9860 pace (adjustable with + and −).

The page (index.html, convert.js) contains no part of the game. payload.js is a complete .g3a with zeros where the game goes, plus the patches that redirect it to the shim. The page copies your copy of the game into it and recomputes the checksum.

Building

Needs the fxSDK toolchain (sh-elf-gcc, fxgxa), Python 3 and Node.

make GAME=WOLF.g1a          # payload.js
make check GAME=WOLF.g1a    # converter output must equal the fxgxa build
node tools/convert.cjs WOLF.g1a Wolf3D.g3a

Credits

The game is by Kelli. This repository only holds the shim and the converter, under the GPL-3.0 (LICENSE). Not affiliated with Casio or id Software.