jgenesis

Cross-platform multi-console emulator supporting a number of 8-bit and 16-bit gaming consoles.

Features

• Emulation for the following consoles:
  • Sega Genesis / Mega Drive
  • Sega CD / Mega CD
  • Sega Master System / Mark III
  • Game Gear
  • Nintendo Entertainment System (NES) / Famicom
  • Super Nintendo Entertainment System (SNES) / Super Famicom
  • Game Boy / Game Boy Color
• GPU-based renderer with integer prescaling and optional linear interpolation
• Configurable pixel aspect ratio for each console with several different options: accurate to original hardware/TVs, square pixels, and stretched to fill the window
• Support for the Sega Master System FM sound unit expansion
• Support for the Sega Genesis SVP chip, used in Virtua Racing
• Support for the most common NES mappers, plus a number of less common mappers
• Support for most SNES coprocessors (e.g. Super FX, SA-1, DSP-1, CX4, S-DD1, SPC7110)
• Support for both 3-button and 6-button Genesis controllers
• Support for keyboard controls and DirectInput gamepad controls
• Save states, fast forward, and rewind
• Some simple horizontal blur and naive anti-dither shaders for blending dithered pixel patterns, which were extremely common on these consoles due to limited color palettes and lack of hardware-supported transparency
• Optional 2x CPU overclocking for Sega Master System and Game Gear emulation
• Optional 2-4x GSU overclocking for SNES Super FX games
• Can run the Titan Overdrive and Titan Overdrive 2 demos for the Mega Drive

TODOs:

• Support multiple Sega CD BIOS versions in GUI and automatically use the correct one based on disc region
• Investigate and fix a few minor issues, like the EA logo flickering for a single frame in Galahad
• Support 24C64 EEPROM chips (used only in Frank Thomas Big Hurt Baseball and College Slam)

Dev Builds

The GitHub Actions workflow compiles release builds on every commit, which will stay available for 90 days afterwards: https://github.com/jsgroth/jgenesis/actions

Note that these builds are not always well-tested and may have bugs.

Dependencies

Rust

This project requires the latest stable version of the Rust toolchain to build.

SDL2

This project requires SDL2 core headers to build.

Linux (Debian-based):

sudo apt install libsdl2-dev

Windows:

• https://github.com/libsdl-org/SDL/releases

Build & Run

GUI:

cargo run --release --bin jgenesis-gui

CLI:

cargo run --release --bin jgenesis-cli -- -f <path_to_rom_file>

To view all CLI args:

cargo run --release --bin jgenesis-cli -- -h

To build with maximum optimizations (better runtime performance + smaller binary size at the cost of long compile time):

RUSTFLAGS="-C target-cpu=native" cargo build --profile release-lto

...After which the executables will be in target/release-lto/.

Screenshots

Sources

Sega Master System / Game Gear

• Z80 User Manual: https://map.grauw.nl/resources/cpu/z80.pdf
• The Undocumented Z80 Documented: http://www.myquest.nl/z80undocumented/z80-documented-v0.91.pdf
• Sega Master System architecture: https://www.copetti.org/writings/consoles/master-system/
• Sega Master System / Game Gear documentation: https://www.smspower.org/Development/Documents
• YM2413 application manual: https://www.smspower.org/maxim/Documents/YM2413ApplicationManual
• Reverse engineering of the YM2413: https://github.com/andete/ym2413

Sega Genesis / Mega Drive

• M68000 Family Programmer's Reference Manual: https://www.nxp.com/docs/en/reference-manual/M68000PRM.pdf
• Motorola 68000 Opcodes: http://goldencrystal.free.fr/M68kOpcodes.pdf
• Mega Drive / Genesis architecture: https://www.copetti.org/writings/consoles/mega-drive-genesis/
• Mega Drive official documentation: https://segaretro.org/Mega_Drive_official_documentation
• Sega Genesis hardware notes by Charles MacDonald: https://gendev.spritesmind.net/mirrors/cmd/gen-hw.txt
• Aggregating Community Research: https://gendev.spritesmind.net/forum/viewtopic.php?f=2&t=2227
• Mega Drive video timings: https://gendev.spritesmind.net/forum/viewtopic.php?f=22&t=519
• Genesis ROM header reference: https://plutiedev.com/rom-header
• Genesis - Going beyond 4MB: https://plutiedev.com/beyond-4mb
• SEGA Mega Drive / Genesis hardware notes by Kabuto: https://plutiedev.com/mirror/kabuto-hardware-notes
• Huge thread discussing and detailing the YM2612: https://gendev.spritesmind.net/forum/viewtopic.php?f=24&t=386
• Genesis EEPROM games: https://gendev.spritesmind.net/forum/viewtopic.php?f=25&t=206
• SVP documentation by notaz, as well as earlier documentation work by Tasco Deluxe: https://notaz.gp2x.de/docs/svpdoc.txt

Sega CD / Mega CD

• Mega CD official documentation: https://segaretro.org/Mega-CD_official_documentation
• ECMA-130 standard: https://www.ecma-international.org/publications-and-standards/standards/ecma-130/
• Thread discussing details of Mega CD emulation: https://gendev.spritesmind.net/forum/viewtopic.php?t=3020

NES

• 6502 Instruction Set: https://www.masswerk.at/6502/6502_instruction_set.html
• 6502 Hardware Manual: https://web.archive.org/web/20120227142944if_/http://archive.6502.org:80/datasheets/synertek_hardware_manual.pdf
• Documentation for the NMOS 65xx/85xx Instruction Set: https://www.nesdev.org/6502_cpu.txt
• Nintendo Entertainment System (NES) architecture: https://www.copetti.org/writings/consoles/nes/
• NESDev NES reference guide: https://www.nesdev.org/wiki/NES_reference_guide

SNES

• A 65816 Primer: https://softpixel.com/~cwright/sianse/docs/65816NFO.HTM
• Super Nintendo architecture: https://www.copetti.org/writings/consoles/super-nintendo/
• fullsnes - nocash SNES hardware specifications: https://problemkaputt.de/fullsnes.htm
• Anomie's SNES documents: https://www.romhacking.net/?page=documents&category=&platform=&game=&author=&perpage=20&level=&title=anomie&docsearch=Go
• SFC Development Wiki: https://wiki.superfamicom.org/

Game Boy / Game Boy Color

• Game Boy CPU (SM83) Instruction Set: https://gbdev.io/gb-opcodes/optables/
• Pan Docs: https://gbdev.io/pandocs/
• Game Boy Complete Technical Reference: https://gekkio.fi/files/gb-docs/gbctr.pdf
• Gameboy Sound Hardware: https://gbdev.gg8.se/wiki/articles/Gameboy_sound_hardware
• The Cycle-Accurate Game Boy Docs: https://github.com/geaz/emu-gameboy/blob/master/docs/The%20Cycle-Accurate%20Game%20Boy%20Docs.pdf
  • This contains some outdated/incorrect information but is still useful