From Sega Retro

Video game console emulator

System(s): Sega Mega Drive
OS: DOS, Windows, Linux, PowerPC
Developer: Markus Gietzen; Brian Verre (PowerPC)
Programmed in: Assembly, C
Last release date: (25 years ago)
Last version: 0.19

GenEm is a Sega Mega Drive emulator for DOS and Windows 9x programmed in 1996 and 1997 by Markus Gietzen. It's the second Mega Drive emulator released (the first one being Megadrive Emulator), and as such, has speed issues. A Linux version was released under the name XGenEm, which was based upon the (unreleased?) DOS version 0.21 source code. GenEm was ported to PowerPC computers by Brian Verre.

DOS version

The DOS version was the first emulator to feature (preliminary) sound emulation, although the YM2612 isn't exactly emulated. The emulator tries (and 95% of the times fails) to convert the voices, commands, etc. to the format of the OPL3-chip used on various Sound Blaster cards. If you have any other sound card, it won't give you FM sound. Additionally, although Z80 emulation is present, players must activate it with a switch in command prompt -z80, or for fake emulation, -fakez80. Games which require Z80 emulation to work properly (for example Sonic 2 or newer, which have the sound driver on Z80, or DAC samples in most games) must use the -z80 switch. The DAC emulation is, however, extremely buggy and slow.

It comes with 2 executables.

  • GENEM.EXE (older, slower but stable 68000-core written in C)
  • GENNEW.EXE (newer but experimental 68000-core written entirely in assembler)

Windows version

The Windows version seems to lack sound emulation, even though there is an option to enable the Z80. Timing is CPU-dependent and consequently will run too fast on newer computers.



Download GenEm
Multiple downloads available

0.11 for Linux (131 kB) (info)

Old versions

  • GenEm for DOS versions (info) (966 kB)
    • GenEm version 0.12 PUBLIC BETA (1996-09-05)
    • GenEm version 0.15 PUBLIC BETA (1996-09-25)
    • GenEm version 0.17 PUBLIC BETA (1996-11-16)
    • GenEm version 0.19 (1997-05-18)

Third-party versions

External links