Snes9x: The Portable Super Nintendo Entertainment System Emulator
Home page: www.snes9x.com
Changes Since Last Release
What You Will Need
Problems With ROMs
Converting ROM Images
Speeding up the Emulation
Changes Since Last Release
Check the CHANGES file for a complete history of Snes9x changes between
Snes9x is a portable, freeware Super Nintendo Entertainment System (SNES)
emulator. It basically allows you to play most games designed for the SNES
and Super Famicom Nintendo game systems on your PC or Workstation; which
includes some real gems that were only ever released in Japan.
Snes9x is the result of well over two years worth of part-time hacking,
coding, recoding, debugging, divorce, etc. (just kidding about the divorce
bit). Snes9x is coded in C++, with three assembler CPU emulation cores on the
i386 Linux, DOS and Windows ports.
Snes9x is better than a real SNES:
o Freeze a game at any position, then restore the game to that exact spot at
a later date - ideal for saving a game just before a difficult bit.
o Built-in cheat cartridge.
o Built-in peripheral emulation. The SNES mouse, Multi-player 5 and SuperScope
external add-ons are all emulated, they cost extra money with a real SNES.
o Stereo sound - yes I know the SNES produced stereo sound, but who actually
paid the inflated price for the special lead just so you could hear it?
o No more cartridge contact cleaning!
o Some SNES hardware features that be turned on and off during game play,
games might be using one of these features to deliberately make a section
of the game more difficult. Easy, just turn the feature off.
o Networked game play.
o Alter the speed of SNES games.
Snes9x is worse than a real SNES:
o Unless your computer is very fast (Pentium II+), some games just can't
hit every frame being rendered and the emulator starts to skip the drawing
of some frames to keep the emulator running at a constant speed - to you
it appears as if the graphics aren't moving as smoothly as they should.
o Not all games work; bugs and missing features cause some games to fail to
work or renders them un-playable.
o You have to wait for your computer to boot before you can play games,
no waiting on the real SNES!
o The SNES has an analog low-pass sound filter that give a nice bass to
all the sounds and music - Snes9x doesn't emulate this. If you have
a posh sound card, you could try fiddling with it mixer controls to produce
a similar effect. Turning on interpolated sound helps a lot.
- The 65c816 main CPU.
- The Sony SPC700 sound CPU.
- SNES variable length cycles.
- 8 channel DMA and H-DMA (raster effects).
- All background modes, 0 to 7.
- Sound DSP, with eight 16-bit stereo channels, compressed samples, hardware
attack-decay-sustain-release volume processing, echo, pitch modulation
and digital FIR sound filter.
- 8x8, 16x8 and 16x16 tile sizes, flipped in either direction.
- 32x32, 32x64, 64x32 and 64x64 screen tile sizes.
- H-IRQ, V-IRQ and NMI.
- Mode 7 screen rotation, scaling and screen flipping.
- Vertical offset-per-tile in modes 2, and 4.
- Horizontal offset-per-tile in modes 2, 4 and 6.
- 256x224, 256x239, 512x224, 512x239, 512x448 and 512x478 SNES screen
- Sub-screen and fixed colour transparency effects.
- Mosaic effect.
- Single and dual graphic clip windows, with all four logic combination modes.
- Colour effects only inside a window.
- 128 8x8, 16x16, 32x32 or 64x64 sprites, flipped in either direction.
- SNES palette changes during frame (15/16-bit internal rendering only).
- Direct colour mode - uses tile and palette-group data directly as RGB value.
- Super FX, a 21/10MHz RISC CPU found in the cartridge of several games.
- SNES mouse.
- SuperScope (light gun) emulated using computer mouse.
- Multi-player 5 - allowing up to five people to play games simultaneously on
games that support that many players.
- Game-Genie, Action Replay and Gold Finger cheat codes.
- Multiple ROM image formats, with or without a 512 byte copier header.
- Single or split images, compressed using gzip, and interleaved in one of two
- Auto S-RAM (battery backed RAM) loading and saving.
- Freeze-game support, now portable between different Snes9x ports.
- Interpolated sound.
- Only partial DSP1 support, enough to play Mario Kart but no more. The DSP1
is a math co-processor chip that was inside the cartridge of some games,
notably Mario Kart and Pilot Wings.
- Any other odd chips that manufactures sometimes placed inside the
cartridge to enhance games and as a nice side-effect, also act as an
anti-piracy measure, e.g. S-DD1, C4, etc.
- Pseudo hi-res. mode - SNES hardware uses interpolation to give apparent
increase in horizontal resolution, use one of the output image processing
options to get the same effect.
- Mosaic effect on mode 7.
- A couple of SPC700 instructions that I can't work exactly out what they
- Fixed colour and mosaic effects in SNES hi-res. (512x448) modes.
- Offset-per-tile in mode 6. Luckily I haven't found a game that uses it, yet.
What You Will Need
Windows 95, 98 or NT with at least DirectX 6 installed running on a modern,
fast (e.g. Pentium 200) computer with at least 16Mb of RAM. Some games
require another CPU to be emulated and/or make heavy use of colour
translucency effects, so an even faster computer may be required to get an
acceptable frame rate.
If you want SNES sound emulation, you'll need a DirectSound compatible sound
card - virtually all modern PCI sound cards are DirectSound compatible.
Snes9x's full-screen mode uses DirectDraw to switch to the required resolution
and depth, but if you intend to use the Windowed mode, you must have your
desktop depth set to 256 colours if translucency emulation and 16-bit
rendering are switched off and not required or hi-colour mode (32768/65536
colours) if translucency effects are required. This requirement will be
removed in later releases.
If you have a Voodoo 3dfx card, Snes9x can use this hardware to stretch and
filter the relatively lo-resolution SNES image to fill your computer screen.
Access to SNES ROM images in *.smc, *.sfc, *.fig or *.1, *.2, or sf32xxxa,
sf32xxxb, etc., format otherwise you will have nothing to run!
Some home-brewed ROM images can be downloaded from http://www.snes9x.com. To
find commercial games, you could try a web search engine and some imaginative
use of search strings, alternatively, I've heard http://www.cherryroms.com is
good place to try. Please note, it is illegal in most countries to have
commercial ROM images without also owning the actual SNES ROM cartridge.
Using explorer, locate the directory where you un-zipped the snes9xw.exe and
snes9xw.dll files and double-click on the snes9xw.exe executable.
Alternatively you could create a shortcut to Snes9x and drag that icon out
onto your desktop.
Use the Open option from the File menu to open the ROM load dialog. The dialog
allows you to browse your computer to locate the directory where you have
stored your SNES games. Double-click on a ROM image to load it and start the
SNES ROM images come in lots of different formats, depending on the copier
device that was originally used to create the image amongst other things, and
sometimes Snes9x has trouble auto-detecting the exact ROM format. Try playing
around with the values of the combo boxes in the ROM load dialog if the game
doesn't appear to work after its been loaded. In particular, games making use
of the Super FX RISC processor seem to be mostly in an odd interleaved format
that Snes9x has trouble auto-detecting, try selecting 'Interleave mode 2' from
the load ROM dialog if you have a Super FX game that isn't working.
On a real SNES players controlled games using an 8-button digital joy-pad; on
Snes9x you can use your computer's keyboard (the default) or any joystick
or controller device supported by Window's DirectInput. The default key
mapping for joy-pad 1 is:
'up arrow' Up direction
'down arrow' Down direction
'left arrow' Left direction
'right arrow' Right direction
'a' TL button
'z' TR button
's' X button
'x' Y button
'd' A button
'c' B button
'return' Start button
'space' Select button
The real SNES allowed up to five joy-pads to be plugged in at once via a
special adaptor, although there are only a few games that actually supported
that many players. Having five people crowd around the keyboard would not be
much fun, and anyway, all keyboards have a limit on the number of keys that
can be pressed simultaneously and still be detected correctly; much better to
use multiple joysticks. Add support for your joystick and calibrate it using
Windows joystick applet from the Windows control panel before starting Snes9x,
then use Joy-pad Config dialog in Snes9x to customise the keyboard/joystick to
SNES joy-pad mappings.
Some games can take a very long time to complete from start to finish so
many had some RAM and a battery fitted inside the game pack that allowed the
player to save his progress in a game at predefined places throughout the
game. Snes9x emulates this by saving the contents of the emulated
battery-backed RAM into a file when you load a new game or exit Snes9x. The
file is automatically re-loaded the next time you play the game.
Snes9x also provides freeze-files, these are files that saves a game's
position at any point in the game, not just at predefined places chosen by
the game's designers - ideal for saving your game just before a tricky bit!
During a game, press Shift + function key 1 - 10 to save a game, and just
function key 1 - 10 to load it again.
Freeze game files and S-RAM save files are normally read from and written to
the directory where the ROM image was loaded from, but sometimes this is not
desirable or possible, especially if its a CD-ROM! At the moment there is no
GUI option to change the directory, but, if you've used regedit.exe before, you
can force Snes9x to save freeze files and S-RAM files into a particular
directory by storing its pathname in the registry key:
"HKEY_CURRENT_USER\Software\Emulators\Snes9X\1.19a\Freeze File Directory"
While the emulator is running:
'Escape' Show/hide the menubar.
'Pause' Pause the emulator
'tab' Toggle between full-screen and windowed mode.
'0' Toggle H-DMA emulation on/off.
'1' Toggle background 1 on/off.
'2' Toggle background 2 on/off.
'3' Toggle background 3 on/off.
'4' Toggle background 4 on/off.
'5' Toggle sprites (sprites) on/off
'6' Toggle swapping of joy-pad one and two around
'7' Rotate between Multi-player 5, mouse on port 1,
mouse on port 2 and SuperScope emulation.
'8' Toggle background layer priorities for backgrounds
involved in sub-screen addition/subtraction.
'9' Toggle transparency effects on and off - only if
16-bit screen mode selected.
'Backspace' Toggle emulation of graphics window effects on/off.
Shift+'F1-F10' Quick save a freeze game file.
'F1-F10' Quick load a freeze game file, restoring a game to an
Alt or Ctrl+'F4' -> 'F11' Toggle sound channels on/off.
Alt or Ctrl+'F12' Turn on all sound channels.
The Super FX is a 10/21MHz RISC CPU developed by Argonaut Software used as a
game enhancer by several game tiles. Support is still a little buggy but most
games work very well, if a little slowly. Released SNES Super FX games included
Yoshi's Island (best single-player game on SNES, if you like platform games),
Doom, Winter Gold, Dirt Trax FX, StarFox, Stunt Race FX and Vortex. If you're
lucky, you might find a copy of the unreleased Starfox 2 image floating around.
Lots of Super FX ROM images available are in an odd interleaved format that I
haven't worked out how to auto-detect. If your ROM image isn't working try
selecting the Interleave mode 2 option on the ROM load dialog before loading a
The SA-1 is a fast, custom 65c816 8/16-bit processor, the same as inside the
SNES itself, but clocked at 10MHz compared to a maximum of 3.58MHz for the CPU
inside the SNES.
The SA-1 isn't just a CPU, it also contains some extra circuits developed by
Nintendo which includes some very fast RAM, a memory mapper, DMA, several
real-time timers, and the region lock-out chip.
Snes9x includes emulation of most features of the SA-1, enough to play Mario
RPG. The chip seems to be used in several other games that Nintendo released
in 1996 and beyond, notably Kirby Superstar and Paradius 3, but since no
complete ROM images of these games exist, I'm unable to test if they work on
Problems With ROMs
If the emulator just displays a black screen for over 10 seconds, then one
of the following could be true:
1) If its a Super FX game, chances are its in interleaved2 format, try
switching to "Interleaved mode 2" on the ROM load dialog before loading the
2) Someone has edited the Nintendo ROM information area inside the ROM image
and Snes9x can't work out what format ROM image is in. Try playing
around with the ROM format options on the ROM load dialog.
3) The ROM image is corrupt. If you're loading from CD, I know it might
sound silly, but is the CD dirty?
4) The original SNES ROM cartridge had additional hardware inside that is not
emulated yet and might never be - e.g. Street Fighter Alpha 2 (S-DD1),
Megaman X2 and Megaman X3 (C4).
The following ROMs are known currently not to work with any version of Snes9x:
- All DSP 1 games except Mario Kart (e.g. Pilotwings, Ballz 3d, Topgear 3000)
- Street Fighter Alpha 2, Star Ocean (missing S-DD1 emulation)
- Megaman X2 and X3 (missing C4 emulation)
- Exhaust Heat2 (custom co-processor)
- Metal Combat (OBC1)
No sound coming from any SNES game using Snes9x? Could be any or all of
- If all sound menu options are greyed out, Snes9x couldn't initialise
DirectSound. Make sure DirectX 6 or above is installed and your sound card
is supported by DirectX. Installing the latest drivers for your sound card
might help. Another Windows application might have opened DirectSound in
exclusive mode, in which case you will need to stop that application and
- The sound card's volume level might be set too low. Snes9x doesn't alter the
card's master volume level so your might need to adjust it using the sound
card's mixer controls usually available from the task bar or start menu.
- Make sure your speakers and turned on, plugged in and the volume controls are
set to a suitable level.
General sound problems:
- A continuous crackling sound can be heard. Trying increasing the sound
buffer size from the sound menu. If you need to set the value above 100ms to
get clean sound then you will also need to enable sync-sound mode or SNES
sound emulation will suffer.
- Sound quality is poor on all games. You might have a noisy sound card
(usually cheap cards), turning on interpolated sound, sync-sync and/or
increasing the playback rate might help.
- Sound seems to have gaps. Sometimes, when changing sound settings, either
DirectSound or Snes9x messes up (not sure which) and Snes9x losses sound
playback synchronisation. Try changing the playback rate to a different
value and back again or quit and then restart Snes9x.
- Sound in a few games sounds crackly. Try turning off sync-sound and/or
interpolated sound - both seem to have problems with a few games.
- Sound is awful in all games. You might have selected a playback rate/stereo/
8-bit/16-bit combination that your sound card can't cope with. Try setting
8-bit mono @22KHz from the sound menu and if that cures the problem, try
other combinations until you find the best setting that works on your sound
Converting ROM Images
If you have a ROM image in several pieces, simply rename them so their
filename extensions are numbered: e.g. game.1, game.2, etc. Then, when
loading the ROM image, just specify the name of the first part; the remaining
parts will be loaded automatically.
If they are already in the form sf32xxxa, sf32xxxb, etc., you don't even have
to rename them; just choose the name of the first part from the ROM load
dialog, as above.
Emulating an SNES is very compute intensive, with its two or three CPUs,
an 8 channel digital sound processor with real-time sound sample decompression
and stereo sound, two custom graphics processors, etc.
If you only have a 486 machine, you will need to stick to using only 8-bit
graphics and minimal or no sound. Disabling the joystick support will also
Full-screen mode is generally faster than windowed mode.
Enabling one of the output image processing modes from the Display Config
dialog can slow down overall emulation speed greatly depending on the type of
game and video RAM speed. Enabling the stretch image option further reduces
If you want the SNES image to fill your computer screen and want maximum speed,
use the 3dfx bi-linear option if you have a Voodoo 3dfx card, or select output
image mode as none and check the full-screen and stretch image options.
Lowering the sound playback rate, selecting 8-bit mono sound or turning off
interpolated and sync-sound modes will also help boost emulation speed.
- Jerremy Koot for all his hard work on current and previous versions of
Snes96, Snes97 and Snes9x.
- Ivar for the original Super FX C emulation, DSP1 emulation work and
information on both chips.
- zsKnight and _Demo_ for the Intel Super FX assembler code.
- zsKnight and _Demo_ for all the other ideas I've nicked off them; they've
nicked lots of my ideas and information too!
- Kreed for his excellent image enhancer routines.
- DiskDude's SNES Kart v1.6 document for the Game Genie(TM), Gold Finger and
Pro Action Replay cheat system information.
- Lord ESNES for some nice chats and generally useful stuff.
- Lee Hyde (firstname.lastname@example.org) for his quest for sound information and
the Windows 95 icon.
- Shawn Hargreaves for the rather good Allegro 3.0 DOS library.
- Robert Grubbs for the SideWinder information - although I didn't use his
actual driver in the end.
- Steve Snake for his insights into SNES sound sample decompression.
- Vojtech Pavlik for the Linux joystick driver patches.
- Maciej Babinski for the basics of Linux's DGA X server extensions.
- Alexander Larsson for the GGI Linux port code.
- Harald Fielker for some sound interpolation code (not included in this
release due to problems).
- Takehiro TOMINAGA for many speed up suggestions and bug fixes.
- Predicador for the Windows icon
Nintendo is a trademark.
Super NES, SuperScope and Super FX are a trademarks of Nintendo.
Sun, Solaris and Sparc are all trademarks of Sun Microsystems, Inc.
Game Genie is a trademark of Lewis Galoob Toys, Inc.
MS-DOS and Windows 95 are trademarks of Microsoft Corp.
Intel, Pentium and MMX are all trademarks of Intel Corp.
Sony is a trademark of Sony Corp.
UNIX is a trademark of someone, I forget who, but its not AT&T, they sold it.
Glide is a trademark of 3Dfx Interactive, inc.