Snes9x_orig_README.txt

Snes9x: The Portable Super Nintendo Entertainment System Emulator
=================================================================
v1.39 13-SEP-2001
=================

Home page: http://www.snes9x.com

Contents
========
Changes Since Last Release
Introduction
What's Emulated
What's Not
What You Will Need
Getting Started
Keyboard Controls
Joystick Support
Game Saving
Netplay Support
Cheat Support
Super FX
S-DD1
S-RTC
SA-1
C4
3dfx Support
Problems With ROMs
Sound Problems
Converting ROM Images
Speeding up the Emulation
Getting Help
Credits

Changes Since Last Release
==========================

Check the CHANGES file for a complete history of Snes9x changes between
versions.

Introduction
============

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. The games
include some real gems that were only ever released in Japan.

Snes9x is the result of well over three years worth of part-time hacking,
coding, recoding, debugging, etc. 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 on some ports.
o Speed up or slow down SNES games.
o Save screen shots to impress(?!) your friends. (Alt + PrtSc, then paste
  image into paint program, save or print from there)

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 could.
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 analogue 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.

What's Emulated
===============
- The 65c816 main CPU.
- The Sony SPC700 sound CPU.
- SNES variable length machine 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
  resolutions.
- Sub-screen and fixed colour blending effects.
- Mosaic effect.
- Single and dual graphic clip windows, with all four logic combination modes.
- Colour blending effects only inside or outside 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.
- S-DD1, a data decompression chip used only in Star Ocean and Street Fighter 2
  Alpha. Snes9x's implementation, like zsnes's, is a bit of a cheat - nobody 
  can figure out the compression algorithm the chip uses, so instead the
  actual chip was used decompress the data, the data saved and made available
  for download. The decompressed graphics packs must be downloaded in order to
  play the two S-DD1 games.
- S-RTC, a real-time clock chip. Dai Kaijyu Monogatari II is the only game
  that uses it.
- SA-1, a faster version of CPU found in the main SNES unit together with some
  custom game-accelerator hardware.
- C4, a custom Capcom chip used only in Megaman X2 and X3. Its a sprite scaler/
  rotator/line drawer/simple maths co-processor chip used to enhance some
  in-game effects.
- Partial DSP-1 support, enough to play Mario Kart, Pilotwings, SD Racer,
  Suzuka 8 Hours and a few other DSP-1 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 and Action Replay 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
  ways.
- Auto S-RAM (battery backed RAM) loading and saving.
- Freeze-game support, now portable between different Snes9x ports.
- Interpolated sound.

What's Not
==========
- Only partial DSP-1 support, enough to play Mario Kart, Pilotwings and a few
  other DSP-1 games. The DSP-1 is a math co-processor chip that was inside the 
  cartridge of several games. There are a few versions of the chip, but only
  the first version is supported by Snes9x.
- 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.
- 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 
  should do.
- 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 and OpenGL installed running on
a modern, fast (e.g. Pentium 200 or higher) computer with at least 32Mb 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're running the original version of Windows 95 you will need to download
Microsoft's OpenGL upgrade kit from there web site; they keep moving the exact
location, but last time I looked I found it by using the following method:
http://www.microsoft.com -> support -> Product support options ->
download centre -> keyword search: OpenGL, product: Windows 95; the OpenGL
DLL install package was the first option in the list after pressing Find It!

If you want SNES sound emulation, you'll need a DirectSound compatible sound
card - virtually all modern PCI sound cards are DirectSound compatible - or
use FMOD's older Windows WAVE sound driver.

Snes9x's full-screen mode uses DirectDraw to switch to the required resolution
and depth, but if you intend to use the Windowed mode, for maximum emulation 
speed you should 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.

If you have a Voodoo 3dfx card, Snes9x can use this hardware to stretch and
smooth the relatively lo-resolution SNES image to fill your computer screen.
Newer nvidia cards can do the same trick, just select stretch image option.
There is also an OpenGL display output mode that can stretch and smooth
the SNES image. If your OpenGL hardware supports 16-bit textures (most do),
OpenGL mode is as fast, or faster than Voodoo 3dfx mode.

Software
--------
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,
http://www.pe2000.net and http://www.emuinfinity.com are good places to try.
Please note, it is illegal in most countries to have commercial ROM images
without also owning the actual SNES ROM cartridge.

Getting Started
===============

Launch Snes9x from the Windows Start menu if you used the package install
method; alternatively use Windows explorer to locate the directory where you
un-zipped the snes9xw.exe, fmod.dll and snes9xw.dll files and double-click on
the snes9xw.exe executable. You could create a shortcut to Snes9x and drag 
that icon out onto your desktop.

Loading Games
-------------
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 name or single-click and 
then press Load to load and start the game.

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.
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 that use
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.

SNES Joypad Emulation
---------------------
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 or NetPlay. 

Keyboard/Joystick Config
------------------------

Add support for your joystick and calibrate it using Windows' joystick applet
from the Windows control panel before starting Snes9x, then use Joy-pad 
Configuration dialog in Snes9x to customise the keyboard/joystick to SNES 
joy-pad mappings. The dialog is easy to use: select which SNES joy-pad you are
configuring using the combo box (#1 to #5), click on the text box next to the
'UP' SNES joy-pad button and then press the key on the keyboard or 
button on your joystick that you would like to perform the UP action. The
focus will automatically move on to the 'RIGHT' text box, press the key or
joystick button that you want to perform the RIGHT action, and so on until 
you've customised all the SNES joy-pad buttons.

If you're using the keyboard, you might want to also program four keys for
diagonal movement - I'm told it helps with beat-em-up type games. Click on the
each of the blue-coloured diagonal text boxes in turn and press a key on the
keyboard you would like to perform the action. Using the numeric keypad for
direction keys might be useful in this case.

Additional Keyboard Controls
============================

While the emulator is running:
'Escape'                Show/hide the menu-bar.
'Pause'                 Pause the emulator

Alt+'Return'            Toggle between full-screen and windowed mode.

'`'			Superscope turbo button.
'~'			Superscope pause button.

'Tab'                   Turbo mode (fast forward) - for skipping long intros.

'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 or higher screen mode selected.
Shift+'9'		Toogle mode 7 bi-linear filtering on and off.
'Backspace'		Toggle emulation of graphics window effects on/off.

Shift+'F1-F9 '          Save a freeze game file.
'F1-F9'                 Load a freeze game file, restoring a game to an
                        exact position.

Ctrl+'F4' -> 'F11' 	Toggle sound channels on/off.
Ctrl+'F12'              Turn on all sound channels.

Shift+'+'               Increase emulated frame time by 1ms - slowing down
                        the game. (auto-frame skip only)
Shift+'-'               Decrease emulated frame time by 1ms - speeding up the
                        game. (auto-frame skip only)

'+'                     Increase frame rendering skip rate, making the screen
                        updates more jerky but speeding up the game. 
'-'                     Decrease frame rendering skip rate, making the game
                        update more smoothly, but potentially slowing down the
                        game. Repeatedly pressing the key will eventually
                        switch to auto-frame skip rate where the rate is
                        dynamically adjusted to keep a constant game play
			speed.

Several of the menu items also have keyboard accelerators; browse the menus
to see what they are.

Joystick Support
================

Configure and calibrate your joystick/joy-pad using Windows joystick applet in
the control panel BEFORE starting Snes9X, then use Snes9X's joy-pad config 
dialog available from the Options menu to map your joystick/joy-pad's buttons
to the emulated SNES joy-pad(s) buttons. See 'Keyboard/Joystick Config' above
for details.

Game Saving
===========

Many SNES games could take a very long time to complete from start to finish so
they allowed your progressed to be saved into RAM fitted inside the game pack;
the RAM contents were backed up by a battery when the SNES was switched off or
the game removed. Snes9x simulates 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 then 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!
Snes9x provides 9 save slots; during a game, press Shift + F1 to F9 to save a
game, and just F1 to F9 to load it again later.

Freeze game files and Save-RAM (S-RAM) save files are normally written to and
read from the folder where the ROM image was located, but sometimes this is not
desirable or possible, especially if its a CD-ROM, which is of course 
read-only! You can change the folder where Snes9X saves and loads S-RAM and
freeze-files using the Settings Dialog, available from the Options menu.

Snes9x uses its own unique format for freeze-files, as does ZSNES, but Snes9x
can also load ZSNES format freeze-files. Just copy the ZSNES freeze files into
your save directory and, if the native format Snes9x freeze file doesn't exist
(<rom image name>.00X where X is a digit), Snes9x will try to load the
corresponding ZSNES freeze file instead (<rom image name>.zsX where X is a 't'
or a digit). When you freeze a game position after loading a ZSNES format
freeze file, Snes9x will save it in native Snes9x format.

Netplay Support
===============

This support should currently be considered beta. Netplay support allows
up to five players to sit in front of different computers and simultaneously
play the same game, or just watch someone else play a game. All the computers
have to be connected to a network that allows TCP/IP traffic to flow between
them; this includes a local Ethernet-style network, a modem connection to
another machine, a Windows direct-cable connection, or, if you're lucky and 
have short ping times, the Internet.

Its currently easier if you use Snes9x in windowed mode while using Netplay,
mainly because Netplay currently displays status information in the window's
title bar, and it might be necessary to setup a separate chat application so
you can talk to the other players when deciding what game to play next.

One machine has to act as a server which other players (client sessions) 
connect to. The 'master' player, player 1, uses the server machine; the master
decides what game to play. The server machine should be selected to be the
fastest machine on the fastest connection in the group taking part due to the
extra functions it has to perform.

Load up a game, then select the 'Act as server' option from the Netplay menu
to become a Netplay server; the 'network', in whatever form it takes, will
need to be initialised, if necessary, before you do this. Then just wait for 
other players to connect...

Clients connect to the server using the 'Connect to server...' dialog, again
available from the Netplay menu. Type in the IP address or host name of the
machine running the Snes9x server session and press OK. The first remote client
to connect will become player 2, and so on. Start Menu->Run->winipcfg will tell
you your current IP address, but note that most dial-up ISPs will allocate you
a new IP address each time you dial in.

If the server has the 'Send ROM Image to Client' option checked, it will send
the client a copy of the game it is currently playing; don't enable this option
when using a slow network - sending 4Mbytes+ to several clients will takes ages
when using a modem! If the option is not checked the server will request the
client loads up the correct game first before joining the game.

Once the client has got a copy of the game the server is playing, the server
will then either send it S-RAM data and reset all players' games if the 
'Sync Using Reset Game' option is checked, or send it a freeze file to get the
new client in sync with the other player's progress in a game.

If the master player loads a different game, the server will either 
automatically send remote clients a copy, or request that they load the game.
If the master player loads a freeze file, the server will automatically send
that to remote clients as well.

Client sessions must be able to keep up with the server at all times - if they
can't, either because the machine is just too slow, or its busy, the games
will get out of sync and it will be impossible to successfully play a 
multi-player game...

...To make sure this doesn't happen, don't move the Snes9x window unnecessarily
and don't use Ctlt+Alt+Del to display the task manager while playing. Also stop
any unnecessary applications and as many background tasks as possible. Even
something as simple as a text editor might periodically write unsaved data to
the disk, stealing CPU time away from Snes9x causing it to skip a frame or
delay a sound effect; not a problem for most games, but the Bomberman series
(the best multi-player games on the SNES) sync the game to sound samples 
finishing. Turning off 'Volume envelope height reading' from the Sound Options
dialog might help with this problem.

Cheat Support
=============

Use the Cheat Code Entry and Editor dialog from the Cheats menu to enter 
Game Genie or Pro-Action Reply cheat codes. Cheat codes allow you to, 
surprisingly, cheat at games; they might give you more lives, infinite health,
enable special powers normally only activated when a special item is found,
etc.

Many existing Game Genie and Pro-Action Reply codes can be found at:
http://vgstrategies.miningco.com/games/vgstrategies/library/ggn/bl_ggnsnes.htm

Type in a Game Genie or Pro-Action Reply code into the "Enter Cheat Code" text
edit box and press <Return>. Be sure to include the '-' when typing in a Game
Genie code. You can then type in an optional short description as a reminder
to yourself what function the cheat performs. Press <Return> again or click the
Add button to add the cheat to the list. 

Note that the Add button remains insensitive while "Enter Cheat Code" text 
edit box is empty or contains an invalid code. The cheat code is always 
translated into an address and value pair and displayed in the cheat list as
such.

Beware of cheat codes designed for a ROM from a different region compared to
the one you are playing or for a different version of the ROM; the source of
the cheats should tell you which region and for which version of the game they
were designed for. If you use a code designed for a different region or version
of your game, the game might crash or do other weird things.

It is also possible to enter cheats as an address and value pair; some users
have requested this functionality. Type in the address into the "Address"
text edit box then type the value into the "Value" text edit box. The value is
normally entered in decimal, but if you prefix the value with a '$' or append
a 'h' then you can enter the value in hex.

Double-clicking on an cheat line from the list in the dialog or clicking on 
the "En" column, toggles a individual cheat on and off. All cheats can be
switched on and off by checking and unchecking the "Apply cheats" item from
the Cheat menu.

Selecting a cheat from the list causes its details to be filled into the text
edit boxes in the dialog box; the details can then be edited and the Change
button pressed to commit the edits. Note that the "Enter Cheat Code" text edit
box always redisplays the cheat code as a Pro-Action Replay code regardless of
whether you originally entered it as a Game Genie or Pro-Action Replay code.

Selecting a cheat from the list then pressing the Delete button permanently
removes that cheat.

Cheats are saved in .cht files stored in the Freeze File Directory and are 
automatically loaded the next time a game with the same filename is loaded.
The format for the .cht files is the same format as used by the other excellent
SNES emulator, ZSNES.

Snes9X also allows new cheats to be found using the Search for New Cheats
dialog, again available from the Cheats menu. The easiest way to describe the
dialog is to walk through an example.

Cheat Search Example
--------------------
Lets give ourselves infinite health and lives on Ocean's Addams Family 
platform game:

Load up the game, keep pressing the start button (Return key by default) to 
skip past the title screens until you actually start playing the game. You'll
notice the game starts with 2 health hearts and 5 lives. Remember that
information, it will come in useful later.

Launch the cheat search dialog for the first time, Alt+A is its accelerator.
Press the Reset button just in case you've used the dialog before, leave the 
Search Type and Data Size radio boxes at their default values and press OK.

Play the game for a while until you loose a life by just keep walking into 
baddies, when the game restarts and the life counter displays 4, launch the 
cheat search dialog again but this time press the Search button rather than 
Reset. The number of items in the list will reduce, each line shows a memory
location, its current value and its previous value; what we're looking for is
the memory location where the game stores its life counter. 

Look at address line 7E00AC, its current value is 4 and its previous value was
5. Didn't we start with 5 lives? Looks interesting...

Note that some games store the current life counter as displayed on the screen,
while others store current number of lives minus 1. Looks like Addams Family
stores the actual life count as displayed on the screen.

Just to make sure you've found the correct location, press OK on the dialog, 
and play the game until you loose another life. Launch the search dialog again
after the life counter on screen has been updated and press the Search
button. Now there's even fewer items in the list, but 7E00AC is there again,
this time the current value is 3 and the previous value was 4. Looks very much
like we've found the correct location.

Now that we're happy we've found the correct location, click on the 7E00AC
address line in the list and then press the Add Cheat button. Another dialog,
Cheat Details, will be displayed. Type in a new value of say 5, this will be
number of lives that will be displayed by the lives counter. Don't be greedy;
some games display a junk life counter or might even crash if you enter a
value that's too high; Snes9X keeps the value constant anyway, so even if you
do loose a life and life counter goes down by one, less than 20ms later,
Snes9X resets the counter back to the value you chose!

If the memory location you add a cheat on proves to be wrong, just go to the
Cheat Code Editor dialog and delete the incorrect entry.

Now lets try and find the Addams Family health counter. While two hearts are
displayed on the screen, visit the cheat search dialog and press the Reset 
button followed by OK. Play the game until you loose a heart by touching a
baddie, then visit the cheat search dialog again.

Press the Search button to update the list with all memory locations that have
gone down in value since the last dialog visit. We're going to have to try and
find the heart memory location now because there were only two hearts to start
with.

Look at address line 7E00C3, its current value is 1 and its previous value was
2. Scrolling through the list doesn't reveal any other likely memory locations,
so lets try our luck. Click on the 7E00C3 line, press the Add Cheat button and
type in a new value of say 4 into the dialog that appears and press OK. Press 
OK on the Search for New Cheats dialog to return to the game.

At first sight it looks like 7E00C3 wasn't the correct memory location because
the number of hearts displayed on screen hasn't gone up, but fear not, some
games don't continually update health and life displays until they think they
need to. Crash into another baddie - instead of dying, the number of hearts 
displayed jumps up to 4! We've found the correct location after all!

Now every time you play Addams Family you'll have infinite lives and health.
Have fun finding cheats for other games.

Super FX
========
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,
but its sound code is corrupt and you'll need to disable sound CPU emulation to
play it.

Lots of Super FX ROM images available are in an odd, interleaved format that I
haven't worked out an easy way to auto-detect. If Snes9x detects that a 
Super FX game crashes (by executing a BRK instruction), it automatically 
assumes the ROM is in this odd format and de-mangles the ROM and tries to run
it again. If your ROM image isn't working, you could try selecting the 
Interleave mode 2 option on the ROM load dialog before loading the game to help
out Snes9x.

S-DD1
=====
The S-DD1 is a custom data decompression chip that can decompress data in real-
time as the SNES DMA's data from the ROM to RAM. Only two games are known to
use the chip: Star Ocean and Street Fighter Alpha 2.

The chip uses some unknown compression algorithm, so to actually support the 
two S-DD1 games, pre-decompressed graphics packs must be downloaded from
http://dejap.zsnes.com, unpacked, and the resultant folder copied into the 
same folder that Snes9x normally loads and saves game freeze-files and S-RAM
files. To prevent copyright problems, the packs must be unpacked and decoded
using a special tool also available from the same site. The tool needs access
to the original game ROM image while it decodes the graphics.

SA-1
====
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 and, several
real-time timers.

Snes9X includes emulation of most features of the SA-1, enough to play all SA-1
games I've located so far, these include Mario RPG, Kirby Superstar and 
Paradius 3.

C4
==

The C4 is custom Capcom chip used only in the Megaman X2 and Megaman X3 games.
It can scale and rotate images, draw line-vector objects and do some simple
maths to rotate them.

Snes9x's C4 emulation is a direct copy of the ZSNES C4 emulation; Intel-based
ports even make use of ZSNES code. Without zsKnight's hard work, Snes9x would
not have C4 emulation. Many thanks go to him.

Problems With ROMs
==================

If the emulator just displays a black screen for over 10 seconds after you've
loaded a ROM image, then one of the following could be true:

1) You just loaded some random ROM image you've downloaded from the Internet
   and it isn't even a SNES game or you only downloaded part of the image. 
   Snes9x only emulates games designed for the Super NES, not NES, or 
   Master System, or Game Boy, or <insert your favourite old games system here>.
2) 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
   game.
3) 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.
4) The ROM image is corrupt. If you're loading from CD, I know it might
   sound silly, but is the CD dirty? Clean, un-hacked ROM images will display
   [checksum ok] when first loaded, corrupt or hacked ROMs display 
   [bad checksum].
5) The original SNES ROM cartridge had additional hardware inside that is not
   emulated yet and might never be.

The following ROMs are known to currently not to work with any version of Snes9x:
- All games that use later versions of the DSP-1 chip (e.g. Ballz 3d, 
  Topgear 3000)
- Exhaust Heat2 (custom co-processor)
- Metal Combat (OBC1)

Sound Problems
==============

No sound coming from any SNES game using Snes9x? Could be any or all of
these:

- If all sound menu options are greyed out, or an error dialog about Snes9x not
  being able to initialise DirectSound is displayed - then DirectSound could
  not initialise itself. 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 or 
  opened the Windows WAVE device - WinAmp uses the Windows WAVE device by 
  default - in which case you will need to stop that application and then 
  restart Snes9x. It is possible to switch WinAmp to use DirectSound, in
  which case both Snes9x and WinAmp output can be heard at the same time.

  If your sound card isn't supported by DirectX very well (or not at all) you
  will have to use FMOD's WAVE output option; but WAVE output introduces a 
  0.15s delay between Snes9x generating sample data and you hearing it. 
  Select FMOD's WAVE output by choosing the "FMOD Windows Multimedia" sound
  driver option from the Sound Settings dialog.

- The sound card's volume level might be set too low. Snes9x doesn't alter the 
  card's master volume level so you might need to adjust it using the sound
  card's mixer/volume 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.
- You've turned off sound CPU emulation, clicked the Mute button in the
  sound settings dialog, or set the playback rate to "<No sound>".

General sound problems:
- A continuous, crackling sound or buzz can be heard.

  First make sure it is happening in all games - Snes9x still does have one or
  two sound emulation bugs that cause the odd pop, crackle and buzz in a few
  games.

  Once you're happy that it is not just the game you're playing, set the 
  playback rate in the Sound Settings dialog to 22KHz, and uncheck "Stereo" and
  "16bit playback". Next set both sound buffer length and mix values to 10ms,
  then try slowly increasing both values until clear sound can be heard. The 
  ideal is that the mix interval and sound buffer length values should be as
  small as possible. The mix interval value must always be smaller than the
  sound buffer length otherwise sound data will be lost.
  
  If your sound card requires larger values, above, say, 40ms, then it might
  also be necessary to enable the "Generate sample data in sync with sound CPU"
  option to maintain accurate sound emulation.
  
  If all else fails, try selecting the "FMOD Window Multimedia" sound driver 
  option and live with the 0.15s lagged sound that is unavoidable when using 
  the older Windows WAVE sound API.

  Once you have clear sound, set the playback rate, 16bit sound and stereo 
  settings to quality you would like - it might be necessary to tweak the 
  sound buffer length and mix interval values again.

- Sound the lagged/delayed compared to on-screen action. If you're using the
  "FMOD Windows Multimedia" sound driver then delayed sound is unavoidable;
  otherwise your sound buffer length/mix interval settings are too large - if
  you can, reduce their values.
- Sound quality is poor on all games. You might have a noisy sound card 
  (usually cheaper sound cards), turning on 16-bit, interpolated sound, 
  sync-sound and/or increasing the playback rate might help.
- Sound seems to have gaps. Using larger sound buffer or mix interval values
  can cause this; reduce them if you can, or click on the "Generate sample data
  in sync with sound CPU" option.
- 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 (uncheck the 16bit playback option), mono (uncheck the Stereo option)
  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 card.

If all else fails, try posting a message describing your problem and 
requesting help on the Snes9X message board at the Snes9X web site, 
http://www.snes9x.com

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.

Emulation speed
===============

Emulating an SNES is very processor intensive, with its two or sometimes 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
help.

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
emulation speed.

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 or sync-sound modes, or turning off sound CPU emulation altogether
will also help boost emulation speed.

Credits
-------

- Jerremy Koot for all his hard work on previous versions of Snes96, Snes97 
  and Snes9x.
- Ivar for the original Super FX C emulation, DSP-1 emulation work and 
  information on both chips.
- zsKnight and _Demo_ for the Intel Super FX assembler, DSP-1 and C4 emulation
  code.
- zsKnight and _Demo_ for all the other ideas and code I've nicked off them; 
  they've nicked lots of my ideas and information too!
- John Weidman and Darkforce for the S-RTC emulation information and code.
- Kreed for his excellent image enhancer routines.
- Nose000 for code changes to support various Japanese SNES games.
- Neill Corlett for the IPS patching support code.
- DiskDude's SNES Kart v1.6 document for the Game Genie(TM) and Pro-Action 
  Replay cheat system information.
- Lord ESNES for some nice chats and generally useful stuff.
- Lee Hyde (lee@jlp1.demon.co.uk) 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 the original sound interpolation code (never used directly
  due to problems).
- Takehiro TOMINAGA for many speed up suggestions and bug fixes.
- Predicador for the Windows icon.
- Lindsey Dubb for the mode 7 bi-linear filter code and the improved 
  colour addition and subtraction code.
- Anti Resonance for his super-human efforts to help get his fast sound CPU
  core and sound DSP core working in Snes9x.

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 registered trademark of X/Open.
Glide is a trademark of 3Dfx Interactive, inc.

------------------------------------------------------------------------------
Gary Henderson
gary@snes9x.com