

                        ******* VGB *******
                           Virtual Gameboy 
                             version 1.4

                         by Marat Fayzullin
                      
	             Acorn Port by David McEwen 
	             Port Version : 1.4 (09/01/99) 


Please note a change of contact info. My new home email is : david@acornemus.freeserve.co.uk
Website is unaffected. Also do not ask me for ROMS, I will not provide any, and will if 
pestered inform the relevant authorities.

	             
New In This Version
-------------------

	* More speed
		- A definite increase 
		   - should help all those people with lowly SA less machines 
		- The method used may cause minor corruption in the last couple of columns
		- Also scrolling can be jerky... but it runs so much faster it doesn't matter   
	* Cheat codes (both Game Shark & Game Genie) - see below
	* Seems a lot more stable to me
	* All features from the main 1.4 source -> Zelda DX now works as does Wario 2 CGB
	  	- This is also one of the few emulators that can run Disney's Bug's Life
	* Super GB colours fixed
	* Super GB & Colour GB palette setting sped up...
        * On Colour GB I have sped up palette setting on a Risc PC by only setting the physical
          palette once for every four colour changes - larger values caused strange effects...
          I might make this configurable in the future

Coming Soon
-----------

	* Direct MIDI output
	* Compatibility with !Gameboy Save files
	* Colour alteration when in ordinary GB mode 
	* Sound
	* Bug fixes... I'm preempting problems

	                          
Introduction
------------

This is a port of Marat's Gameboy emulator. It emulates all gameboy stuff... Pocket GB, 
Super GB, Colour GB and even support for combined Colour & Super GB.

Use it to play the best version of Tetris anywhere!!!

OK a challenge... can anyone beat my Tetris score (1288 lines) ??
<NB this was achieved on a real Gameboy Color not the emulator>


Note for users of old machines
------------------------------

The best way of using it is to increase the Uperiod and decrease the Vperiod in the 
options window. Please note that for older machines eg A5000... the screen mode will
always be 320 by 256. This will be Mode 13 in 256 colours.
The reasons for this are speed and guaranteeing the user has the right mode.


How do I use it ?
-----------------

Easy - just download a game from the internet there are various good sites around 
and few companies actually care what happens with these roms since they are in 
many cases over 10 years old and noone is really going to buy them in this day 
and age. One of the best sites is Daves Arcade Classics, great for MAME roms as well.

Once you have some ROMS you can run them by setting the filetype to Gameboy and 
double clicking or dragging the game to the VGB icon. This loads the ROM.
Now there is no need to decompress files!! You can run straight from a Gzipped or
singularly PKZipped file - save a bit of Hard Drive space... 

It is fairly intuitive to use... 

The keys during emulation are :


  Cursor keys control movement

  [SPACE]  - SELECT button   
  [ALT]    - B button 
  [CTRL]   - A button
  [RETURN] - START button
  [ESC]  - Exit
  
The frontend allows you to alter various variables that will affect the
speed of the game - the Uperiod and Vperiod values. Uperiod is sort of equivalent 
to a frame skip, and Vperiod is the clock cycles per screen refresh. The lower the
value the more probs that may occur... some games require higher values to work well.

There are several resolution choices available. The first 4 are simple resolutions
no scaling is implemented. There is a full screen mode. If using Super GB the mode will be 256 by 256, otherwise it'll be 320 by 288, which plots 4 times as many pixels!! An MDF is included for these modes. If for whatever reason the modes cannot be found Mode 13 (320 by 256) is used.

The Delay option determines whether VRAM reads are delayed or not. This may make games
work better or worse...

The pause function mean that when you press Escape the emulation isn't killed
instead it is paused so that it can be continued from that point by clicking on the
icon. If you wish to reset the emulation either press F5 while in the emulator or
click on Reset in the menu.

For those with StrongARMs there is a frame locking option, which forces update to 
the set number of FPS regardless of the refresh rate of the mode it is running in!!

Auto frame rate is active on slow machines with frame locking on. This will try and 
match frame skipping to your system, but is far from perfect. I'm doing lots of 
optimizations to the emulators and hopefully this will help.

Save RAM support is available. Just drag the save file to a location on the harddrive 
and rename as appropriate. Or drag an existing *VGB* save ram file to the options window.
Every time you return to the desktop the SRAM is updated.
 
No sound option in this release... my development version sounds horrible! you can log 
sound to a MIDI file though.  

A future release should hopefully be running in a window... I will try and optimise as
much of the code as I can!! This may also mean that it becomes more playable on older
machines, but please do not expect miracles.

CHEATS
------

To add cheats simply open the cheats menu using the option on the main menu.
Then click on a tick to unfade a writable field. Then type in your cheat code and click on
OK. When you drag a new rom to the icon the cheats will be active. 

The cheats will be stored throughout the session, so if you drag another rom to the icon be 
sure to untick all the boxes.

In future you will be able to save out cheats...

 
*FAQ*
----- 

Why are my Roms images not working ?
-------------------

Some Colour Roms don't work properly yet, but you can get them to work in colour
by using the Super GB option.
Try downloading them again. If there is still no joy. Send the image to 
Marat and see if he can find a reason. 

Where's the sound ?
-------------------

When it sounds nice I'll add it. I'll probably do a direct MIDI output too.


Do I need a special screen mode ?
---------------------------------

Nope the emulator runs happily in a 320 by 256 mode as the screen fits nicely. 
The full screen modes require  specially defined modes... a Mode Definition File 
is included. It runs in either 16 or 256 colours - it just depends on your taste!

Will you get it to run in the desktop ?
---------------------------------------

Moon on a stick anyone !!


Will you be porting any other emulators ?
-----------------------------------------

Errrr...

You would think I'd have had enough by now!!

Current list :

	This one -> VGB
	MGear
	ColEm
	fMsx
	Stella
	Atari 800
	TI8x 
	ArcNes
	AdamEm
	MadNES


Copyright and Disclaimer
------------------------

This emulator is copyright Marat Fayzullin 1994-8, and the Acorn-specific
components are copyright David McEwen 1998. You may not attempt to pass off
any part of this work as your own, although you may distribute it freely as
long as you supply the complete archive (that is, all the files supplied to
you).

This software is supplied "as is". I make no claims about the reliability or
suitability for any purpose of this emulator, and any use of it is undertaken
at your own risk. No responsibility is taken for any failure of the software,
or for any loss or damage caused directly or indirectly by the software.

Whilst I will endeavour to help you if you have problems with this emulator,
no such support is guaranteed.

In the above "This emulator" refers to everything supplied within this
archive, which is specifically the !VGB application and all the files
contained within it, and also the documentation files (including the one you
are reading now).



COMMENTS
--------

Any comments about the emulator as such should go to Marat Fayzullin : 
email : fms@komkon.org
Website : http://www.komkon.org/fms

Any comments about the Acorn specific parts and please no inane emails giving 
me ways of making money etc... just useful constructive stuff please
email : david@acornemus.freeserve.co.uk (Home)
	davidm@argonaut.com (Work)
Website : http://www.lizjay.demon.co.uk/david

Thanks
------

Marat for letting me have the source...
Gareth Moore for testing and getting info on his site so quick!
Dave Sharp for testing on his aged A5000
Michael Koenig for testing this and many other emulators...
Nintendo for making such a cute machine - buy one, go on you know you want to!!

