                    MULTIPLE INVADERS EMULATOR VERSION 2.00
                                BY MARK HAZELWOOD


BACKGROUND:

This emulator was written as a test because I really wanted to play
another game "GORF" but no one has started to write an emulator for it.
So I thought I would try to write a "GORF" emulator but I needed to start
on something easy.

After reading the Arcade Emulator How To FAQ and reading Neil Bradley's
comments about how easy it was to write a Space Invaders emulator, I
thought this would be a good place to start.


GETTING STARTED:

You will obviously need the ROMs and I will not provide them.

It uses the standard names of the ROMs available at the TANT archive.

Space Invaders
==============
INVADERS/INVADERS.E
INVADERS/INVADERS.F
INVADERS/INVADERS.G
INVADERS/INVADERS.H

Space Invaders Deluxe
=====================
INVDELUX/INVDELUX.D
INVDELUX/INVDELUX.E
INVDELUX/INVDELUX.F
INVDELUX/INVDELUX.G
INVDELUX/INVDELUX.H

Space Attack II
===============
SATTACK/SATTACK.E
SATTACK/SATTACK.F
SATTACK/SATTACK.G
SATTACK/SATTACK.H

Super Earth Invasion
====================
EARTHINV/EARTHINV.E
EARTHINV/EARTHINV.F
EARTHINV/EARTHINV.G
EARTHINV/EARTHINV.G

Galaxy Wars
===========
GALXWARS/GALXWARS.0
GALXWARS/GALXWARS.1
GALXWARS/GALXWARS.2
GALXWARS/GALXWARS.3
GALXWARS/GALXWARS.4
GALXWARS/GALXWARS.5

Lunar Rescue
============
LRESCUE/LRESCUE.1
LRESCUE/LRESCUE.2
LRESCUE/LRESCUE.3
LRESCUE/LRESCUE.4
LRESCUE/LRESCUE.5
LRESCUE/LRESCUE.6


Destination Earth
=================
DESTERTH/31_C.BIN
DESTERTH/32_D.BIN
DESTERTH/33_E.BIN
DESTERTH/34_F.BIN
DESTERTH/35_G.BIN
DESTERTH/36_H.BIN
DESTERTH/42_B.BIN

Invader's Revenge
=================
INVRVNGE/INVRVNGE.E
INVRVNGE/INVRVNGE.F
INVRVNGE/INVRVNGE.G
INVRVNGE/INVRVNGE.H


Just put the ROM's in their corresponding sub-directory.

SOUND
=====
The emulator uses the BWSB v1.20 library for sound support. You will need to
run SETUP to select your sound card, test it and save the settings.

Type MIE to start the emulator in Mode Q.
You may use option /1, /2 or /3 for different video modes.
SEE OPTIONS FOR VIDEO MODES BELOW

A menu will appear where you can select a game to play.

The function keys can be used to adjust the port settings.

<F1> - <F8> for PORT 1

<SHIFT> <F1> - <F8> for PORT2

Bits 0 & 1 of Port 2 control the number of ships in Space Invaders.
00 = 3 ships
01 = 4 ships
10 = 5 ships
11 = 6 ships

Bit 2 is the TILT switch

Bit 3 of port 2 controls the extra ship in Space Invaders.
0 = extra ship at 1500
1 = extra ship at 1000

Try out the settings for other games.

Controls are:

'3' = Coin
'2' = 2 Players
'1' = 1 Player

'CTRL' and 'ALT' = Fire

Arrow keys = Move left and right

'ESC' = Quit

PROGRAMMING:

This emulator is written entirely in assembly language. As a result, this will
run just fine on a 386. This also accounts for the small size of the
emulator. By using Assembly language, I never had to worry about the
speed of the emulation being to slow.


The emulator now uses a Mode Q. It also has a tweaked Mode Q that will
work on some other desktops and laptop computers.

The default is Mode Q. If this doesn't work on your computer try starting
the emulator with the "/1" switch. This will use the tweaked Mode Q.

There is also a tweaked Mode 0E that works where Mode Q may not. Select this
mode using the "/2" switch.

There is also a Mode 12 that displays a small screen. Select this mode using 
the "/3" switch.

Let me know of any problems using these modes.

THANKS:

Thanks must go to Neil Bradley for sharing his wealth of information.

Thanks to Michael Adcock for putting together the Arcade Emualtion How To FAQ.

Thanks to Nemoto Yohei for the detailed Space Invaders memory map
and port info.

Thanks to Mark Incley for a great Z80 disassembler.

Thanks to Phil Morris for all the suggestions and testing.

Thanks to Edward Schlunder for the BWSB Music and Sound library.

This emulator is FREEWARE.


COMMENTS:

Any comments/questions send e-mail to MarkHazel@AOL.COM


VERSION UPDATES:

2.00        Added sound support using BWSB version 1.20.
            Added dip switch selection using the input ports.
            Added two new video modes.
            Added a menu screen for game selection.
            Added support for Destination Earth.
            Added support for Galaxy Wars.
            Added CPU detection for correct speed adjustment.

1.02        Fixed the shots. Thanks to Warren Mills.
            Re-adjusted colors.
            A quick note about color:
                  Space Invaders was essentially a black and white
                  display. To achieve color, a colored film was pasted
                  over the CRT display. A green film covered the bottom
                  of the screen and a red film covered the space between
                  the invaders and the score. The machine I am using as a
                  model has faded quite a bit. The colors in the emulation
                  are a best guess at what the colors should be.

1.01:       Now uses a tweaked Mode Q that works on laptops.
            Fixed color.
            Fixed speed problem.
