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Amiga Format CD 23
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Amiga Format AFCD23 (Feb 1998, Issue 107).iso
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emulation
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computers
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mission
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mission.txt
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1997-12-12
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******* Mission *******
The ColecoVision Emulator for the MSX
Version 1.1
Copyright (C) 1996 Marcel de Kogel
Hardware and Software Requirements
==================================
An MSX1 with 64K RAM minimum (an MSX2 is recommended)
MSX-DOS
Some ColecoVision ROM images
Both PSG and SCC and up to two joysticks are supported. The emulator will
automatically detect and use an SCC cartridge in either slot 1 or 2
Files included
==============
mission.com The emulator
mission.txt This file
coleco.rom ColecoVision OS ROM image. Since the emulator makes some
assumptions of where certain OS routines are located, you may
not be able to use different OS ROM images
The latest version of Mission can always be found on the Mission
distribution site at http://www.komkon.org/~dekogel/mission.html
Note
====
Since the program emulates a ColecoVision by patching the OS ROM, many
games will not run on the emulator. About 1/3rd of all images I've tested
run correctly, a few more run, but with flaws (e.g. corrupted graphics or
sound). Also, because the MSX is significantly slower than the
ColecoVision, you may find fewer games run correctly if you're using a
60Hz (NTSC) display. If you're having trouble running some games, try
switching to 50Hz mode
Key Mappings
============
F1 - Pause emulation
F2 - Continue emulation
F4 - Quit emulator (only works on MSX2 systems) to 40 column
text mode. Please note that this will not work properly if
you started the emulator in 80 column mode
SELECT - Quit emulator (only works on MSX2 systems) to 80 column
text mode. Please note that this will not work properly if
you started the emulator in 40 column mode
F5 - ColecoVision reset switch
STOP - Toggle slow mode. For all cheaters out there
INS - Map keyboard to joystick port #1 (default)
DEL - Map keyboard to joystick port #2
Cursor keys - Joystick movement
Space, M - Joystick first button
N - Joystick second button
B - Joystick third button
V - Joystick fourth button
0-9 - Keypad key buttons
- - Keypad * button
= - Keypad # button
Starting the emulator
=====================
To start the emulator, simply type MISSION <filename> <ENTER>. If no
filename is given, the emulator will load and execute CART.ROM, if
present. The extension of your game ROM images is assumed to be .ROM. If a
file CART.PAT is present, the emulator will load it and use it to patch
CART.ROM
Patch file format
=================
The patch file (*.PAT) format is as follows:
String "Mission Patch File",$1A
Word Size of ROM image in bytes
Word ROM image checksum. This is the sum of all bytes in the image
Word Number of patches to apply
Patch data follows and has this format:
Word Offset in image of this patch
Byte New value
Creating patch files
====================
Below are some addresses useful for those who want to create patch files:
Offset Type Contents/Function
------ ---- -----------------
$3f00 String "MISSION"
$3f07 Byte Emulator version number. The high nibble contains the
major version number, the low nibble the minor version
number. Currently, this byte contains $11
$3f10 Byte Current joypad #1 status
$3f11 Byte Current keypad #1 status
$3f12 Byte Current joypad #2 status
$3f13 Byte Current keypad #2 status
$3f14 Byte Current VDP status byte. Calling the READ_VDP_STATUS
routine ($1fdc) modifies this; using this routine is
highly recommended
$3f80 Subroutine Send A to the sound chip, you can also use location
$335. Please note that calling this function does not
change the PSG/SCC settings
$3f83 Subroutine Interpret sound chip data, this is called at every
interrupt
$3f86 Subroutine Update current controller statuses. This is also called
by the interrupt routine
The subroutines do not change any register unless specified otherwise, and
use no stack space
If the upper two bits of the first byte of a cartridge image are both
cleared, the lower bits have the following function:
Bit Function
--- --------
0 This game does not use the VDP_OUT routine ($1fd9) to set VDP register
#1. Setting this bit ensures interrupts are passed to the cartridge
NMI handler
1-5 Reserved
If the first instruction of a game (the one pointed to by [$800a])is LD
SP,nnnn; the emulator will replace it with LD SP,$7ff0. If a game runs out
of stack space, try changing the first instruction, or add a LD SP,nnnn
instruction somewhere in it's initialisation routine. ColecoVision RAM is
at $7000-$73ff, all other memory between $4000-$7fff can be used freely
Legal issues
============
This software can be used free of charge and may be distributed freely, as
long as the archive isn't modified in any way, no profit is made from
distributing it, and no game ROMs are supplied with it. Also, this
software comes without any warranty, neither express nor implied: Use at
your own risk
History
=======
1.1 31-12-1996 Some (minor) bug fixes, added slow mode, keyboard can
now be mapped to joystick port #2, improved SCC support
and added 80 column support, removed separate NTSC
version, pause feature stabilised, added support for
patch files
1.0 30-11-1996 Initial release
Please send your comments to Marcel at
m.dekogel@student.utwente.nl