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Catalogue of Arcade Emulation Software - the Absolute Reference

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X-Arcade

X-Arcade

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megatech.c

0.100u2 [David Haywood]


TODO:

- Cleanup, fix so that everything works properly

- Rewrite genesis emulation (so that it works perfectly with every genesis game). Games are marked as NOT WORKING due to a) bad genesis emulation, b) incorrect behavior at time out or c) they're sms based games which aren't yet supported.


NOTES:

- Megatech games are identical to their Genesis/SMS equivlents, however the Megatech cartridges contain a BIOS rom with the game instructions. The last part number of the bios ROM is the cart/game ID code. In Megatech games your coins buy you time to play the game, how you perform in the game does not matter, you can die and start a new game providing you still have time, likewise you can be playing well and run out of time if you fail to insert more coins. This is the same method Nintendo used with their Playchoice 10 system. The BIOS screen is based around SMS hardware, with an additional Z80 and SMS VDP chip not present on a standard Genesis. SMS games run on Megatech in the Genesis's SMS compatability mode, where the Genesis Z80 becomes the main CPU and the Genesis VDP acts in a mode mimicing the behavior of the SMS VDP. Additions will only be made to this driver if proof that the dumped set are original roms with original Sega part numbers is given... A fairly significant number of Genesis games were available for this system.


WIP:

- 15th August 2006: David Haywood - Continued to work on the Master System, made some improvements. Fantastic Dizzy is now playable, but imperfect (the status bar flickers on the Inventory screen) Cosmic Spacehead (another Codemasters game) runs pretty well too.

- 14th August 2006: David Haywood - I've decided to start adding some Master System support to the MegaDrive Emu. This will be needed by MAME for improved emulation of the Megatech Menu, and the SMS games running on Megatech hardware. It's still in a prelminary state, but I have this title screen from Fantastic Dizzy, one of my favourite games on the SMS. IMO this is the best version of the game because despite having weaker graphics than the 16-bit versions it has a far superior interface / control system, anyway, for now it doesn't get any further than the title screen and the scrolls are missing. As a side note this game is incredibly sensitive to frameskipping, so much so that it doesn't really work properly in Kega. If Kega skips a frame because something else takes focus, or steals some CPU cycles (or if you put it into full-throttle mode) the whole game crashes. According to Charles Macdonald this is because the game checks the collision flag rather often, and if the results aren't right it will crash. This means to emulate it properly in MAME the video must be fully emulated every frame, regardless of frameskipping (as was the case with the Megadrive).

- 0.106u9: David Haywood updated the MegaTech driver to support dualscreen (256x192 and 320x224).

- 19th November 2005: Charles MacDonald - I designing an adapter to read bankswitched SMS / MegaTech ROMs.

- 0.100u3: More Genesis-based games cleanup [Aaron Giles]. Fixed crashes introduced in last version and centralized interrupt generation for all Genesis-based games. Changed palettesize to 96 colors.

- 0.100u2: David Haywood separated the Sega C2 driver into several other pieces. Aaron Giles fixed column scroll with a line scroll of 8, cleaned up input ports and filled out memory map according to cgfm's documentation.